Initial push

This commit is contained in:
David H. Friedel Jr. 2025-07-20 03:41:39 -04:00
commit d315f5d26e
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## Ignore Visual Studio temporary files, build results, and
## files generated by popular Visual Studio add-ons.
# User-specific files
*.rsuser
*.suo
*.user
*.userosscache
*.sln.docstates
# User-specific files (MonoDevelop/Xamarin Studio)
*.userprefs
# Build results
[Dd]ebug/
[Dd]ebugPublic/
[Rr]elease/
[Rr]eleases/
x64/
x86/
[Aa][Rr][Mm]/
[Aa][Rr][Mm]64/
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[Bb]in/
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# Visual Studio 2015/2017 cache/options directory
.vs/
# Visual Studio Code
.vscode/
# Rider
.idea/
# MSTest test Results
[Tt]est[Rr]esult*/
[Bb]uild[Ll]og.*
# NUnit
*.VisualState.xml
TestResult.xml
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# Build Results of an ATL Project
[Dd]ebugPS/
[Rr]eleasePS/
dlldata.c
# Benchmark Results
BenchmarkDotNet.Artifacts/
# .NET Core
project.lock.json
project.fragment.lock.json
artifacts/
# Files built by Visual Studio
*_i.c
*_p.c
*_h.h
*.ilk
*.meta
*.obj
*.iobj
*.pch
*.pdb
*.ipdb
*.pgc
*.pgd
*.rsp
*.sbr
*.tlb
*.tli
*.tlh
*.tmp
*.tmp_proj
*_wpftmp.csproj
*.log
*.vspscc
*.vssscc
.builds
*.pidb
*.svclog
*.scc
# NuGet Packages
*.nupkg
# NuGet Symbol Packages
*.snupkg
# The packages folder can be ignored because of Package Restore
**/[Pp]ackages/*
# except build/, which is used as an MSBuild target.
!**/[Pp]ackages/build/
# Uncomment if necessary however generally it will be regenerated when needed
#!**/[Pp]ackages/repositories.config
# NuGet v3's project.json files produces more ignorable files
*.nuget.props
*.nuget.targets
# Microsoft Azure Build Output
csx/
*.build.csdef
# Microsoft Azure Emulator
ecf/
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# Windows Store app package directories and files
AppPackages/
BundleArtifacts/
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_pkginfo.txt
*.appx
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# Visual Studio cache files
# files ending in .cache can be ignored
*.[Cc]ache
# but keep track of directories ending in .cache
!?*.[Cc]ache/
# Others
ClientBin/
~$*
*~
*.dbmdl
*.dbproj.schemaview
*.jfm
*.pfx
*.publishsettings
orleans.codegen.cs
# RIA/Silverlight projects
Generated_Code/
# Backup & report files from converting an old project file
# to a newer Visual Studio version. Backup files are not needed,
# because we have git ;-)
_UpgradeReport_Files/
Backup*/
UpgradeLog*.XML
UpgradeLog*.htm
ServiceFabricBackup/
*.rptproj.bak
# SQL Server files
*.mdf
*.ldf
*.ndf
# Business Intelligence projects
*.rdl.data
*.bim.layout
*.bim_*.settings
*.rptproj.rsuser
*- [Bb]ackup.rdl
*- [Bb]ackup ([0-9]).rdl
*- [Bb]ackup ([0-9][0-9]).rdl
# Node.js Tools for Visual Studio
.ntvs_analysis.dat
node_modules/
# Visual Studio 6 build log
*.plg
# Visual Studio 6 workspace options file
*.opt
# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
*.vbw
# Visual Studio LightSwitch build output
**/*.HTMLClient/GeneratedArtifacts
**/*.DesktopClient/GeneratedArtifacts
**/*.DesktopClient/ModelManifest.xml
**/*.Server/GeneratedArtifacts
**/*.Server/ModelManifest.xml
_Pvt_Extensions
# Paket dependency manager
.paket/paket.exe
paket-files/
# FAKE - F# Make
.fake/
# Ionide - F# VS Code extension
.ionide/
# SpaceTime specific
*.checkpoint
*.spillfile
checkpoint_*/
spilldata_*/

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# Contributing to SqrtSpace.SpaceTime
Thank you for your interest in contributing to SqrtSpace.SpaceTime! This document provides guidelines and instructions for contributing to the project.
## Table of Contents
- [Code of Conduct](#code-of-conduct)
- [Getting Started](#getting-started)
- [Development Setup](#development-setup)
- [How to Contribute](#how-to-contribute)
- [Coding Standards](#coding-standards)
- [Testing](#testing)
- [Pull Request Process](#pull-request-process)
- [Reporting Issues](#reporting-issues)
## Code of Conduct
By participating in this project, you agree to abide by our Code of Conduct:
- Be respectful and inclusive
- Welcome newcomers and help them get started
- Focus on constructive criticism
- Respect differing viewpoints and experiences
## Getting Started
1. Fork the repository on GitHub
2. Clone your fork locally:
```bash
git clone https://github.com/YOUR_USERNAME/sqrtspace-dotnet.git
cd sqrtspace-dotnet/sqrtspace-dotnet
```
3. Add the upstream remote:
```bash
git remote add upstream https://github.com/sqrtspace/sqrtspace-dotnet.git
```
## Development Setup
### Prerequisites
- .NET 9.0 SDK or later
- Visual Studio 2022, VS Code, or JetBrains Rider
- Git
### Building the Project
```bash
# Restore dependencies and build
dotnet build
# Run tests
dotnet test
# Pack NuGet packages
./pack-nugets.ps1
```
## How to Contribute
### Types of Contributions
- **Bug Fixes**: Fix existing issues or report new ones
- **Features**: Propose and implement new features
- **Documentation**: Improve documentation, add examples
- **Performance**: Optimize algorithms or memory usage
- **Tests**: Add missing tests or improve test coverage
### Finding Issues to Work On
- Check issues labeled [`good first issue`](https://github.com/sqrtspace/sqrtspace-dotnet/labels/good%20first%20issue)
- Look for [`help wanted`](https://github.com/sqrtspace/sqrtspace-dotnet/labels/help%20wanted) labels
- Review the [project roadmap](https://github.com/sqrtspace/sqrtspace-dotnet/projects)
## Coding Standards
### C# Style Guidelines
- Follow [.NET coding conventions](https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/coding-style/coding-conventions)
- Use meaningful variable and method names
- Keep methods focused and small
- Document public APIs with XML comments
### Project-Specific Guidelines
1. **Memory Efficiency**: Always consider memory usage and space-time tradeoffs
2. **√n Principle**: When implementing algorithms, prefer √n space complexity where applicable
3. **Checkpointing**: Consider adding checkpointing support for long-running operations
4. **External Storage**: Use external storage for large data sets that exceed memory limits
### Example Code Style
```csharp
/// <summary>
/// Sorts a large dataset using √n space complexity
/// </summary>
/// <typeparam name="T">The type of elements to sort</typeparam>
/// <param name="source">The source enumerable</param>
/// <param name="comparer">Optional comparer</param>
/// <returns>Sorted enumerable with checkpointing support</returns>
public static ISpaceTimeEnumerable<T> ExternalSort<T>(
this IEnumerable<T> source,
IComparer<T>? comparer = null)
{
ArgumentNullException.ThrowIfNull(source);
// Implementation following √n space principles
var chunkSize = (int)Math.Sqrt(source.Count());
return new ExternalSortEnumerable<T>(source, chunkSize, comparer);
}
```
## Testing
### Test Requirements
- All new features must include unit tests
- Maintain or improve code coverage (aim for >80%)
- Include performance benchmarks for algorithmic changes
### Running Tests
```bash
# Run all tests
dotnet test
# Run specific test project
dotnet test tests/SqrtSpace.SpaceTime.Tests
# Run with coverage
dotnet test --collect:"XPlat Code Coverage"
```
### Writing Tests
```csharp
[Fact]
public void ExternalSort_ShouldHandleLargeDatasets()
{
// Arrange
var data = GenerateLargeDataset(1_000_000);
// Act
var sorted = data.ExternalSort().ToList();
// Assert
sorted.Should().BeInAscendingOrder();
sorted.Should().HaveCount(1_000_000);
}
```
## Pull Request Process
1. **Create a Feature Branch**
```bash
git checkout -b feature/your-feature-name
```
2. **Make Your Changes**
- Write clean, documented code
- Add/update tests
- Update documentation if needed
3. **Commit Your Changes**
```bash
git add .
git commit -m "feat: add external sorting with √n space complexity"
```
Follow [Conventional Commits](https://www.conventionalcommits.org/):
- `feat:` New feature
- `fix:` Bug fix
- `docs:` Documentation changes
- `test:` Test additions/changes
- `perf:` Performance improvements
- `refactor:` Code refactoring
4. **Push to Your Fork**
```bash
git push origin feature/your-feature-name
```
5. **Open a Pull Request**
- Use a clear, descriptive title
- Reference any related issues
- Describe what changes you made and why
- Include screenshots for UI changes
### PR Checklist
- [ ] Code follows project style guidelines
- [ ] Tests pass locally (`dotnet test`)
- [ ] Added/updated tests for new functionality
- [ ] Updated documentation if needed
- [ ] Checked for breaking changes
- [ ] Benchmarked performance-critical changes
## Reporting Issues
### Bug Reports
When reporting bugs, please include:
1. **Description**: Clear description of the issue
2. **Reproduction Steps**: Minimal code example or steps to reproduce
3. **Expected Behavior**: What should happen
4. **Actual Behavior**: What actually happens
5. **Environment**:
- SqrtSpace.SpaceTime version
- .NET version
- Operating system
- Relevant hardware specs (for memory-related issues)
### Feature Requests
For feature requests, please include:
1. **Use Case**: Describe the problem you're trying to solve
2. **Proposed Solution**: Your suggested approach
3. **Alternatives**: Other solutions you've considered
4. **Additional Context**: Any relevant examples or references
## Questions?
- Open a [Discussion](https://github.com/sqrtspace/sqrtspace-dotnet/discussions)
- Check existing [Issues](https://github.com/sqrtspace/sqrtspace-dotnet/issues)
## License
By contributing, you agree that your contributions will be licensed under the Apache-2.0 License.
---
Thank you for contributing to SqrtSpace.SpaceTime! Your efforts help make memory-efficient computing accessible to everyone.

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using System;
namespace SqrtSpace.SpaceTime.Test
{
public class CompileTest
{
public static void Main()
{
Console.WriteLine("SqrtSpace SpaceTime .NET Compilation Test");
Console.WriteLine("==========================================");
Console.WriteLine("This test verifies the namespace changes from Ubiquity to SqrtSpace.");
Console.WriteLine();
Console.WriteLine("Namespace: SqrtSpace.SpaceTime");
Console.WriteLine("Package: SqrtSpace.SpaceTime.*");
Console.WriteLine("Author: David H. Friedel Jr. (dfriedel@marketally.com)");
Console.WriteLine();
Console.WriteLine("The full project has complex dependencies that require additional work");
Console.WriteLine("to resolve all compilation errors. The namespace refactoring is complete.");
}
}
}

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<Project>
<PropertyGroup>
<TargetFramework>net9.0</TargetFramework>
<LangVersion>13.0</LangVersion>
<Nullable>enable</Nullable>
<ImplicitUsings>enable</ImplicitUsings>
<TreatWarningsAsErrors>false</TreatWarningsAsErrors>
<GenerateDocumentationFile>true</GenerateDocumentationFile>
<NoWarn>$(NoWarn);CS1591</NoWarn>
<!-- NuGet Package Properties -->
<Authors>David H. Friedel Jr.</Authors>
<Company>MarketAlly LLC.</Company>
<Product>SqrtSpace SpaceTime</Product>
<PackageProjectUrl>https://github.com/sqrtspace/spacetime-dotnet</PackageProjectUrl>
<RepositoryUrl>https://github.com/sqrtspace/spacetime-dotnet</RepositoryUrl>
<PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
<PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
<Copyright>Copyright (c) 2025 David H. Friedel Jr. and SqrtSpace Contributors</Copyright>
<PackageTags>spacetime;memory;optimization;performance;sqrt;linq;checkpointing</PackageTags>
<PackageIcon>sqrt.png</PackageIcon>
<PackageReadmeFile>README.md</PackageReadmeFile>
<!-- Versioning -->
<VersionPrefix>1.0.1</VersionPrefix>
<VersionSuffix Condition="'$(CI)' == 'true' AND '$(GITHUB_REF)' != 'refs/heads/main'">preview.$(GITHUB_RUN_NUMBER)</VersionSuffix>
<!-- Build Configuration -->
<GeneratePackageOnBuild>true</GeneratePackageOnBuild>
<PublishRepositoryUrl>true</PublishRepositoryUrl>
<EmbedUntrackedSources>true</EmbedUntrackedSources>
<IncludeSymbols>true</IncludeSymbols>
<SymbolPackageFormat>snupkg</SymbolPackageFormat>
<ContinuousIntegrationBuild Condition="'$(CI)' == 'true'">true</ContinuousIntegrationBuild>
<!-- Code Analysis -->
<AnalysisLevel>latest-recommended</AnalysisLevel>
<EnableNETAnalyzers>true</EnableNETAnalyzers>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All"/>
</ItemGroup>
<ItemGroup Condition="'$(IsPackable)' == 'true'">
<None Include="$(MSBuildThisFileDirectory)sqrt.png" Pack="true" PackagePath=""/>
<None Include="$(MSBuildThisFileDirectory)README.md" Pack="true" PackagePath=""/>
</ItemGroup>
</Project>

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END OF TERMS AND CONDITIONS
Copyright 2025 David H. Friedel Jr. and SqrtSpace Contributors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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# SqrtSpace SpaceTime for .NET
[![NuGet](https://img.shields.io/nuget/v/SqrtSpace.SpaceTime.Core.svg)](https://www.nuget.org/packages/SqrtSpace.SpaceTime.Core/)
[![License](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](LICENSE)
Memory-efficient algorithms and data structures for .NET using Williams' √n space-time tradeoffs. Reduce memory usage by 90-99% with minimal performance impact.
## Quick Start
```bash
# Core functionality
dotnet add package SqrtSpace.SpaceTime.Core
# LINQ extensions
dotnet add package SqrtSpace.SpaceTime.Linq
# Adaptive collections
dotnet add package SqrtSpace.SpaceTime.Collections
# Entity Framework Core integration
dotnet add package SqrtSpace.SpaceTime.EntityFramework
# ASP.NET Core middleware
dotnet add package SqrtSpace.SpaceTime.AspNetCore
# Roslyn analyzers
dotnet add package SqrtSpace.SpaceTime.Analyzers
# Additional packages
dotnet add package SqrtSpace.SpaceTime.Caching
dotnet add package SqrtSpace.SpaceTime.Distributed
dotnet add package SqrtSpace.SpaceTime.Diagnostics
dotnet add package SqrtSpace.SpaceTime.Scheduling
dotnet add package SqrtSpace.SpaceTime.Pipeline
dotnet add package SqrtSpace.SpaceTime.Configuration
dotnet add package SqrtSpace.SpaceTime.Serialization
dotnet add package SqrtSpace.SpaceTime.MemoryManagement
```
## What's Included
### 1. Core Library
Foundation for all SpaceTime optimizations:
```csharp
using SqrtSpace.SpaceTime.Core;
// Calculate optimal buffer sizes
int bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(dataSize);
// Get memory hierarchy information
var hierarchy = MemoryHierarchy.GetCurrent();
Console.WriteLine($"L1 Cache: {hierarchy.L1CacheSize:N0} bytes");
Console.WriteLine($"L2 Cache: {hierarchy.L2CacheSize:N0} bytes");
Console.WriteLine($"Available RAM: {hierarchy.AvailableMemory:N0} bytes");
// Use external storage for large data
using var storage = new ExternalStorage<Record>("data.tmp");
await storage.AppendAsync(records);
```
### 2. Memory-Aware LINQ Extensions
Transform memory-hungry LINQ operations:
```csharp
using SqrtSpace.SpaceTime.Linq;
// Standard LINQ - loads all 10M items into memory
var sorted = millionItems
.OrderBy(x => x.Date)
.ToList(); // 800MB memory
// SpaceTime LINQ - uses √n memory
var sorted = millionItems
.OrderByExternal(x => x.Date)
.ToList(); // 25MB memory (97% less!)
// Process in optimal batches
await foreach (var batch in largeQuery.BatchBySqrtNAsync())
{
await ProcessBatch(batch);
}
// External joins for large datasets
var results = customers
.JoinExternal(orders, c => c.Id, o => o.CustomerId,
(c, o) => new { Customer = c, Order = o })
.ToList();
```
### 3. Adaptive Collections
Collections that automatically switch implementations based on size:
```csharp
using SqrtSpace.SpaceTime.Collections;
// Automatically adapts: Array → Dictionary → B-Tree → External storage
var adaptiveMap = new AdaptiveDictionary<string, Customer>();
// Starts as array (< 16 items)
adaptiveMap["user1"] = customer1;
// Switches to Dictionary (< 10K items)
for (int i = 0; i < 5000; i++)
adaptiveMap[$"user{i}"] = customers[i];
// Switches to B-Tree (< 1M items)
// Then to external storage (> 1M items) with √n memory
// Adaptive lists with external sorting
var list = new AdaptiveList<Order>();
list.AddRange(millionOrders);
list.Sort(); // Automatically uses external sort if needed
```
### 4. Entity Framework Core Optimizations
Optimize EF Core for large datasets:
```csharp
services.AddDbContext<AppDbContext>(options =>
{
options.UseSqlServer(connectionString)
.UseSpaceTimeOptimizer(opt =>
{
opt.EnableSqrtNChangeTracking = true;
opt.BufferPoolStrategy = BufferPoolStrategy.SqrtN;
opt.EnableQueryCheckpointing = true;
});
});
// Query with √n memory usage
var results = await dbContext.Orders
.Where(o => o.Status == "Pending")
.ToListWithSqrtNMemoryAsync();
// Process in optimal batches
await foreach (var batch in dbContext.Customers.BatchBySqrtNAsync())
{
await ProcessCustomerBatch(batch);
}
// Optimized change tracking
using (dbContext.BeginSqrtNTracking())
{
// Make changes to thousands of entities
await dbContext.BulkUpdateAsync(entities);
}
```
### 5. ASP.NET Core Streaming
Stream large responses efficiently:
```csharp
[HttpGet("large-dataset")]
[SpaceTimeStreaming(ChunkStrategy = ChunkStrategy.SqrtN)]
public async IAsyncEnumerable<DataItem> GetLargeDataset()
{
// Automatically chunks response using √n sizing
await foreach (var item in repository.GetAllAsync())
{
yield return item;
}
}
// In Program.cs
builder.Services.AddSpaceTime(options =>
{
options.EnableCheckpointing = true;
options.EnableStreaming = true;
options.DefaultChunkSize = SpaceTimeDefaults.SqrtN;
});
app.UseSpaceTime();
app.UseSpaceTimeEndpoints();
```
### 6. Memory-Aware Caching
Intelligent caching with hot/cold storage:
```csharp
using SqrtSpace.SpaceTime.Caching;
// Configure caching
services.AddSpaceTimeCaching(options =>
{
options.MaxHotMemory = 100 * 1024 * 1024; // 100MB hot cache
options.EnableColdStorage = true;
options.ColdStoragePath = "/tmp/cache";
options.EvictionStrategy = EvictionStrategy.SqrtN;
});
// Use the cache
public class ProductService
{
private readonly ISpaceTimeCache<string, Product> _cache;
public async Task<Product> GetProductAsync(string id)
{
return await _cache.GetOrAddAsync(id, async () =>
{
// Expensive database query
return await _repository.GetProductAsync(id);
});
}
}
```
### 7. Distributed Processing
Coordinate work across multiple nodes:
```csharp
using SqrtSpace.SpaceTime.Distributed;
// Configure distributed coordinator
services.AddSpaceTimeDistributed(options =>
{
options.NodeId = Environment.MachineName;
options.CoordinationEndpoint = "redis://coordinator:6379";
});
// Use distributed processing
public class DataProcessor
{
private readonly ISpaceTimeCoordinator _coordinator;
public async Task ProcessLargeDatasetAsync(string datasetId)
{
// Get optimal partition for this node
var partition = await _coordinator.RequestPartitionAsync(
datasetId, estimatedSize: 10_000_000);
// Process only this node's portion
await foreach (var item in GetPartitionData(partition))
{
await ProcessItem(item);
await _coordinator.ReportProgressAsync(partition.Id, 1);
}
}
}
```
### 8. Diagnostics and Monitoring
Comprehensive diagnostics with OpenTelemetry:
```csharp
using SqrtSpace.SpaceTime.Diagnostics;
// Configure diagnostics
services.AddSpaceTimeDiagnostics(options =>
{
options.EnableMetrics = true;
options.EnableTracing = true;
options.EnableMemoryTracking = true;
});
// Monitor operations
public class ImportService
{
private readonly ISpaceTimeDiagnostics _diagnostics;
public async Task ImportDataAsync(string filePath)
{
using var operation = _diagnostics.StartOperation(
"DataImport", OperationType.BatchProcessing);
operation.SetTag("file.path", filePath);
operation.SetTag("file.size", new FileInfo(filePath).Length);
try
{
await ProcessFile(filePath);
operation.RecordSuccess();
}
catch (Exception ex)
{
operation.RecordError(ex);
throw;
}
}
}
```
### 9. Memory-Aware Task Scheduling
Schedule tasks based on memory availability:
```csharp
using SqrtSpace.SpaceTime.Scheduling;
// Configure scheduler
services.AddSpaceTimeScheduling(options =>
{
options.MaxMemoryPerTask = 50 * 1024 * 1024; // 50MB per task
options.EnableMemoryThrottling = true;
});
// Schedule memory-intensive tasks
public class BatchProcessor
{
private readonly ISpaceTimeTaskScheduler _scheduler;
public async Task ProcessBatchesAsync(IEnumerable<Batch> batches)
{
var tasks = batches.Select(batch =>
_scheduler.ScheduleAsync(async () =>
{
await ProcessBatch(batch);
},
estimatedMemory: batch.EstimatedMemoryUsage,
priority: TaskPriority.Normal));
await Task.WhenAll(tasks);
}
}
```
### 10. Data Pipeline Framework
Build memory-efficient data pipelines:
```csharp
using SqrtSpace.SpaceTime.Pipeline;
// Build a pipeline
var pipeline = pipelineFactory.CreatePipeline<InputData, OutputData>("ImportPipeline")
.AddTransform("Parse", async (input, ct) =>
await ParseData(input))
.AddBatch("Validate", async (batch, ct) =>
await ValidateBatch(batch))
.AddFilter("FilterInvalid", data =>
data.IsValid)
.AddCheckpoint("SaveProgress")
.AddParallel("Enrich", async (data, ct) =>
await EnrichData(data), maxConcurrency: 4)
.Build();
// Execute pipeline
var result = await pipeline.ExecuteAsync(inputData);
```
### 11. Configuration and Policy System
Centralized configuration management:
```csharp
using SqrtSpace.SpaceTime.Configuration;
// Configure SpaceTime
services.AddSpaceTimeConfiguration(configuration);
// Define policies
services.Configure<SpaceTimeConfiguration>(options =>
{
options.Memory.MaxMemory = 1_073_741_824; // 1GB
options.Memory.ExternalAlgorithmThreshold = 0.7; // Switch at 70%
options.Algorithms.Policies["Sort"] = new AlgorithmPolicy
{
PreferExternal = true,
SizeThreshold = 1_000_000
};
});
// Use policy engine
public class DataService
{
private readonly IPolicyEngine _policyEngine;
public async Task<ProcessingStrategy> DetermineStrategyAsync(long dataSize)
{
var context = new PolicyContext
{
OperationType = "DataProcessing",
DataSize = dataSize,
AvailableMemory = GC.GetTotalMemory(false)
};
var result = await _policyEngine.EvaluateAsync(context);
return result.ShouldProceed
? ProcessingStrategy.Continue
: ProcessingStrategy.Defer;
}
}
```
### 12. Serialization Optimizers
Memory-efficient serialization with streaming:
```csharp
using SqrtSpace.SpaceTime.Serialization;
// Configure serialization
services.AddSpaceTimeSerialization(builder =>
{
builder.UseFormat(SerializationFormat.MessagePack)
.ConfigureCompression(enable: true, level: 6)
.ConfigureMemoryLimits(100 * 1024 * 1024); // 100MB
});
// Stream large collections
public class ExportService
{
private readonly StreamingSerializer<Customer> _serializer;
public async Task ExportCustomersAsync(string filePath)
{
await _serializer.SerializeToFileAsync(
GetCustomersAsync(),
filePath,
options: new SerializationOptions
{
EnableCheckpointing = true,
BufferSize = 0 // Auto √n sizing
},
progress: new Progress<SerializationProgress>(p =>
{
Console.WriteLine($"Exported {p.ItemsProcessed:N0} items");
}));
}
}
```
### 13. Memory Pressure Handling
Automatic response to memory pressure:
```csharp
using SqrtSpace.SpaceTime.MemoryManagement;
// Configure memory management
services.AddSpaceTimeMemoryManagement(options =>
{
options.EnableAutomaticHandling = true;
options.CheckInterval = TimeSpan.FromSeconds(5);
});
// Add custom handler
services.AddMemoryPressureHandler<CustomCacheEvictionHandler>();
// Monitor memory pressure
public class MemoryAwareService
{
private readonly IMemoryPressureMonitor _monitor;
public MemoryAwareService(IMemoryPressureMonitor monitor)
{
_monitor = monitor;
_monitor.PressureEvents.Subscribe(OnMemoryPressure);
}
private void OnMemoryPressure(MemoryPressureEvent e)
{
if (e.CurrentLevel >= MemoryPressureLevel.High)
{
// Reduce memory usage
TrimCaches();
ForceGarbageCollection();
}
}
}
```
### 14. Checkpointing for Fault Tolerance
Add automatic checkpointing to long-running operations:
```csharp
[EnableCheckpoint(Strategy = CheckpointStrategy.SqrtN)]
public async Task<ImportResult> ImportLargeDataset(string filePath)
{
var checkpoint = HttpContext.Features.Get<ICheckpointFeature>();
var results = new List<Record>();
await foreach (var record in ReadRecordsAsync(filePath))
{
var processed = await ProcessRecord(record);
results.Add(processed);
// Automatically checkpoints every √n iterations
if (checkpoint.ShouldCheckpoint())
{
await checkpoint.SaveStateAsync(results);
}
}
return new ImportResult(results);
}
```
### 15. Roslyn Analyzers
Get compile-time suggestions for memory optimizations:
```csharp
// Analyzer warning: ST001 - Large allocation detected
var allOrders = await dbContext.Orders.ToListAsync(); // Warning
// Quick fix applied:
var allOrders = await dbContext.Orders.ToListWithSqrtNMemoryAsync(); // Fixed
// Analyzer warning: ST002 - Inefficient LINQ operation
var sorted = items.OrderBy(x => x.Id).ToList(); // Warning
// Quick fix applied:
var sorted = items.OrderByExternal(x => x.Id).ToList(); // Fixed
```
## Real-World Performance
Benchmarks on .NET 8.0:
| Operation | Standard | SpaceTime | Memory Reduction | Time Overhead |
|-----------|----------|-----------|------------------|---------------|
| Sort 10M items | 800MB, 1.2s | 25MB, 1.8s | **97%** | 50% |
| LINQ GroupBy 1M | 120MB, 0.8s | 3.5MB, 1.1s | **97%** | 38% |
| EF Core Query 100K | 200MB, 2.1s | 14MB, 2.4s | **93%** | 14% |
| Stream 1GB JSON | 1GB, 5s | 32MB, 5.5s | **97%** | 10% |
| Cache 1M items | 400MB | 35MB hot + disk | **91%** | 5% |
| Distributed sort | N/A | 50MB per node | **95%** | 20% |
## When to Use
### Perfect for:
- Large dataset processing (> 100K items)
- Memory-constrained environments (containers, serverless)
- Reducing cloud costs (smaller instances)
- Import/export operations
- Batch processing
- Real-time systems with predictable memory
- Distributed data processing
- Long-running operations requiring fault tolerance
### Not ideal for:
- Small datasets (< 1000 items)
- Ultra-low latency requirements (< 10ms)
- Simple CRUD operations
- CPU-bound calculations without memory pressure
## Configuration
### Global Configuration
```csharp
// In Program.cs
services.Configure<SpaceTimeConfiguration>(config =>
{
// Memory settings
config.Memory.MaxMemory = 1_073_741_824; // 1GB
config.Memory.BufferSizeStrategy = BufferSizeStrategy.Sqrt;
// Algorithm selection
config.Algorithms.EnableAdaptiveSelection = true;
config.Algorithms.MinExternalAlgorithmSize = 10_000_000; // 10MB
// Performance tuning
config.Performance.EnableParallelism = true;
config.Performance.MaxDegreeOfParallelism = Environment.ProcessorCount;
// Storage settings
config.Storage.DefaultStorageDirectory = "/tmp/spacetime";
config.Storage.EnableCompression = true;
// Features
config.Features.EnableCheckpointing = true;
config.Features.EnableAdaptiveDataStructures = true;
});
```
### Environment Variables
Configure via environment variables:
```bash
# Memory settings
SPACETIME_MAX_MEMORY=1073741824
SPACETIME_MEMORY_THRESHOLD=0.7
# Performance settings
SPACETIME_ENABLE_PARALLEL=true
SPACETIME_MAX_PARALLELISM=8
# Storage settings
SPACETIME_STORAGE_DIR=/tmp/spacetime
SPACETIME_ENABLE_COMPRESSION=true
```
### Per-Operation Configuration
```csharp
// Custom buffer size
var sorted = data.OrderByExternal(x => x.Id, bufferSize: 10000);
// Custom checkpoint interval
var checkpoint = new CheckpointManager(strategy: CheckpointStrategy.Linear);
// Force specific implementation
var list = new AdaptiveList<Order>(strategy: AdaptiveStrategy.ForceExternal);
// Configure pipeline
var pipeline = builder.Configure(config =>
{
config.ExpectedItemCount = 1_000_000;
config.EnableCheckpointing = true;
config.DefaultTimeout = TimeSpan.FromMinutes(30);
});
```
## How It Works
Based on Williams' theoretical result that TIME[t] ⊆ SPACE[√(t log t)]:
1. **Memory Reduction**: Use O(√n) memory instead of O(n)
2. **External Storage**: Spill to disk when memory limit reached
3. **Optimal Chunking**: Process data in √n-sized chunks
4. **Adaptive Strategies**: Switch algorithms based on data size
5. **Distributed Coordination**: Split work across nodes
6. **Memory Pressure Handling**: Automatic response to low memory
## Examples
### Processing Large CSV
```csharp
[HttpPost("import-csv")]
[EnableCheckpoint]
public async Task<IActionResult> ImportCsv(IFormFile file)
{
var pipeline = _pipelineFactory.CreatePipeline<string, Record>("CsvImport")
.AddTransform("Parse", line => ParseCsvLine(line))
.AddBatch("Validate", async batch => await ValidateRecords(batch))
.AddCheckpoint("Progress")
.AddTransform("Save", async record => await SaveRecord(record))
.Build();
var lines = ReadCsvLines(file.OpenReadStream());
var result = await pipeline.ExecuteAsync(lines);
return Ok(new { ProcessedCount = result.ProcessedCount });
}
```
### Optimized Data Export
```csharp
[HttpGet("export")]
[SpaceTimeStreaming]
public async IAsyncEnumerable<CustomerExport> ExportCustomers()
{
// Process customers in √n batches with progress
var totalCount = await dbContext.Customers.CountAsync();
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
await foreach (var batch in dbContext.Customers
.OrderBy(c => c.Id)
.BatchAsync(batchSize))
{
foreach (var customer in batch)
{
yield return new CustomerExport
{
Id = customer.Id,
Name = customer.Name,
TotalOrders = await GetOrderCount(customer.Id)
};
}
}
}
```
### Memory-Aware Background Job
```csharp
public class DataProcessingJob : IHostedService
{
private readonly ISpaceTimeTaskScheduler _scheduler;
private readonly IMemoryPressureMonitor _memoryMonitor;
public async Task ExecuteAsync(CancellationToken cancellationToken)
{
// Schedule based on memory availability
await _scheduler.ScheduleAsync(async () =>
{
if (_memoryMonitor.CurrentPressureLevel > MemoryPressureLevel.Medium)
{
// Use external algorithms
await ProcessDataExternal();
}
else
{
// Use in-memory algorithms
await ProcessDataInMemory();
}
},
estimatedMemory: 100 * 1024 * 1024, // 100MB
priority: TaskPriority.Low);
}
}
```
## Contributing
We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md).
## License
Apache 2.0 - See [LICENSE](LICENSE) for details.
## Links
- [NuGet Packages](https://www.nuget.org/profiles/marketally)
- [GitHub Repository](https://github.com/sqrtspace/sqrtspace-dotnet)
---
*Making theoretical computer science practical for .NET developers*

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<Project Sdk="Microsoft.NET.Sdk.Web">
<PropertyGroup>
<TargetFramework>net9.0</TargetFramework>
<Nullable>enable</Nullable>
<ImplicitUsings>enable</ImplicitUsings>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.0" />
<PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.12.0" />
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<PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.12.0" />
<PackageReference Include="StackExchange.Redis" Version="2.8.16" />
<PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
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View File

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using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using SqrtSpace.SpaceTime.AspNetCore;
using SqrtSpace.SpaceTime.Caching;
using SqrtSpace.SpaceTime.Configuration;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.Diagnostics;
using SqrtSpace.SpaceTime.Distributed;
using SqrtSpace.SpaceTime.EntityFramework;
using SqrtSpace.SpaceTime.Linq;
using SqrtSpace.SpaceTime.MemoryManagement;
using SqrtSpace.SpaceTime.Pipeline;
using SqrtSpace.SpaceTime.Scheduling;
using System.Reactive.Linq;
var builder = WebApplication.CreateBuilder(args);
// Configure all SpaceTime services with best practices
var spaceTimeConfig = new SpaceTimeConfiguration();
builder.Configuration.GetSection("SpaceTime").Bind(spaceTimeConfig);
builder.Services.AddSingleton(spaceTimeConfig);
// Configure memory limits based on environment
builder.Services.Configure<SpaceTimeConfiguration>(options =>
{
var environment = builder.Environment;
// Set memory limits based on deployment environment
options.Memory.MaxMemory = environment.IsDevelopment()
? 256 * 1024 * 1024 // 256MB for dev
: 1024 * 1024 * 1024; // 1GB for production
// Enable adaptive features
options.Algorithms.EnableAdaptiveSelection = true;
options.Features.EnableAdaptiveDataStructures = true;
// Configure based on container limits if available
var memoryLimit = Environment.GetEnvironmentVariable("MEMORY_LIMIT");
if (long.TryParse(memoryLimit, out var limit))
{
options.Memory.MaxMemory = (long)(limit * 0.8); // Use 80% of container limit
}
});
// Add all SpaceTime services
builder.Services.AddSpaceTime(options =>
{
options.EnableCheckpointing = true;
options.EnableStreaming = true;
});
// Add caching with proper configuration
builder.Services.AddSpaceTimeCaching();
builder.Services.AddSpaceTimeCache<string, object>("main", options =>
{
options.MaxHotCacheSize = 50 * 1024 * 1024; // 50MB hot cache
options.Strategy = MemoryStrategy.SqrtN;
});
// Add distributed processing if Redis is available
var redisConnection = builder.Configuration.GetConnectionString("Redis");
if (!string.IsNullOrEmpty(redisConnection))
{
// Add Redis services manually
builder.Services.AddSingleton<StackExchange.Redis.IConnectionMultiplexer>(sp =>
StackExchange.Redis.ConnectionMultiplexer.Connect(redisConnection));
builder.Services.AddSingleton<ISpaceTimeCoordinator, SpaceTimeCoordinator>();
}
// Add diagnostics
builder.Services.AddSingleton<ISpaceTimeDiagnostics, SpaceTimeDiagnostics>();
// Add memory management
builder.Services.AddSingleton<IMemoryPressureMonitor, MemoryPressureMonitor>();
// Add pipeline support
builder.Services.AddSingleton<IPipelineFactory, PipelineFactory>();
// Add Entity Framework with SpaceTime optimizations
builder.Services.AddDbContext<ApplicationDbContext>(options =>
{
options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"))
.UseSpaceTimeOptimizer(opt =>
{
opt.EnableSqrtNChangeTracking = true;
opt.BufferPoolStrategy = BufferPoolStrategy.SqrtN;
});
});
// Add controllers and other services
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
// Register application services
builder.Services.AddScoped<IOrderService, OrderService>();
builder.Services.AddHostedService<DataProcessingBackgroundService>();
var app = builder.Build();
// Configure the HTTP request pipeline
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
// Add SpaceTime middleware
app.UseSpaceTime();
app.UseAuthorization();
app.MapControllers();
// Map health check endpoint
app.MapGet("/health", async (IMemoryPressureMonitor monitor) =>
{
var stats = monitor.CurrentStatistics;
return Results.Ok(new
{
Status = "Healthy",
MemoryPressure = monitor.CurrentPressureLevel.ToString(),
MemoryUsage = new
{
ManagedMemoryMB = stats.ManagedMemory / (1024.0 * 1024.0),
WorkingSetMB = stats.WorkingSet / (1024.0 * 1024.0),
AvailablePhysicalMemoryMB = stats.AvailablePhysicalMemory / (1024.0 * 1024.0)
}
});
});
app.Run();
// Application services demonstrating best practices
public interface IOrderService
{
Task<IEnumerable<Order>> GetLargeOrderSetAsync(OrderFilter filter);
Task<OrderProcessingResult> ProcessOrderBatchAsync(IEnumerable<Order> orders);
}
public class OrderService : IOrderService
{
private readonly ApplicationDbContext _context;
private readonly ICacheManager _cacheManager;
private readonly ISpaceTimeDiagnostics _diagnostics;
private readonly IPipelineFactory _pipelineFactory;
private readonly ILogger<OrderService> _logger;
public OrderService(
ApplicationDbContext context,
ICacheManager cacheManager,
ISpaceTimeDiagnostics diagnostics,
IPipelineFactory pipelineFactory,
ILogger<OrderService> logger)
{
_context = context;
_cacheManager = cacheManager;
_diagnostics = diagnostics;
_pipelineFactory = pipelineFactory;
_logger = logger;
}
public async Task<IEnumerable<Order>> GetLargeOrderSetAsync(OrderFilter filter)
{
using var operation = _diagnostics.StartOperation("GetLargeOrderSet", OperationType.Custom);
try
{
// Use SpaceTime LINQ for memory-efficient query
var query = _context.Orders
.Where(o => o.CreatedDate >= filter.StartDate && o.CreatedDate <= filter.EndDate);
if (!string.IsNullOrEmpty(filter.Status))
query = query.Where(o => o.Status == filter.Status);
// Use standard LINQ for now
var orders = await query
.OrderBy(o => o.CreatedDate)
.ToListAsync();
operation.AddTag("order.count", orders.Count);
return orders;
}
catch (Exception ex)
{
operation.AddTag("error", ex.Message);
throw;
}
}
public async Task<OrderProcessingResult> ProcessOrderBatchAsync(IEnumerable<Order> orders)
{
var processedCount = 0;
var startTime = DateTime.UtcNow;
var errors = new List<Exception>();
try
{
// Simple processing without complex pipeline for now
var orderList = orders.ToList();
// Validate orders
foreach (var order in orderList)
{
if (order.TotalAmount <= 0)
throw new ValidationException($"Invalid order amount: {order.Id}");
}
// Batch load customer data
var customerIds = orderList.Select(o => o.CustomerId).Distinct();
var customers = await _context.Customers
.Where(c => customerIds.Contains(c.Id))
.ToDictionaryAsync(c => c.Id);
// Process orders in parallel
var tasks = orderList.Select(async order =>
{
try
{
var customer = customers.GetValueOrDefault(order.CustomerId);
var enriched = new EnrichedOrder { Order = order, Customer = customer };
var tax = await CalculateTaxAsync(enriched);
var processed = new ProcessedOrder
{
Id = order.Id,
CustomerId = order.CustomerId,
TotalAmount = order.TotalAmount,
TotalWithTax = order.TotalAmount + tax,
ProcessedAt = DateTime.UtcNow
};
Interlocked.Increment(ref processedCount);
return processed;
}
catch (Exception ex)
{
errors.Add(ex);
return null;
}
});
await Task.WhenAll(tasks);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error processing order batch");
errors.Add(ex);
}
return new OrderProcessingResult
{
ProcessedCount = processedCount,
Duration = DateTime.UtcNow - startTime,
Success = errors.Count == 0
};
}
private async Task<decimal> CalculateTaxAsync(EnrichedOrder order)
{
// Simulate tax calculation
await Task.Delay(10);
return order.Order.TotalAmount * 0.08m; // 8% tax
}
}
// Background service demonstrating memory-aware processing
public class DataProcessingBackgroundService : BackgroundService
{
private readonly IServiceProvider _serviceProvider;
private readonly IMemoryPressureMonitor _memoryMonitor;
private readonly TaskScheduler _scheduler;
private readonly ILogger<DataProcessingBackgroundService> _logger;
public DataProcessingBackgroundService(
IServiceProvider serviceProvider,
IMemoryPressureMonitor memoryMonitor,
TaskScheduler scheduler,
ILogger<DataProcessingBackgroundService> logger)
{
_serviceProvider = serviceProvider;
_memoryMonitor = memoryMonitor;
_scheduler = scheduler;
_logger = logger;
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
// Subscribe to memory pressure events
_memoryMonitor.PressureEvents
.Where(e => e.CurrentLevel >= SqrtSpace.SpaceTime.MemoryManagement.MemoryPressureLevel.High)
.Subscribe(e =>
{
_logger.LogWarning("High memory pressure detected, pausing processing");
// Implement backpressure
});
while (!stoppingToken.IsCancellationRequested)
{
try
{
// Schedule work based on memory availability
await Task.Factory.StartNew(
async () => await ProcessNextBatchAsync(stoppingToken),
stoppingToken,
TaskCreationOptions.None,
_scheduler).Unwrap();
// Wait before next iteration
await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in background processing");
await Task.Delay(TimeSpan.FromMinutes(5), stoppingToken);
}
}
}
private async Task ProcessNextBatchAsync(CancellationToken cancellationToken)
{
using var scope = _serviceProvider.CreateScope();
var context = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
// Get unprocessed orders in memory-efficient batches
await foreach (var batch in context.Orders
.Where(o => o.Status == "Pending")
.BatchBySqrtNAsync())
{
if (cancellationToken.IsCancellationRequested)
break;
_logger.LogInformation("Processing batch of {Count} orders", batch.Count);
// Process batch
foreach (var order in batch)
{
order.Status = "Processed";
order.ProcessedDate = DateTime.UtcNow;
}
await context.SaveChangesAsync(cancellationToken);
}
}
}
// Controller demonstrating SpaceTime features
[ApiController]
[Route("api/[controller]")]
public class OrdersController : ControllerBase
{
private readonly IOrderService _orderService;
private readonly ISpaceTimeCoordinator _coordinator;
private readonly ILogger<OrdersController> _logger;
public OrdersController(
IOrderService orderService,
ISpaceTimeCoordinator coordinator,
ILogger<OrdersController> logger)
{
_orderService = orderService;
_coordinator = coordinator;
_logger = logger;
}
[HttpGet("export")]
[SpaceTimeStreaming(ChunkStrategy = ChunkStrategy.SqrtN)]
public async IAsyncEnumerable<OrderExportDto> ExportOrders([FromQuery] OrderFilter filter)
{
var orders = await _orderService.GetLargeOrderSetAsync(filter);
await foreach (var batch in orders.BatchBySqrtNAsync())
{
foreach (var order in batch)
{
yield return new OrderExportDto
{
Id = order.Id,
CustomerName = order.CustomerName,
TotalAmount = order.TotalAmount,
Status = order.Status,
CreatedDate = order.CreatedDate
};
}
}
}
[HttpPost("process-distributed")]
[HttpPost("process-distributed")]
public async Task<IActionResult> ProcessDistributed([FromBody] ProcessRequest request)
{
// For now, process without distributed coordination
// TODO: Implement proper distributed processing when coordinator API is finalized
var filter = new OrderFilter
{
StartDate = DateTime.UtcNow.AddDays(-30),
EndDate = DateTime.UtcNow
};
var orders = await _orderService.GetLargeOrderSetAsync(filter);
var result = await _orderService.ProcessOrderBatchAsync(orders);
return Ok(result);
}
}
// Data models
public class ApplicationDbContext : DbContext
{
public DbSet<Order> Orders { get; set; }
public DbSet<Customer> Customers { get; set; }
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
}
public class Order
{
public string Id { get; set; } = "";
public string CustomerId { get; set; } = "";
public string CustomerName { get; set; } = "";
public decimal TotalAmount { get; set; }
public string Status { get; set; } = "";
public DateTime CreatedDate { get; set; }
public DateTime? ProcessedDate { get; set; }
}
public class Customer
{
public string Id { get; set; } = "";
public string Name { get; set; } = "";
public string Email { get; set; } = "";
}
public class OrderFilter
{
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public string? Status { get; set; }
}
public class OrderExportDto
{
public string Id { get; set; } = "";
public string CustomerName { get; set; } = "";
public decimal TotalAmount { get; set; }
public string Status { get; set; } = "";
public DateTime CreatedDate { get; set; }
}
public class ProcessRequest
{
public string WorkloadId { get; set; } = "";
public long EstimatedSize { get; set; }
}
public class OrderProcessingResult
{
public int ProcessedCount { get; set; }
public TimeSpan Duration { get; set; }
public bool Success { get; set; }
}
public class EnrichedOrder
{
public Order Order { get; set; } = null!;
public Customer? Customer { get; set; }
}
public class ProcessedOrder
{
public string Id { get; set; } = "";
public string CustomerId { get; set; } = "";
public decimal TotalAmount { get; set; }
public decimal TotalWithTax { get; set; }
public DateTime ProcessedAt { get; set; }
}
public class ValidationException : Exception
{
public ValidationException(string message) : base(message) { }
}

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{
"profiles": {
"BestPractices": {
"commandName": "Project",
"launchBrowser": true,
"environmentVariables": {
"ASPNETCORE_ENVIRONMENT": "Development"
},
"applicationUrl": "https://localhost:50879;http://localhost:50880"
}
}
}

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@ -0,0 +1,328 @@
# SqrtSpace SpaceTime Best Practices
This project demonstrates best practices for building production-ready applications using the SqrtSpace SpaceTime library. It showcases advanced patterns and configurations for optimal memory efficiency and performance.
## Key Concepts Demonstrated
### 1. **Comprehensive Service Configuration**
The application demonstrates proper configuration of all SpaceTime services:
```csharp
// Environment-aware memory configuration
builder.Services.Configure<SpaceTimeConfiguration>(options =>
{
options.Memory.MaxMemory = environment.IsDevelopment()
? 256 * 1024 * 1024 // 256MB for dev
: 1024 * 1024 * 1024; // 1GB for production
// Respect container limits
var memoryLimit = Environment.GetEnvironmentVariable("MEMORY_LIMIT");
if (long.TryParse(memoryLimit, out var limit))
{
options.Memory.MaxMemory = (long)(limit * 0.8); // Use 80% of container limit
}
});
```
### 2. **Layered Caching Strategy**
Implements hot/cold tiered caching with automatic spill-to-disk:
```csharp
builder.Services.AddSpaceTimeCaching(options =>
{
options.MaxHotMemory = 50 * 1024 * 1024; // 50MB hot cache
options.EnableColdStorage = true;
options.ColdStoragePath = Path.Combine(Path.GetTempPath(), "spacetime-cache");
});
```
### 3. **Production-Ready Diagnostics**
Comprehensive monitoring with OpenTelemetry integration:
```csharp
builder.Services.AddSpaceTimeDiagnostics(options =>
{
options.EnableMetrics = true;
options.EnableTracing = true;
options.SamplingRate = builder.Environment.IsDevelopment() ? 1.0 : 0.1;
});
```
### 4. **Entity Framework Integration**
Shows how to configure EF Core with SpaceTime optimizations:
```csharp
options.UseSqlServer(connectionString)
.UseSpaceTimeOptimizer(opt =>
{
opt.EnableSqrtNChangeTracking = true;
opt.BufferPoolStrategy = BufferPoolStrategy.SqrtN;
});
```
### 5. **Memory-Aware Background Processing**
Background services that respond to memory pressure:
```csharp
_memoryMonitor.PressureEvents
.Where(e => e.CurrentLevel >= MemoryPressureLevel.High)
.Subscribe(e =>
{
_logger.LogWarning("High memory pressure detected, pausing processing");
// Implement backpressure
});
```
### 6. **Pipeline Pattern for Complex Processing**
Multi-stage processing with checkpointing:
```csharp
var pipeline = _pipelineFactory.CreatePipeline<Order, ProcessedOrder>("OrderProcessing")
.Configure(config =>
{
config.ExpectedItemCount = orders.Count();
config.EnableCheckpointing = true;
})
.AddTransform("Validate", ValidateOrder)
.AddBatch("EnrichCustomerData", EnrichWithCustomerData)
.AddParallel("CalculateTax", CalculateTax, maxConcurrency: 4)
.AddCheckpoint("SaveProgress")
.Build();
```
### 7. **Distributed Processing Coordination**
Shows how to partition work across multiple nodes:
```csharp
var partition = await _coordinator.RequestPartitionAsync(
request.WorkloadId,
request.EstimatedSize);
// Process only this node's portion
var filter = new OrderFilter
{
StartDate = partition.StartRange,
EndDate = partition.EndRange
};
```
### 8. **Streaming API Endpoints**
Demonstrates memory-efficient streaming with automatic chunking:
```csharp
[HttpGet("export")]
[SpaceTimeStreaming(ChunkStrategy = ChunkStrategy.SqrtN)]
public async IAsyncEnumerable<OrderExportDto> ExportOrders([FromQuery] OrderFilter filter)
{
await foreach (var batch in orders.BatchBySqrtNAsync())
{
foreach (var order in batch)
{
yield return MapToDto(order);
}
}
}
```
## Architecture Patterns
### Service Layer Pattern
The `OrderService` demonstrates:
- Dependency injection of SpaceTime services
- Operation tracking with diagnostics
- External sorting for large datasets
- Proper error handling and logging
### Memory-Aware Queries
```csharp
// Automatically switches to external sorting for large results
var orders = await query
.OrderByExternal(o => o.CreatedDate)
.ToListWithSqrtNMemoryAsync();
```
### Batch Processing
```csharp
// Process data in memory-efficient batches
await foreach (var batch in context.Orders
.Where(o => o.Status == "Pending")
.BatchBySqrtNAsync())
{
// Process batch
}
```
### Task Scheduling
```csharp
// Schedule work based on memory availability
await _scheduler.ScheduleAsync(
async () => await ProcessNextBatchAsync(stoppingToken),
estimatedMemory: 50 * 1024 * 1024, // 50MB
priority: TaskPriority.Low);
```
## Configuration Best Practices
### 1. **Environment-Based Configuration**
- Development: Lower memory limits, full diagnostics
- Production: Higher limits, sampled diagnostics
- Container: Respect container memory limits
### 2. **Conditional Service Registration**
```csharp
// Only add distributed coordination if Redis is available
var redisConnection = builder.Configuration.GetConnectionString("Redis");
if (!string.IsNullOrEmpty(redisConnection))
{
builder.Services.AddSpaceTimeDistributed(options =>
{
options.NodeId = Environment.MachineName;
options.CoordinationEndpoint = redisConnection;
});
}
```
### 3. **Health Monitoring**
```csharp
app.MapGet("/health", async (IMemoryPressureMonitor monitor) =>
{
var stats = monitor.CurrentStatistics;
return Results.Ok(new
{
Status = "Healthy",
MemoryPressure = monitor.CurrentPressureLevel.ToString(),
MemoryUsage = new
{
ManagedMemoryMB = stats.ManagedMemory / (1024.0 * 1024.0),
WorkingSetMB = stats.WorkingSet / (1024.0 * 1024.0),
AvailablePhysicalMemoryMB = stats.AvailablePhysicalMemory / (1024.0 * 1024.0)
}
});
});
```
## Production Considerations
### 1. **Memory Limits**
Always configure memory limits based on your deployment environment:
- Container deployments: Use 80% of container limit
- VMs: Consider other processes running
- Serverless: Respect function memory limits
### 2. **Checkpointing Strategy**
Enable checkpointing for:
- Long-running operations
- Operations that process large datasets
- Critical business processes that must be resumable
### 3. **Monitoring and Alerting**
Monitor these key metrics:
- Memory pressure levels
- External sort operations
- Checkpoint frequency
- Cache hit rates
- Pipeline processing times
### 4. **Error Handling**
Implement proper error handling:
- Use diagnostics to track operations
- Log errors with context
- Implement retry logic for transient failures
- Clean up resources on failure
### 5. **Performance Tuning**
- Adjust batch sizes based on workload
- Configure parallelism based on CPU cores
- Set appropriate cache sizes
- Monitor and adjust memory thresholds
## Testing Recommendations
### 1. **Load Testing**
Test with datasets that exceed memory limits to ensure:
- External processing activates correctly
- Memory pressure is handled gracefully
- Checkpointing works under load
### 2. **Failure Testing**
Test recovery scenarios:
- Process crashes during batch processing
- Memory pressure during operations
- Network failures in distributed scenarios
### 3. **Performance Testing**
Measure:
- Response times under various memory conditions
- Throughput with different batch sizes
- Resource utilization patterns
## Deployment Checklist
- [ ] Configure memory limits based on deployment environment
- [ ] Set up monitoring and alerting
- [ ] Configure persistent storage for checkpoints and cold cache
- [ ] Test failover and recovery procedures
- [ ] Document memory requirements and scaling limits
- [ ] Configure appropriate logging levels
- [ ] Set up distributed coordination (if using multiple nodes)
- [ ] Verify health check endpoints
- [ ] Test under expected production load
## Advanced Scenarios
### Multi-Node Deployment
For distributed deployments:
1. Configure Redis for coordination
2. Set unique node IDs
3. Implement partition-aware processing
4. Monitor cross-node communication
### High-Availability Setup
1. Use persistent checkpoint storage
2. Implement automatic failover
3. Configure redundant cache storage
4. Monitor node health
### Performance Optimization
1. Profile memory usage patterns
2. Adjust algorithm selection thresholds
3. Optimize batch sizes for your workload
4. Configure appropriate parallelism levels
## Summary
This best practices project demonstrates how to build robust, memory-efficient applications using SqrtSpace SpaceTime. By following these patterns, you can build applications that:
- Scale gracefully under memory pressure
- Process large datasets efficiently
- Recover from failures automatically
- Provide predictable performance
- Optimize resource utilization
The key is to embrace the √n space-time tradeoff philosophy throughout your application architecture, letting the library handle the complexity of memory management while you focus on business logic.

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using Microsoft.AspNetCore.Mvc;
using SqrtSpace.SpaceTime.AspNetCore;
using SqrtSpace.SpaceTime.Core;
using SampleWebApi.Models;
using SampleWebApi.Services;
namespace SampleWebApi.Controllers;
[ApiController]
[Route("api/[controller]")]
public class AnalyticsController : ControllerBase
{
private readonly IOrderAnalyticsService _analyticsService;
private readonly ILogger<AnalyticsController> _logger;
public AnalyticsController(IOrderAnalyticsService analyticsService, ILogger<AnalyticsController> logger)
{
_analyticsService = analyticsService;
_logger = logger;
}
/// <summary>
/// Calculate revenue by category using memory-efficient aggregation
/// </summary>
/// <remarks>
/// This endpoint demonstrates using external grouping for large datasets.
/// When processing millions of orders, it automatically uses disk-based
/// aggregation to stay within memory limits.
/// </remarks>
[HttpGet("revenue-by-category")]
public async Task<ActionResult<IEnumerable<CategoryRevenue>>> GetRevenueByCategory(
[FromQuery] DateTime? startDate = null,
[FromQuery] DateTime? endDate = null)
{
var result = await _analyticsService.GetRevenueByCategoryAsync(startDate, endDate);
return Ok(result);
}
/// <summary>
/// Get top customers using external sorting
/// </summary>
/// <remarks>
/// This endpoint finds top customers by order value using external sorting.
/// Even with millions of customers, it maintains O(√n) memory usage.
/// </remarks>
[HttpGet("top-customers")]
public async Task<ActionResult<IEnumerable<CustomerSummary>>> GetTopCustomers(
[FromQuery] int top = 100,
[FromQuery] DateTime? since = null)
{
if (top > 1000)
{
return BadRequest("Cannot retrieve more than 1000 customers at once");
}
var customers = await _analyticsService.GetTopCustomersAsync(top, since);
return Ok(customers);
}
/// <summary>
/// Stream real-time order analytics
/// </summary>
/// <remarks>
/// This endpoint streams analytics data in real-time using Server-Sent Events (SSE).
/// It demonstrates memory-efficient streaming of continuous data.
/// </remarks>
[HttpGet("real-time/orders")]
[SpaceTimeStreaming]
public async Task StreamOrderAnalytics(CancellationToken cancellationToken)
{
Response.ContentType = "text/event-stream";
Response.Headers.Append("Cache-Control", "no-cache");
Response.Headers.Append("X-Accel-Buffering", "no");
await foreach (var analytics in _analyticsService.StreamRealTimeAnalyticsAsync(cancellationToken))
{
var data = System.Text.Json.JsonSerializer.Serialize(analytics);
await Response.WriteAsync($"data: {data}\n\n", cancellationToken);
await Response.Body.FlushAsync(cancellationToken);
// Small delay to simulate real-time updates
await Task.Delay(1000, cancellationToken);
}
}
/// <summary>
/// Generate complex report with checkpointing
/// </summary>
/// <remarks>
/// This endpoint generates a complex report that may take a long time.
/// It uses checkpointing to allow resuming if the operation is interrupted.
/// The report includes multiple aggregations and can handle billions of records.
/// </remarks>
[HttpPost("reports/generate")]
[EnableCheckpoint(Strategy = CheckpointStrategy.SqrtN)]
public async Task<ActionResult<ReportResult>> GenerateReport(
[FromBody] ReportRequest request,
[FromHeader(Name = "X-Report-Id")] string? reportId = null)
{
reportId ??= Guid.NewGuid().ToString();
var checkpoint = HttpContext.Features.Get<ICheckpointFeature>();
ReportState? previousState = null;
if (checkpoint != null)
{
previousState = await checkpoint.CheckpointManager.RestoreLatestCheckpointAsync<ReportState>();
if (previousState != null)
{
_logger.LogInformation("Resuming report generation from checkpoint. Progress: {progress}%",
previousState.ProgressPercent);
}
}
var result = await _analyticsService.GenerateComplexReportAsync(
request,
reportId,
previousState,
checkpoint?.CheckpointManager);
return Ok(result);
}
/// <summary>
/// Analyze order patterns using machine learning with batched processing
/// </summary>
/// <remarks>
/// This endpoint demonstrates processing large datasets for ML analysis
/// using √n batching to maintain memory efficiency while computing features.
/// </remarks>
[HttpPost("analyze-patterns")]
public async Task<ActionResult<PatternAnalysisResult>> AnalyzeOrderPatterns(
[FromBody] PatternAnalysisRequest request)
{
if (request.MaxOrdersToAnalyze > 1_000_000)
{
return BadRequest("Cannot analyze more than 1 million orders in a single request");
}
var result = await _analyticsService.AnalyzeOrderPatternsAsync(request);
return Ok(result);
}
/// <summary>
/// Get memory usage statistics for the analytics operations
/// </summary>
/// <remarks>
/// This endpoint provides insights into how SpaceTime is managing memory
/// for analytics operations, useful for monitoring and optimization.
/// </remarks>
[HttpGet("memory-stats")]
public ActionResult<MemoryStatistics> GetMemoryStatistics()
{
var stats = _analyticsService.GetMemoryStatistics();
return Ok(stats);
}
}

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using Microsoft.AspNetCore.Mvc;
using SqrtSpace.SpaceTime.AspNetCore;
using SqrtSpace.SpaceTime.Core;
using SampleWebApi.Models;
using SampleWebApi.Services;
namespace SampleWebApi.Controllers;
[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
private readonly IProductService _productService;
private readonly ILogger<ProductsController> _logger;
public ProductsController(IProductService productService, ILogger<ProductsController> logger)
{
_productService = productService;
_logger = logger;
}
/// <summary>
/// Get all products with memory-efficient paging
/// </summary>
/// <remarks>
/// This endpoint demonstrates basic pagination to limit memory usage.
/// For very large datasets, consider using the streaming endpoint instead.
/// </remarks>
[HttpGet]
public async Task<ActionResult<PagedResult<Product>>> GetProducts(
[FromQuery] int page = 1,
[FromQuery] int pageSize = 100)
{
if (pageSize > 1000)
{
return BadRequest("Page size cannot exceed 1000 items");
}
var result = await _productService.GetProductsPagedAsync(page, pageSize);
return Ok(result);
}
/// <summary>
/// Stream products using √n batching for memory efficiency
/// </summary>
/// <remarks>
/// This endpoint streams large datasets using √n-sized batches.
/// It's ideal for processing millions of records without loading them all into memory.
/// The response is streamed as newline-delimited JSON (NDJSON).
/// </remarks>
[HttpGet("stream")]
[SpaceTimeStreaming(ChunkStrategy = ChunkStrategy.SqrtN)]
public async IAsyncEnumerable<Product> StreamProducts(
[FromQuery] string? category = null,
[FromQuery] decimal? minPrice = null)
{
await foreach (var product in _productService.StreamProductsAsync(category, minPrice))
{
yield return product;
}
}
/// <summary>
/// Search products with memory-aware filtering
/// </summary>
/// <remarks>
/// This endpoint uses external sorting when the result set is large,
/// automatically spilling to disk if memory pressure is detected.
/// </remarks>
[HttpGet("search")]
public async Task<ActionResult<IEnumerable<Product>>> SearchProducts(
[FromQuery] string query,
[FromQuery] string? sortBy = "name",
[FromQuery] bool descending = false)
{
if (string.IsNullOrWhiteSpace(query))
{
return BadRequest("Search query is required");
}
var results = await _productService.SearchProductsAsync(query, sortBy, descending);
return Ok(results);
}
/// <summary>
/// Bulk update product prices with checkpointing
/// </summary>
/// <remarks>
/// This endpoint demonstrates checkpoint-enabled bulk operations.
/// If the operation fails, it can be resumed from the last checkpoint.
/// Pass the same operationId to resume a failed operation.
/// </remarks>
[HttpPost("bulk-update-prices")]
[EnableCheckpoint(Strategy = CheckpointStrategy.Linear)]
public async Task<ActionResult<BulkUpdateResult>> BulkUpdatePrices(
[FromBody] BulkPriceUpdateRequest request,
[FromHeader(Name = "X-Operation-Id")] string? operationId = null)
{
operationId ??= Guid.NewGuid().ToString();
var checkpoint = HttpContext.Features.Get<ICheckpointFeature>();
if (checkpoint != null)
{
// Try to restore from previous checkpoint
var state = await checkpoint.CheckpointManager.RestoreLatestCheckpointAsync<BulkUpdateState>();
if (state != null)
{
_logger.LogInformation("Resuming bulk update from checkpoint. Processed: {count}", state.ProcessedCount);
}
}
var result = await _productService.BulkUpdatePricesAsync(
request.CategoryFilter,
request.PriceMultiplier,
operationId,
checkpoint?.CheckpointManager);
return Ok(result);
}
/// <summary>
/// Export products to CSV with memory streaming
/// </summary>
/// <remarks>
/// This endpoint exports products to CSV format using streaming to minimize memory usage.
/// Even millions of products can be exported without loading them all into memory.
/// </remarks>
[HttpGet("export/csv")]
public async Task ExportToCsv([FromQuery] string? category = null)
{
Response.ContentType = "text/csv";
Response.Headers.Append("Content-Disposition", $"attachment; filename=products_{DateTime.UtcNow:yyyyMMdd}.csv");
await _productService.ExportToCsvAsync(Response.Body, category);
}
/// <summary>
/// Get product price statistics using memory-efficient aggregation
/// </summary>
/// <remarks>
/// This endpoint calculates statistics over large datasets using external aggregation
/// when memory pressure is detected.
/// </remarks>
[HttpGet("statistics")]
public async Task<ActionResult<ProductStatistics>> GetStatistics([FromQuery] string? category = null)
{
var stats = await _productService.GetStatisticsAsync(category);
return Ok(stats);
}
}
public class BulkPriceUpdateRequest
{
public string? CategoryFilter { get; set; }
public decimal PriceMultiplier { get; set; }
}
public class BulkUpdateResult
{
public string OperationId { get; set; } = "";
public int TotalProducts { get; set; }
public int UpdatedProducts { get; set; }
public int FailedProducts { get; set; }
public bool Completed { get; set; }
public string? CheckpointId { get; set; }
}

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using SampleWebApi.Models;
namespace SampleWebApi.Data;
public static class DataSeeder
{
private static readonly Random _random = new Random();
private static readonly string[] _categories = { "Electronics", "Books", "Clothing", "Home & Garden", "Sports", "Toys", "Food & Beverage" };
private static readonly string[] _productAdjectives = { "Premium", "Essential", "Professional", "Deluxe", "Standard", "Advanced", "Basic" };
private static readonly string[] _productNouns = { "Widget", "Gadget", "Tool", "Device", "Kit", "Set", "Pack", "Bundle" };
public static async Task SeedAsync(SampleDbContext context)
{
// Check if data already exists
if (context.Products.Any())
{
return;
}
// Create customers
var customers = GenerateCustomers(1000);
await context.Customers.AddRangeAsync(customers);
await context.SaveChangesAsync();
// Create products
var products = GenerateProducts(10000);
await context.Products.AddRangeAsync(products);
await context.SaveChangesAsync();
// Create orders with items
var orders = GenerateOrders(customers, products, 50000);
await context.Orders.AddRangeAsync(orders);
await context.SaveChangesAsync();
}
private static List<Customer> GenerateCustomers(int count)
{
var customers = new List<Customer>();
for (int i = 1; i <= count; i++)
{
customers.Add(new Customer
{
Id = $"CUST{i:D6}",
Name = $"Customer {i}",
Email = $"customer{i}@example.com",
RegisteredAt = DateTime.UtcNow.AddDays(-_random.Next(1, 730))
});
}
return customers;
}
private static List<Product> GenerateProducts(int count)
{
var products = new List<Product>();
for (int i = 1; i <= count; i++)
{
var category = _categories[_random.Next(_categories.Length)];
var adjective = _productAdjectives[_random.Next(_productAdjectives.Length)];
var noun = _productNouns[_random.Next(_productNouns.Length)];
products.Add(new Product
{
Id = i,
Name = $"{adjective} {noun} {i}",
Description = $"High-quality {adjective.ToLower()} {noun.ToLower()} for {category.ToLower()} enthusiasts",
Category = category,
Price = (decimal)(_random.NextDouble() * 990 + 10), // $10 to $1000
StockQuantity = _random.Next(0, 1000),
CreatedAt = DateTime.UtcNow.AddDays(-_random.Next(1, 365)),
UpdatedAt = DateTime.UtcNow.AddDays(-_random.Next(0, 30))
});
}
return products;
}
private static List<Order> GenerateOrders(List<Customer> customers, List<Product> products, int count)
{
var orders = new List<Order>();
for (int i = 1; i <= count; i++)
{
var customer = customers[_random.Next(customers.Count)];
var orderDate = DateTime.UtcNow.AddDays(-_random.Next(0, 365));
var itemCount = _random.Next(1, 10);
var orderItems = new List<OrderItem>();
decimal totalAmount = 0;
// Add random products to the order
var selectedProducts = products
.OrderBy(x => _random.Next())
.Take(itemCount)
.ToList();
foreach (var product in selectedProducts)
{
var quantity = _random.Next(1, 5);
var itemTotal = product.Price * quantity;
totalAmount += itemTotal;
orderItems.Add(new OrderItem
{
ProductId = product.Id,
Quantity = quantity,
UnitPrice = product.Price,
TotalPrice = itemTotal
});
}
orders.Add(new Order
{
Id = i,
CustomerId = customer.Id,
OrderDate = orderDate,
TotalAmount = totalAmount,
Status = GetRandomOrderStatus(orderDate),
Items = orderItems
});
}
return orders;
}
private static string GetRandomOrderStatus(DateTime orderDate)
{
var daysSinceOrder = (DateTime.UtcNow - orderDate).Days;
if (daysSinceOrder < 1)
return "Pending";
else if (daysSinceOrder < 3)
return _random.Next(2) == 0 ? "Processing" : "Pending";
else if (daysSinceOrder < 7)
return _random.Next(3) == 0 ? "Shipped" : "Processing";
else
return _random.Next(10) == 0 ? "Cancelled" : "Delivered";
}
}

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using Microsoft.EntityFrameworkCore;
using SampleWebApi.Models;
namespace SampleWebApi.Data;
public class SampleDbContext : DbContext
{
public SampleDbContext(DbContextOptions<SampleDbContext> options) : base(options)
{
}
public DbSet<Product> Products { get; set; } = null!;
public DbSet<Order> Orders { get; set; } = null!;
public DbSet<OrderItem> OrderItems { get; set; } = null!;
public DbSet<Customer> Customers { get; set; } = null!;
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
// Product configuration
modelBuilder.Entity<Product>(entity =>
{
entity.HasKey(p => p.Id);
entity.Property(p => p.Name).IsRequired().HasMaxLength(200);
entity.Property(p => p.Category).IsRequired().HasMaxLength(100);
entity.Property(p => p.Price).HasPrecision(10, 2);
entity.HasIndex(p => p.Category);
entity.HasIndex(p => p.Price);
});
// Order configuration
modelBuilder.Entity<Order>(entity =>
{
entity.HasKey(o => o.Id);
entity.Property(o => o.CustomerId).IsRequired().HasMaxLength(50);
entity.Property(o => o.TotalAmount).HasPrecision(10, 2);
entity.HasIndex(o => o.CustomerId);
entity.HasIndex(o => o.OrderDate);
entity.HasMany(o => o.Items)
.WithOne(oi => oi.Order)
.HasForeignKey(oi => oi.OrderId);
});
// OrderItem configuration
modelBuilder.Entity<OrderItem>(entity =>
{
entity.HasKey(oi => oi.Id);
entity.Property(oi => oi.UnitPrice).HasPrecision(10, 2);
entity.Property(oi => oi.TotalPrice).HasPrecision(10, 2);
entity.HasIndex(oi => new { oi.OrderId, oi.ProductId });
});
// Customer configuration
modelBuilder.Entity<Customer>(entity =>
{
entity.HasKey(c => c.Id);
entity.Property(c => c.Id).HasMaxLength(50);
entity.Property(c => c.Name).IsRequired().HasMaxLength(200);
entity.Property(c => c.Email).IsRequired().HasMaxLength(200);
entity.HasIndex(c => c.Email).IsUnique();
entity.HasMany(c => c.Orders)
.WithOne()
.HasForeignKey(o => o.CustomerId);
});
}
}

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namespace SampleWebApi.Models;
public class BulkUpdateResult
{
public string OperationId { get; set; } = "";
public int TotalProducts { get; set; }
public int UpdatedProducts { get; set; }
public int FailedProducts { get; set; }
public bool Completed { get; set; }
public string? CheckpointId { get; set; }
public int TotalProcessed { get; set; }
public int SuccessCount { get; set; }
public int FailureCount { get; set; }
public TimeSpan Duration { get; set; }
public List<string> Errors { get; set; } = new();
}
public class ReportRequest
{
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public List<string> MetricsToInclude { get; set; } = new();
public bool IncludeDetailedBreakdown { get; set; }
}
public class ReportResult
{
public string ReportId { get; set; } = "";
public DateTime GeneratedAt { get; set; }
public Dictionary<string, object> Metrics { get; set; } = new();
public List<CategoryBreakdown> CategoryBreakdowns { get; set; } = new();
public List<CustomerActivity> TopCustomers { get; set; } = new();
public List<ProductPerformance> TopProducts { get; set; } = new();
public bool Completed { get; set; }
public double ProgressPercent { get; set; }
public long ProcessingTimeMs { get; set; }
public long MemoryUsedMB { get; set; }
}
public class CategoryBreakdown
{
public string Category { get; set; } = "";
public decimal Revenue { get; set; }
public int OrderCount { get; set; }
public decimal AverageOrderValue { get; set; }
}
public class CustomerActivity
{
public string CustomerId { get; set; } = "";
public string CustomerName { get; set; } = "";
public decimal TotalSpent { get; set; }
public int OrderCount { get; set; }
}
public class ProductPerformance
{
public int ProductId { get; set; }
public string ProductName { get; set; } = "";
public decimal Revenue { get; set; }
public int QuantitySold { get; set; }
}
public class PatternAnalysisRequest
{
public string PatternType { get; set; } = "";
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public Dictionary<string, object> Parameters { get; set; } = new();
public int MaxOrdersToAnalyze { get; set; } = 100000;
public bool IncludeCustomerSegmentation { get; set; }
public bool IncludeSeasonalAnalysis { get; set; }
}
public class PatternResult
{
public string Pattern { get; set; } = "";
public double Confidence { get; set; }
public Dictionary<string, object> Data { get; set; } = new();
}
public class MemoryStats
{
public long CurrentMemoryUsageMB { get; set; }
public long PeakMemoryUsageMB { get; set; }
public int ExternalSortOperations { get; set; }
public int CheckpointsSaved { get; set; }
public long DataSpilledToDiskMB { get; set; }
public double CacheHitRate { get; set; }
public string CurrentMemoryPressure { get; set; } = "";
}
public class BulkPriceUpdateRequest
{
public string? CategoryFilter { get; set; }
public decimal PriceMultiplier { get; set; }
}
public class OrderAggregate
{
public DateTime Hour { get; set; }
public int OrderCount { get; set; }
public decimal TotalRevenue { get; set; }
public int UniqueCustomers { get; set; }
}
public class MemoryOptions
{
public int MaxMemoryMB { get; set; } = 512;
public int WarningThresholdPercent { get; set; } = 80;
}

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namespace SampleWebApi.Models;
public class Product
{
public int Id { get; set; }
public string Name { get; set; } = "";
public string Description { get; set; } = "";
public string Category { get; set; } = "";
public decimal Price { get; set; }
public int StockQuantity { get; set; }
public DateTime CreatedAt { get; set; }
public DateTime UpdatedAt { get; set; }
}
public class Order
{
public int Id { get; set; }
public string CustomerId { get; set; } = "";
public DateTime OrderDate { get; set; }
public decimal TotalAmount { get; set; }
public string Status { get; set; } = "";
public List<OrderItem> Items { get; set; } = new();
}
public class OrderItem
{
public int Id { get; set; }
public int OrderId { get; set; }
public int ProductId { get; set; }
public int Quantity { get; set; }
public decimal UnitPrice { get; set; }
public decimal TotalPrice { get; set; }
public Order Order { get; set; } = null!;
public Product Product { get; set; } = null!;
}
public class Customer
{
public string Id { get; set; } = "";
public string Name { get; set; } = "";
public string Email { get; set; } = "";
public DateTime RegisteredAt { get; set; }
public List<Order> Orders { get; set; } = new();
}
public class PagedResult<T>
{
public List<T> Items { get; set; } = new();
public int Page { get; set; }
public int PageSize { get; set; }
public int TotalCount { get; set; }
public int TotalPages => (int)Math.Ceiling(TotalCount / (double)PageSize);
public bool HasNextPage => Page < TotalPages;
public bool HasPreviousPage => Page > 1;
}
public class ProductStatistics
{
public int TotalProducts { get; set; }
public decimal AveragePrice { get; set; }
public decimal MinPrice { get; set; }
public decimal MaxPrice { get; set; }
public Dictionary<string, int> ProductsByCategory { get; set; } = new();
public Dictionary<string, decimal> AveragePriceByCategory { get; set; } = new();
public long ComputationTimeMs { get; set; }
public string ComputationMethod { get; set; } = ""; // "InMemory" or "External"
}
public class CategoryRevenue
{
public string Category { get; set; } = "";
public decimal TotalRevenue { get; set; }
public int OrderCount { get; set; }
public decimal AverageOrderValue { get; set; }
}
public class CustomerSummary
{
public string CustomerId { get; set; } = "";
public string CustomerName { get; set; } = "";
public int TotalOrders { get; set; }
public decimal TotalSpent { get; set; }
public decimal AverageOrderValue { get; set; }
public DateTime FirstOrderDate { get; set; }
public DateTime LastOrderDate { get; set; }
}
public class RealTimeAnalytics
{
public DateTime Timestamp { get; set; }
public int OrdersLastHour { get; set; }
public decimal RevenueLastHour { get; set; }
public int ActiveCustomers { get; set; }
public Dictionary<string, int> TopProductsLastHour { get; set; } = new();
public double OrdersPerMinute { get; set; }
}
public class BulkUpdateState
{
public string OperationId { get; set; } = "";
public int ProcessedCount { get; set; }
public int UpdatedCount { get; set; }
public int FailedCount { get; set; }
public DateTime LastCheckpoint { get; set; }
}
public class ReportState
{
public string ReportId { get; set; } = "";
public int ProgressPercent { get; set; }
public Dictionary<string, object> PartialResults { get; set; } = new();
public DateTime LastCheckpoint { get; set; }
}
public class PatternAnalysisResult
{
public Dictionary<string, double> OrderPatterns { get; set; } = new();
public List<CustomerSegment> CustomerSegments { get; set; } = new();
public SeasonalAnalysis? SeasonalAnalysis { get; set; }
public long AnalysisTimeMs { get; set; }
public long RecordsProcessed { get; set; }
public long MemoryUsedMB { get; set; }
}
public class CustomerSegment
{
public string SegmentName { get; set; } = "";
public int CustomerCount { get; set; }
public Dictionary<string, double> Characteristics { get; set; } = new();
}
public class SeasonalAnalysis
{
public Dictionary<string, double> MonthlySalesPattern { get; set; } = new();
public Dictionary<string, double> WeeklySalesPattern { get; set; } = new();
public List<string> PeakPeriods { get; set; } = new();
}
public class MemoryStatistics
{
public long CurrentMemoryUsageMB { get; set; }
public long PeakMemoryUsageMB { get; set; }
public int ExternalSortOperations { get; set; }
public int CheckpointsSaved { get; set; }
public long DataSpilledToDiskMB { get; set; }
public double CacheHitRate { get; set; }
public string CurrentMemoryPressure { get; set; } = "";
}

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using Microsoft.EntityFrameworkCore;
using SqrtSpace.SpaceTime.AspNetCore;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.EntityFramework;
using SqrtSpace.SpaceTime.Linq;
using SampleWebApi.Data;
using SampleWebApi.Services;
var builder = WebApplication.CreateBuilder(args);
// Add services to the container
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new() {
Title = "SqrtSpace SpaceTime Sample API",
Version = "v1",
Description = "Demonstrates memory-efficient data processing using √n space-time tradeoffs"
});
});
// Configure SpaceTime services with memory-aware settings
builder.Services.AddSpaceTime(options =>
{
options.EnableCheckpointing = true;
options.CheckpointDirectory = Path.Combine(Path.GetTempPath(), "spacetime-sample");
options.CheckpointStrategy = CheckpointStrategy.SqrtN;
options.DefaultChunkSize = 1000;
options.StreamingBufferSize = 64 * 1024; // 64KB
options.ExternalStorageDirectory = Path.Combine(Path.GetTempPath(), "spacetime-external");
});
// Add Entity Framework with in-memory database for demo
builder.Services.AddDbContext<SampleDbContext>(options =>
{
options.UseInMemoryDatabase("SampleDb");
// SpaceTime optimizations are available via EF integration
});
// Add application services
builder.Services.AddScoped<IProductService, ProductService>();
builder.Services.AddScoped<IOrderAnalyticsService, OrderAnalyticsService>();
builder.Services.AddHostedService<DataGeneratorService>();
// Configure memory limits
builder.Services.Configure<SampleWebApi.Models.MemoryOptions>(builder.Configuration.GetSection("MemoryOptions"));
var app = builder.Build();
// Configure the HTTP request pipeline
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
// Enable SpaceTime middleware for automatic memory management
app.UseSpaceTime();
app.MapControllers();
// Ensure database is created and seeded
using (var scope = app.Services.CreateScope())
{
var context = scope.ServiceProvider.GetRequiredService<SampleDbContext>();
await DataSeeder.SeedAsync(context);
}
app.Run();

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{
"profiles": {
"SampleWebApi": {
"commandName": "Project",
"launchBrowser": true,
"environmentVariables": {
"ASPNETCORE_ENVIRONMENT": "Development"
},
"applicationUrl": "https://localhost:50878;http://localhost:50881"
}
}
}

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# SqrtSpace SpaceTime Sample Web API
This sample demonstrates how to build a memory-efficient Web API using the SqrtSpace SpaceTime library. It showcases real-world scenarios where √n space-time tradeoffs can significantly improve application performance and scalability.
## Features Demonstrated
### 1. **Memory-Efficient Data Processing**
- Streaming large datasets without loading everything into memory
- Automatic batching using √n-sized chunks
- External sorting and aggregation for datasets that exceed memory limits
### 2. **Checkpoint-Enabled Operations**
- Resumable bulk operations that can recover from failures
- Progress tracking for long-running tasks
- Automatic state persistence at optimal intervals
### 3. **Real-World API Patterns**
#### Products Controller (`/api/products`)
- **Paginated queries** - Basic memory control through pagination
- **Streaming endpoints** - Stream millions of products using NDJSON format
- **Smart search** - Automatically switches to external sorting for large result sets
- **Bulk updates** - Checkpoint-enabled price updates that can resume after failures
- **CSV export** - Stream large exports without memory bloat
- **Statistics** - Calculate aggregates over large datasets efficiently
#### Analytics Controller (`/api/analytics`)
- **Revenue analysis** - External grouping for large-scale aggregations
- **Top customers** - Find top N using external sorting when needed
- **Real-time streaming** - Server-Sent Events for continuous analytics
- **Complex reports** - Multi-stage report generation with checkpointing
- **Pattern analysis** - ML-ready data processing with memory constraints
- **Memory monitoring** - Track how the system manages memory
### 4. **Automatic Memory Management**
- Adapts processing strategy based on data size
- Spills to disk when memory pressure is detected
- Provides memory usage statistics for monitoring
## Running the Sample
1. **Start the API:**
```bash
dotnet run
```
2. **Access Swagger UI:**
Navigate to `https://localhost:5001/swagger` to explore the API
3. **Generate Test Data:**
The application automatically seeds the database with:
- 1,000 customers
- 10,000 products
- 50,000 orders
A background service continuously generates new orders to simulate real-time data.
## Key Scenarios to Try
### 1. Stream Large Dataset
```bash
# Stream all products (10,000+) without loading into memory
curl -N https://localhost:5001/api/products/stream
# The response is newline-delimited JSON (NDJSON)
```
### 2. Bulk Update with Checkpointing
```bash
# Start a bulk price update
curl -X POST https://localhost:5001/api/products/bulk-update-prices \
-H "Content-Type: application/json" \
-H "X-Operation-Id: price-update-123" \
-d '{"categoryFilter": "Electronics", "priceMultiplier": 1.1}'
# If it fails, resume with the same Operation ID
```
### 3. Generate Complex Report
```bash
# Generate a report with automatic checkpointing
curl -X POST https://localhost:5001/api/analytics/reports/generate \
-H "Content-Type: application/json" \
-d '{
"startDate": "2024-01-01",
"endDate": "2024-12-31",
"metricsToInclude": ["revenue", "categories", "customers", "products"],
"includeDetailedBreakdown": true
}'
```
### 4. Real-Time Analytics Stream
```bash
# Connect to real-time analytics stream
curl -N https://localhost:5001/api/analytics/real-time/orders
# Streams analytics data every second using Server-Sent Events
```
### 5. Export Large Dataset
```bash
# Export all products to CSV (streams the file)
curl https://localhost:5001/api/products/export/csv > products.csv
```
## Memory Efficiency Examples
### Small Dataset (In-Memory Processing)
When working with small datasets (<10,000 items), the API uses standard in-memory processing:
```csharp
// Standard LINQ operations
var results = await query
.Where(p => p.Category == "Books")
.OrderBy(p => p.Price)
.ToListAsync();
```
### Large Dataset (External Processing)
For large datasets (>10,000 items), the API automatically switches to external processing:
```csharp
// Automatic external sorting
if (count > 10000)
{
query = query.UseExternalSorting();
}
// Process in √n-sized batches
await foreach (var batch in query.BatchBySqrtNAsync())
{
// Process batch
}
```
## Configuration
The sample includes configurable memory limits:
```csharp
// appsettings.json
{
"MemoryOptions": {
"MaxMemoryMB": 512,
"WarningThresholdPercent": 80
}
}
```
## Monitoring
Check memory usage statistics:
```bash
curl https://localhost:5001/api/analytics/memory-stats
```
Response:
```json
{
"currentMemoryUsageMB": 245,
"peakMemoryUsageMB": 412,
"externalSortOperations": 3,
"checkpointsSaved": 15,
"dataSpilledToDiskMB": 89,
"cacheHitRate": 0.87,
"currentMemoryPressure": "Medium"
}
```
## Architecture Highlights
1. **Service Layer**: Encapsulates business logic and SpaceTime optimizations
2. **Entity Framework Integration**: Seamless integration with EF Core queries
3. **Middleware**: Automatic checkpoint and streaming support
4. **Background Services**: Continuous data generation for testing
5. **Memory Monitoring**: Real-time tracking of memory usage
## Best Practices Demonstrated
1. **Know Your Data Size**: Check count before choosing processing strategy
2. **Stream When Possible**: Use IAsyncEnumerable for large results
3. **Checkpoint Long Operations**: Enable recovery from failures
4. **Monitor Memory Usage**: Track and respond to memory pressure
5. **Use External Processing**: Let the library handle large datasets efficiently
## Next Steps
- Modify the memory limits and observe behavior changes
- Add your own endpoints using SpaceTime patterns
- Connect to a real database for production scenarios
- Implement caching with hot/cold storage tiers
- Add distributed processing with Redis coordination

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<Project Sdk="Microsoft.NET.Sdk.Web">
<PropertyGroup>
<TargetFramework>net9.0</TargetFramework>
<Nullable>enable</Nullable>
<ImplicitUsings>enable</ImplicitUsings>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="9.0.0" />
<PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.AspNetCore\SqrtSpace.SpaceTime.AspNetCore.csproj" />
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.Linq\SqrtSpace.SpaceTime.Linq.csproj" />
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.EntityFramework\SqrtSpace.SpaceTime.EntityFramework.csproj" />
<ProjectReference Include="..\..\src\SqrtSpace.SpaceTime.Caching\SqrtSpace.SpaceTime.Caching.csproj" />
</ItemGroup>
</Project>

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using Microsoft.Extensions.Options;
using SampleWebApi.Data;
using SampleWebApi.Models;
namespace SampleWebApi.Services;
/// <summary>
/// Background service that continuously generates new orders to simulate real-time data
/// </summary>
public class DataGeneratorService : BackgroundService
{
private readonly IServiceProvider _serviceProvider;
private readonly ILogger<DataGeneratorService> _logger;
private readonly Random _random = new();
public DataGeneratorService(IServiceProvider serviceProvider, ILogger<DataGeneratorService> logger)
{
_serviceProvider = serviceProvider;
_logger = logger;
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
_logger.LogInformation("Data generator service started");
while (!stoppingToken.IsCancellationRequested)
{
try
{
await GenerateNewOrdersAsync(stoppingToken);
// Wait between 5-15 seconds before generating next batch
var delay = _random.Next(5000, 15000);
await Task.Delay(delay, stoppingToken);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error generating data");
await Task.Delay(60000, stoppingToken); // Wait 1 minute on error
}
}
}
private async Task GenerateNewOrdersAsync(CancellationToken cancellationToken)
{
using var scope = _serviceProvider.CreateScope();
var context = scope.ServiceProvider.GetRequiredService<SampleDbContext>();
// Generate 1-5 new orders
var orderCount = _random.Next(1, 6);
// Get random customers and products
var customers = context.Customers
.OrderBy(c => Guid.NewGuid())
.Take(orderCount)
.ToList();
if (!customers.Any())
{
_logger.LogWarning("No customers found for data generation");
return;
}
var products = context.Products
.Where(p => p.StockQuantity > 0)
.OrderBy(p => Guid.NewGuid())
.Take(orderCount * 5) // Get more products for variety
.ToList();
if (!products.Any())
{
_logger.LogWarning("No products in stock for data generation");
return;
}
var newOrders = new List<Order>();
foreach (var customer in customers)
{
var itemCount = _random.Next(1, 6);
var orderItems = new List<OrderItem>();
decimal totalAmount = 0;
// Select random products for this order
var orderProducts = products
.OrderBy(p => Guid.NewGuid())
.Take(itemCount)
.ToList();
foreach (var product in orderProducts)
{
var quantity = Math.Min(_random.Next(1, 4), product.StockQuantity);
if (quantity == 0) continue;
var itemTotal = product.Price * quantity;
totalAmount += itemTotal;
orderItems.Add(new OrderItem
{
ProductId = product.Id,
Quantity = quantity,
UnitPrice = product.Price,
TotalPrice = itemTotal
});
// Update stock
product.StockQuantity -= quantity;
}
if (orderItems.Any())
{
newOrders.Add(new Order
{
CustomerId = customer.Id,
OrderDate = DateTime.UtcNow,
TotalAmount = totalAmount,
Status = "Pending",
Items = orderItems
});
}
}
if (newOrders.Any())
{
await context.Orders.AddRangeAsync(newOrders, cancellationToken);
await context.SaveChangesAsync(cancellationToken);
_logger.LogInformation("Generated {count} new orders", newOrders.Count);
}
}
}

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using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.EntityFramework;
using SqrtSpace.SpaceTime.Linq;
using SampleWebApi.Data;
using SampleWebApi.Models;
using System.Diagnostics;
namespace SampleWebApi.Services;
public interface IOrderAnalyticsService
{
Task<IEnumerable<CategoryRevenue>> GetRevenueByCategoryAsync(DateTime? startDate, DateTime? endDate);
Task<IEnumerable<CustomerSummary>> GetTopCustomersAsync(int top, DateTime? since);
IAsyncEnumerable<RealTimeAnalytics> StreamRealTimeAnalyticsAsync(CancellationToken cancellationToken);
Task<ReportResult> GenerateComplexReportAsync(ReportRequest request, string reportId, ReportState? previousState, CheckpointManager? checkpoint);
Task<PatternAnalysisResult> AnalyzeOrderPatternsAsync(PatternAnalysisRequest request);
MemoryStatistics GetMemoryStatistics();
}
public class OrderAnalyticsService : IOrderAnalyticsService
{
private readonly SampleDbContext _context;
private readonly ILogger<OrderAnalyticsService> _logger;
private readonly MemoryOptions _memoryOptions;
private static readonly MemoryStatistics _memoryStats = new();
public OrderAnalyticsService(
SampleDbContext context,
ILogger<OrderAnalyticsService> logger,
IOptions<MemoryOptions> memoryOptions)
{
_context = context;
_logger = logger;
_memoryOptions = memoryOptions.Value;
}
public async Task<IEnumerable<CategoryRevenue>> GetRevenueByCategoryAsync(DateTime? startDate, DateTime? endDate)
{
var query = _context.OrderItems
.Include(oi => oi.Product)
.Include(oi => oi.Order)
.AsQueryable();
if (startDate.HasValue)
query = query.Where(oi => oi.Order.OrderDate >= startDate.Value);
if (endDate.HasValue)
query = query.Where(oi => oi.Order.OrderDate <= endDate.Value);
var itemCount = await query.CountAsync();
_logger.LogInformation("Processing revenue for {count} order items", itemCount);
// Use external grouping for large datasets
if (itemCount > 50000)
{
_logger.LogInformation("Using external grouping for revenue calculation");
_memoryStats.ExternalSortOperations++;
var categoryRevenue = new Dictionary<string, (decimal revenue, int count)>();
// Process in memory-efficient batches
await foreach (var batch in query.BatchBySqrtNAsync())
{
foreach (var item in batch)
{
var category = item.Product.Category;
if (!categoryRevenue.ContainsKey(category))
{
categoryRevenue[category] = (0, 0);
}
var current = categoryRevenue[category];
categoryRevenue[category] = (current.revenue + item.TotalPrice, current.count + 1);
}
}
return categoryRevenue.Select(kvp => new CategoryRevenue
{
Category = kvp.Key,
TotalRevenue = kvp.Value.revenue,
OrderCount = kvp.Value.count,
AverageOrderValue = kvp.Value.count > 0 ? kvp.Value.revenue / kvp.Value.count : 0
}).OrderByDescending(c => c.TotalRevenue);
}
else
{
// Use in-memory grouping for smaller datasets
var grouped = await query
.GroupBy(oi => oi.Product.Category)
.Select(g => new CategoryRevenue
{
Category = g.Key,
TotalRevenue = g.Sum(oi => oi.TotalPrice),
OrderCount = g.Select(oi => oi.OrderId).Distinct().Count(),
AverageOrderValue = g.Average(oi => oi.TotalPrice)
})
.OrderByDescending(c => c.TotalRevenue)
.ToListAsync();
return grouped;
}
}
public async Task<IEnumerable<CustomerSummary>> GetTopCustomersAsync(int top, DateTime? since)
{
var query = _context.Orders.AsQueryable();
if (since.HasValue)
query = query.Where(o => o.OrderDate >= since.Value);
var orderCount = await query.CountAsync();
_logger.LogInformation("Finding top {top} customers from {count} orders", top, orderCount);
// For large datasets, use external sorting
if (orderCount > 100000)
{
_logger.LogInformation("Using external sorting for top customers");
_memoryStats.ExternalSortOperations++;
var customerData = new Dictionary<string, (decimal total, int count, DateTime first, DateTime last)>();
// Aggregate customer data in batches
await foreach (var batch in query.BatchBySqrtNAsync())
{
foreach (var order in batch)
{
if (!customerData.ContainsKey(order.CustomerId))
{
customerData[order.CustomerId] = (0, 0, order.OrderDate, order.OrderDate);
}
var current = customerData[order.CustomerId];
customerData[order.CustomerId] = (
current.total + order.TotalAmount,
current.count + 1,
order.OrderDate < current.first ? order.OrderDate : current.first,
order.OrderDate > current.last ? order.OrderDate : current.last
);
}
}
// Get customer details
var customerIds = customerData.Keys.ToList();
var customers = await _context.Customers
.Where(c => customerIds.Contains(c.Id))
.ToDictionaryAsync(c => c.Id, c => c.Name);
// Sort and take top N
return customerData
.OrderByDescending(kvp => kvp.Value.total)
.Take(top)
.Select(kvp => new CustomerSummary
{
CustomerId = kvp.Key,
CustomerName = customers.GetValueOrDefault(kvp.Key, "Unknown"),
TotalOrders = kvp.Value.count,
TotalSpent = kvp.Value.total,
AverageOrderValue = kvp.Value.total / kvp.Value.count,
FirstOrderDate = kvp.Value.first,
LastOrderDate = kvp.Value.last
});
}
else
{
// Use in-memory processing for smaller datasets
var topCustomers = await query
.GroupBy(o => o.CustomerId)
.Select(g => new
{
CustomerId = g.Key,
TotalSpent = g.Sum(o => o.TotalAmount),
OrderCount = g.Count(),
FirstOrder = g.Min(o => o.OrderDate),
LastOrder = g.Max(o => o.OrderDate)
})
.OrderByDescending(c => c.TotalSpent)
.Take(top)
.ToListAsync();
var customerIds = topCustomers.Select(c => c.CustomerId).ToList();
var customers = await _context.Customers
.Where(c => customerIds.Contains(c.Id))
.ToDictionaryAsync(c => c.Id, c => c.Name);
return topCustomers.Select(c => new CustomerSummary
{
CustomerId = c.CustomerId,
CustomerName = customers.GetValueOrDefault(c.CustomerId, "Unknown"),
TotalOrders = c.OrderCount,
TotalSpent = c.TotalSpent,
AverageOrderValue = c.TotalSpent / c.OrderCount,
FirstOrderDate = c.FirstOrder,
LastOrderDate = c.LastOrder
});
}
}
public async IAsyncEnumerable<RealTimeAnalytics> StreamRealTimeAnalyticsAsync(
[System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
var now = DateTime.UtcNow;
var hourAgo = now.AddHours(-1);
// Get orders from last hour
var recentOrders = await _context.Orders
.Where(o => o.OrderDate >= hourAgo)
.Include(o => o.Items)
.ThenInclude(oi => oi.Product)
.ToListAsync(cancellationToken);
// Calculate analytics
var analytics = new RealTimeAnalytics
{
Timestamp = now,
OrdersLastHour = recentOrders.Count,
RevenueLastHour = recentOrders.Sum(o => o.TotalAmount),
ActiveCustomers = recentOrders.Select(o => o.CustomerId).Distinct().Count(),
OrdersPerMinute = recentOrders.Count / 60.0
};
// Get top products
analytics.TopProductsLastHour = recentOrders
.SelectMany(o => o.Items)
.GroupBy(oi => oi.Product.Name)
.OrderByDescending(g => g.Sum(oi => oi.Quantity))
.Take(5)
.ToDictionary(g => g.Key, g => g.Sum(oi => oi.Quantity));
yield return analytics;
// Update memory stats
var process = Process.GetCurrentProcess();
_memoryStats.CurrentMemoryUsageMB = process.WorkingSet64 / (1024 * 1024);
_memoryStats.PeakMemoryUsageMB = Math.Max(_memoryStats.PeakMemoryUsageMB, _memoryStats.CurrentMemoryUsageMB);
await Task.Delay(1000, cancellationToken); // Wait before next update
}
}
public async Task<ReportResult> GenerateComplexReportAsync(
ReportRequest request,
string reportId,
ReportState? previousState,
CheckpointManager? checkpoint)
{
var stopwatch = Stopwatch.StartNew();
var state = previousState ?? new ReportState { ReportId = reportId };
var result = new ReportResult
{
ReportId = reportId,
GeneratedAt = DateTime.UtcNow,
Metrics = state.PartialResults
};
try
{
// Step 1: Calculate total revenue (0-25%)
if (state.ProgressPercent < 25)
{
var revenue = await CalculateTotalRevenueAsync(request.StartDate, request.EndDate);
result.Metrics["totalRevenue"] = revenue;
state.ProgressPercent = 25;
if (checkpoint?.ShouldCheckpoint() == true)
{
state.PartialResults = result.Metrics;
await checkpoint.CreateCheckpointAsync(state);
_memoryStats.CheckpointsSaved++;
}
}
// Step 2: Calculate category breakdown (25-50%)
if (state.ProgressPercent < 50)
{
var categoryRevenue = await GetRevenueByCategoryAsync(request.StartDate, request.EndDate);
result.Metrics["categoryBreakdown"] = categoryRevenue;
state.ProgressPercent = 50;
if (checkpoint?.ShouldCheckpoint() == true)
{
state.PartialResults = result.Metrics;
await checkpoint.CreateCheckpointAsync(state);
_memoryStats.CheckpointsSaved++;
}
}
// Step 3: Customer analytics (50-75%)
if (state.ProgressPercent < 75)
{
var topCustomers = await GetTopCustomersAsync(100, request.StartDate);
result.Metrics["topCustomers"] = topCustomers;
state.ProgressPercent = 75;
if (checkpoint?.ShouldCheckpoint() == true)
{
state.PartialResults = result.Metrics;
await checkpoint.CreateCheckpointAsync(state);
_memoryStats.CheckpointsSaved++;
}
}
// Step 4: Product performance (75-100%)
if (state.ProgressPercent < 100)
{
var productStats = await CalculateProductPerformanceAsync(request.StartDate, request.EndDate);
result.Metrics["productPerformance"] = productStats;
state.ProgressPercent = 100;
}
result.Completed = true;
result.ProgressPercent = 100;
result.ProcessingTimeMs = stopwatch.ElapsedMilliseconds;
result.MemoryUsedMB = _memoryStats.CurrentMemoryUsageMB;
_logger.LogInformation("Report {reportId} completed in {time}ms", reportId, result.ProcessingTimeMs);
return result;
}
catch (Exception ex)
{
_logger.LogError(ex, "Error generating report {reportId}", reportId);
// Save checkpoint on error
if (checkpoint != null)
{
state.PartialResults = result.Metrics;
await checkpoint.CreateCheckpointAsync(state);
}
throw;
}
}
public async Task<PatternAnalysisResult> AnalyzeOrderPatternsAsync(PatternAnalysisRequest request)
{
var stopwatch = Stopwatch.StartNew();
var result = new PatternAnalysisResult();
// Limit the analysis scope
var orders = await _context.Orders
.OrderByDescending(o => o.OrderDate)
.Take(request.MaxOrdersToAnalyze)
.Include(o => o.Items)
.ToListAsync();
result.RecordsProcessed = orders.Count;
// Analyze order patterns
result.OrderPatterns["averageOrderValue"] = orders.Average(o => (double)o.TotalAmount);
result.OrderPatterns["ordersPerDay"] = orders
.GroupBy(o => o.OrderDate.Date)
.Average(g => g.Count());
// Customer segmentation
if (request.IncludeCustomerSegmentation)
{
var customerGroups = orders
.GroupBy(o => o.CustomerId)
.Select(g => new
{
CustomerId = g.Key,
OrderCount = g.Count(),
TotalSpent = g.Sum(o => o.TotalAmount),
AverageOrder = g.Average(o => o.TotalAmount)
})
.ToList();
// Simple segmentation based on spending
result.CustomerSegments = new List<CustomerSegment>
{
new CustomerSegment
{
SegmentName = "High Value",
CustomerCount = customerGroups.Count(c => c.TotalSpent > 1000),
Characteristics = new Dictionary<string, double>
{
["averageOrderValue"] = customerGroups.Where(c => c.TotalSpent > 1000).Average(c => (double)c.AverageOrder),
["ordersPerCustomer"] = customerGroups.Where(c => c.TotalSpent > 1000).Average(c => c.OrderCount)
}
},
new CustomerSegment
{
SegmentName = "Regular",
CustomerCount = customerGroups.Count(c => c.TotalSpent >= 100 && c.TotalSpent <= 1000),
Characteristics = new Dictionary<string, double>
{
["averageOrderValue"] = customerGroups.Where(c => c.TotalSpent >= 100 && c.TotalSpent <= 1000).Average(c => (double)c.AverageOrder),
["ordersPerCustomer"] = customerGroups.Where(c => c.TotalSpent >= 100 && c.TotalSpent <= 1000).Average(c => c.OrderCount)
}
}
};
}
// Seasonal analysis
if (request.IncludeSeasonalAnalysis)
{
result.SeasonalAnalysis = new SeasonalAnalysis
{
MonthlySalesPattern = orders
.GroupBy(o => o.OrderDate.Month)
.ToDictionary(g => g.Key.ToString(), g => (double)g.Sum(o => o.TotalAmount)),
WeeklySalesPattern = orders
.GroupBy(o => o.OrderDate.DayOfWeek)
.ToDictionary(g => g.Key.ToString(), g => (double)g.Sum(o => o.TotalAmount)),
PeakPeriods = orders
.GroupBy(o => o.OrderDate.Date)
.OrderByDescending(g => g.Sum(o => o.TotalAmount))
.Take(5)
.Select(g => g.Key.ToString("yyyy-MM-dd"))
.ToList()
};
}
result.AnalysisTimeMs = stopwatch.ElapsedMilliseconds;
result.MemoryUsedMB = _memoryStats.CurrentMemoryUsageMB;
return result;
}
public MemoryStatistics GetMemoryStatistics()
{
var process = Process.GetCurrentProcess();
_memoryStats.CurrentMemoryUsageMB = process.WorkingSet64 / (1024 * 1024);
// Determine memory pressure
var usagePercent = (_memoryStats.CurrentMemoryUsageMB * 100) / _memoryOptions.MaxMemoryMB;
_memoryStats.CurrentMemoryPressure = usagePercent switch
{
< 50 => "Low",
< 80 => "Medium",
_ => "High"
};
return _memoryStats;
}
private async Task<decimal> CalculateTotalRevenueAsync(DateTime startDate, DateTime endDate)
{
var revenue = await _context.Orders
.Where(o => o.OrderDate >= startDate && o.OrderDate <= endDate)
.SumAsync(o => o.TotalAmount);
return revenue;
}
private async Task<object> CalculateProductPerformanceAsync(DateTime startDate, DateTime endDate)
{
var query = _context.OrderItems
.Include(oi => oi.Product)
.Include(oi => oi.Order)
.Where(oi => oi.Order.OrderDate >= startDate && oi.Order.OrderDate <= endDate);
var productPerformance = await query
.GroupBy(oi => new { oi.ProductId, oi.Product.Name })
.Select(g => new
{
ProductId = g.Key.ProductId,
ProductName = g.Key.Name,
UnitsSold = g.Sum(oi => oi.Quantity),
Revenue = g.Sum(oi => oi.TotalPrice),
OrderCount = g.Select(oi => oi.OrderId).Distinct().Count()
})
.OrderByDescending(p => p.Revenue)
.Take(50)
.ToListAsync();
return productPerformance;
}
}

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using Microsoft.EntityFrameworkCore;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.EntityFramework;
using SqrtSpace.SpaceTime.Linq;
using SampleWebApi.Data;
using SampleWebApi.Models;
using System.Text;
namespace SampleWebApi.Services;
public interface IProductService
{
Task<PagedResult<Product>> GetProductsPagedAsync(int page, int pageSize);
IAsyncEnumerable<Product> StreamProductsAsync(string? category, decimal? minPrice);
Task<IEnumerable<Product>> SearchProductsAsync(string query, string sortBy, bool descending);
Task<BulkUpdateResult> BulkUpdatePricesAsync(string? categoryFilter, decimal priceMultiplier, string operationId, CheckpointManager? checkpoint);
Task ExportToCsvAsync(Stream outputStream, string? category);
Task<ProductStatistics> GetStatisticsAsync(string? category);
}
public class ProductService : IProductService
{
private readonly SampleDbContext _context;
private readonly ILogger<ProductService> _logger;
public ProductService(SampleDbContext context, ILogger<ProductService> logger)
{
_context = context;
_logger = logger;
}
public async Task<PagedResult<Product>> GetProductsPagedAsync(int page, int pageSize)
{
var query = _context.Products.AsQueryable();
var totalCount = await query.CountAsync();
var items = await query
.Skip((page - 1) * pageSize)
.Take(pageSize)
.ToListAsync();
return new PagedResult<Product>
{
Items = items,
Page = page,
PageSize = pageSize,
TotalCount = totalCount
};
}
public async IAsyncEnumerable<Product> StreamProductsAsync(string? category, decimal? minPrice)
{
var query = _context.Products.AsQueryable();
if (!string.IsNullOrEmpty(category))
{
query = query.Where(p => p.Category == category);
}
if (minPrice.HasValue)
{
query = query.Where(p => p.Price >= minPrice.Value);
}
// Use BatchBySqrtN to process in memory-efficient chunks
await foreach (var batch in query.BatchBySqrtNAsync())
{
foreach (var product in batch)
{
yield return product;
}
}
}
public async Task<IEnumerable<Product>> SearchProductsAsync(string query, string sortBy, bool descending)
{
var searchQuery = _context.Products
.Where(p => p.Name.Contains(query) || p.Description.Contains(query));
// Count to determine if we need external sorting
var count = await searchQuery.CountAsync();
_logger.LogInformation("Search found {count} products for query '{query}'", count, query);
IQueryable<Product> sortedQuery = sortBy.ToLower() switch
{
"price" => descending ? searchQuery.OrderByDescending(p => p.Price) : searchQuery.OrderBy(p => p.Price),
"category" => descending ? searchQuery.OrderByDescending(p => p.Category) : searchQuery.OrderBy(p => p.Category),
_ => descending ? searchQuery.OrderByDescending(p => p.Name) : searchQuery.OrderBy(p => p.Name)
};
// Use external sorting for large result sets
if (count > 10000)
{
_logger.LogInformation("Using external sorting for {count} products", count);
sortedQuery = sortedQuery.UseExternalSorting();
}
return await sortedQuery.ToListAsync();
}
public async Task<BulkUpdateResult> BulkUpdatePricesAsync(
string? categoryFilter,
decimal priceMultiplier,
string operationId,
CheckpointManager? checkpoint)
{
var state = new BulkUpdateState { OperationId = operationId };
// Try to restore from checkpoint
if (checkpoint != null)
{
var previousState = await checkpoint.RestoreLatestCheckpointAsync<BulkUpdateState>();
if (previousState != null)
{
state = previousState;
_logger.LogInformation("Resuming bulk update from checkpoint. Already processed: {count}",
state.ProcessedCount);
}
}
var query = _context.Products.AsQueryable();
if (!string.IsNullOrEmpty(categoryFilter))
{
query = query.Where(p => p.Category == categoryFilter);
}
var totalProducts = await query.CountAsync();
var products = query.Skip(state.ProcessedCount);
// Process in batches using √n strategy
await foreach (var batch in products.BatchBySqrtNAsync())
{
try
{
foreach (var product in batch)
{
product.Price *= priceMultiplier;
product.UpdatedAt = DateTime.UtcNow;
state.ProcessedCount++;
state.UpdatedCount++;
}
await _context.SaveChangesAsync();
// Save checkpoint
if (checkpoint?.ShouldCheckpoint() == true)
{
state.LastCheckpoint = DateTime.UtcNow;
await checkpoint.CreateCheckpointAsync(state);
_logger.LogInformation("Checkpoint saved. Processed: {count}/{total}",
state.ProcessedCount, totalProducts);
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error updating batch. Processed so far: {count}", state.ProcessedCount);
state.FailedCount += batch.Count - (state.ProcessedCount % batch.Count);
// Save checkpoint on error
if (checkpoint != null)
{
await checkpoint.CreateCheckpointAsync(state);
}
throw;
}
}
return new BulkUpdateResult
{
OperationId = operationId,
TotalProducts = totalProducts,
UpdatedProducts = state.UpdatedCount,
FailedProducts = state.FailedCount,
Completed = true,
CheckpointId = state.LastCheckpoint.ToString("O")
};
}
public async Task ExportToCsvAsync(Stream outputStream, string? category)
{
using var writer = new StreamWriter(outputStream, Encoding.UTF8);
// Write header
await writer.WriteLineAsync("Id,Name,Category,Price,StockQuantity,CreatedAt,UpdatedAt");
var query = _context.Products.AsQueryable();
if (!string.IsNullOrEmpty(category))
{
query = query.Where(p => p.Category == category);
}
// Stream products in batches to minimize memory usage
await foreach (var batch in query.BatchBySqrtNAsync())
{
foreach (var product in batch)
{
await writer.WriteLineAsync(
$"{product.Id}," +
$"\"{product.Name.Replace("\"", "\"\"")}\"," +
$"\"{product.Category}\"," +
$"{product.Price}," +
$"{product.StockQuantity}," +
$"{product.CreatedAt:yyyy-MM-dd HH:mm:ss}," +
$"{product.UpdatedAt:yyyy-MM-dd HH:mm:ss}");
}
await writer.FlushAsync();
}
}
public async Task<ProductStatistics> GetStatisticsAsync(string? category)
{
var stopwatch = System.Diagnostics.Stopwatch.StartNew();
var query = _context.Products.AsQueryable();
if (!string.IsNullOrEmpty(category))
{
query = query.Where(p => p.Category == category);
}
var totalCount = await query.CountAsync();
var computationMethod = totalCount > 100000 ? "External" : "InMemory";
ProductStatistics stats;
if (computationMethod == "External")
{
_logger.LogInformation("Using external aggregation for {count} products", totalCount);
// For large datasets, compute statistics in batches
decimal totalPrice = 0;
decimal minPrice = decimal.MaxValue;
decimal maxPrice = decimal.MinValue;
var categoryStats = new Dictionary<string, (int count, decimal totalPrice)>();
await foreach (var batch in query.BatchBySqrtNAsync())
{
foreach (var product in batch)
{
totalPrice += product.Price;
minPrice = Math.Min(minPrice, product.Price);
maxPrice = Math.Max(maxPrice, product.Price);
if (!categoryStats.ContainsKey(product.Category))
{
categoryStats[product.Category] = (0, 0);
}
var current = categoryStats[product.Category];
categoryStats[product.Category] = (current.count + 1, current.totalPrice + product.Price);
}
}
stats = new ProductStatistics
{
TotalProducts = totalCount,
AveragePrice = totalCount > 0 ? totalPrice / totalCount : 0,
MinPrice = minPrice == decimal.MaxValue ? 0 : minPrice,
MaxPrice = maxPrice == decimal.MinValue ? 0 : maxPrice,
ProductsByCategory = categoryStats.ToDictionary(k => k.Key, v => v.Value.count),
AveragePriceByCategory = categoryStats.ToDictionary(
k => k.Key,
v => v.Value.count > 0 ? v.Value.totalPrice / v.Value.count : 0)
};
}
else
{
// For smaller datasets, use in-memory aggregation
var products = await query.ToListAsync();
stats = new ProductStatistics
{
TotalProducts = products.Count,
AveragePrice = products.Any() ? products.Average(p => p.Price) : 0,
MinPrice = products.Any() ? products.Min(p => p.Price) : 0,
MaxPrice = products.Any() ? products.Max(p => p.Price) : 0,
ProductsByCategory = products.GroupBy(p => p.Category)
.ToDictionary(g => g.Key, g => g.Count()),
AveragePriceByCategory = products.GroupBy(p => p.Category)
.ToDictionary(g => g.Key, g => g.Average(p => p.Price))
};
}
stats.ComputationTimeMs = stopwatch.ElapsedMilliseconds;
stats.ComputationMethod = computationMethod;
return stats;
}
}

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using System.Collections.Immutable;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
namespace SqrtSpace.SpaceTime.Analyzers;
/// <summary>
/// Analyzer that detects large memory allocations that could benefit from SpaceTime optimizations
/// </summary>
[DiagnosticAnalyzer(LanguageNames.CSharp)]
public class LargeAllocationAnalyzer : DiagnosticAnalyzer
{
public const string DiagnosticId = "ST001";
private const string Category = "Performance";
private static readonly LocalizableString Title = "Large memory allocation detected";
private static readonly LocalizableString MessageFormat = "Consider using SpaceTime optimization for this large {0} operation";
private static readonly LocalizableString Description = "Large memory allocations can be optimized using √n space-time tradeoffs.";
private static readonly DiagnosticDescriptor Rule = new(
DiagnosticId,
Title,
MessageFormat,
Category,
DiagnosticSeverity.Warning,
isEnabledByDefault: true,
description: Description);
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(Rule);
public override void Initialize(AnalysisContext context)
{
context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
context.EnableConcurrentExecution();
context.RegisterSyntaxNodeAction(AnalyzeInvocation, SyntaxKind.InvocationExpression);
context.RegisterSyntaxNodeAction(AnalyzeObjectCreation, SyntaxKind.ObjectCreationExpression);
}
private static void AnalyzeInvocation(SyntaxNodeAnalysisContext context)
{
var invocation = (InvocationExpressionSyntax)context.Node;
var symbol = context.SemanticModel.GetSymbolInfo(invocation).Symbol as IMethodSymbol;
if (symbol == null)
return;
// Check for ToList, ToArray on large collections
if ((symbol.Name == "ToList" || symbol.Name == "ToArray") &&
symbol.ContainingType.Name == "Enumerable")
{
if (IsLargeCollection(invocation, context))
{
var diagnostic = Diagnostic.Create(Rule, invocation.GetLocation(), "collection");
context.ReportDiagnostic(diagnostic);
}
}
// Check for OrderBy, GroupBy on large collections
if ((symbol.Name == "OrderBy" || symbol.Name == "OrderByDescending" ||
symbol.Name == "GroupBy") &&
symbol.ContainingType.Name == "Enumerable")
{
if (IsLargeCollection(invocation, context))
{
var diagnostic = Diagnostic.Create(Rule, invocation.GetLocation(), symbol.Name);
context.ReportDiagnostic(diagnostic);
}
}
}
private static void AnalyzeObjectCreation(SyntaxNodeAnalysisContext context)
{
var objectCreation = (ObjectCreationExpressionSyntax)context.Node;
var symbol = context.SemanticModel.GetSymbolInfo(objectCreation).Symbol as IMethodSymbol;
if (symbol == null)
return;
var type = symbol.ContainingType;
// Check for large array allocations
if (type.SpecialType == SpecialType.System_Array ||
type.TypeKind == TypeKind.Array)
{
if (objectCreation.ArgumentList?.Arguments.Count > 0)
{
var sizeArg = objectCreation.ArgumentList.Arguments[0];
if (IsLargeSize(sizeArg, context))
{
var diagnostic = Diagnostic.Create(Rule, objectCreation.GetLocation(), "array allocation");
context.ReportDiagnostic(diagnostic);
}
}
}
// Check for large List<T> allocations
if (type.Name == "List" && type.ContainingNamespace.ToString() == "System.Collections.Generic")
{
if (objectCreation.ArgumentList?.Arguments.Count > 0)
{
var capacityArg = objectCreation.ArgumentList.Arguments[0];
if (IsLargeSize(capacityArg, context))
{
var diagnostic = Diagnostic.Create(Rule, objectCreation.GetLocation(), "list allocation");
context.ReportDiagnostic(diagnostic);
}
}
}
}
private static bool IsLargeCollection(InvocationExpressionSyntax invocation, SyntaxNodeAnalysisContext context)
{
// Check if the source is a known large collection
if (invocation.Expression is MemberAccessExpressionSyntax memberAccess)
{
var sourceType = context.SemanticModel.GetTypeInfo(memberAccess.Expression).Type;
// Check for database context (Entity Framework)
if (sourceType != null && sourceType.Name.EndsWith("Context"))
{
return true;
}
// Check for collection size hints
var sourceSymbol = context.SemanticModel.GetSymbolInfo(memberAccess.Expression).Symbol;
if (sourceSymbol is IPropertySymbol property && property.Name == "LargeCollection")
{
return true;
}
}
return false;
}
private static bool IsLargeSize(ArgumentSyntax argument, SyntaxNodeAnalysisContext context)
{
var constantValue = context.SemanticModel.GetConstantValue(argument.Expression);
if (constantValue.HasValue && constantValue.Value is int size)
{
return size > 10000; // Consider > 10K as large
}
// If not a constant, assume it could be large
return true;
}
}

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using System.Collections.Immutable;
using System.Composition;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Rename;
namespace SqrtSpace.SpaceTime.Analyzers;
/// <summary>
/// Code fix provider for large allocation analyzer
/// </summary>
[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(LargeAllocationCodeFixProvider)), Shared]
public class LargeAllocationCodeFixProvider : CodeFixProvider
{
public sealed override ImmutableArray<string> FixableDiagnosticIds => ImmutableArray.Create(LargeAllocationAnalyzer.DiagnosticId);
public sealed override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
if (root == null) return;
var diagnostic = context.Diagnostics.First();
var diagnosticSpan = diagnostic.Location.SourceSpan;
// Find the invocation expression
var invocation = root.FindToken(diagnosticSpan.Start).Parent?.AncestorsAndSelf().OfType<InvocationExpressionSyntax>().First();
if (invocation != null)
{
await RegisterInvocationFixesAsync(context, invocation);
}
// Find object creation expression
var objectCreation = root.FindToken(diagnosticSpan.Start).Parent?.AncestorsAndSelf().OfType<ObjectCreationExpressionSyntax>().First();
if (objectCreation != null)
{
await RegisterObjectCreationFixesAsync(context, objectCreation);
}
}
private async Task RegisterInvocationFixesAsync(CodeFixContext context, InvocationExpressionSyntax invocation)
{
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken).ConfigureAwait(false);
if (semanticModel == null) return;
var symbol = semanticModel.GetSymbolInfo(invocation).Symbol as IMethodSymbol;
if (symbol == null) return;
switch (symbol.Name)
{
case "ToList":
context.RegisterCodeFix(
CodeAction.Create(
title: "Use ToCheckpointedListAsync for fault tolerance",
createChangedDocument: c => ReplaceWithCheckpointedListAsync(context.Document, invocation, c),
equivalenceKey: "UseCheckpointedList"),
context.Diagnostics);
break;
case "OrderBy":
case "OrderByDescending":
context.RegisterCodeFix(
CodeAction.Create(
title: "Use OrderByExternal for √n memory usage",
createChangedDocument: c => ReplaceWithExternalOrderBy(context.Document, invocation, symbol.Name, c),
equivalenceKey: "UseExternalOrderBy"),
context.Diagnostics);
break;
case "GroupBy":
context.RegisterCodeFix(
CodeAction.Create(
title: "Use GroupByExternal for √n memory usage",
createChangedDocument: c => ReplaceWithExternalGroupBy(context.Document, invocation, c),
equivalenceKey: "UseExternalGroupBy"),
context.Diagnostics);
break;
}
}
private async Task RegisterObjectCreationFixesAsync(CodeFixContext context, ObjectCreationExpressionSyntax objectCreation)
{
context.RegisterCodeFix(
CodeAction.Create(
title: "Use AdaptiveList for automatic memory optimization",
createChangedDocument: c => ReplaceWithAdaptiveCollection(context.Document, objectCreation, c),
equivalenceKey: "UseAdaptiveCollection"),
context.Diagnostics);
}
private async Task<Document> ReplaceWithCheckpointedListAsync(Document document, InvocationExpressionSyntax invocation, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
if (root == null) return document;
// Create new method name
var newInvocation = invocation.WithExpression(
SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
((MemberAccessExpressionSyntax)invocation.Expression).Expression,
SyntaxFactory.IdentifierName("ToCheckpointedListAsync")));
// Make the containing method async if needed
var containingMethod = invocation.Ancestors().OfType<MethodDeclarationSyntax>().FirstOrDefault();
if (containingMethod != null && !containingMethod.Modifiers.Any(SyntaxKind.AsyncKeyword))
{
var newMethod = containingMethod.AddModifiers(SyntaxFactory.Token(SyntaxKind.AsyncKeyword));
// Change return type to Task<T>
if (containingMethod.ReturnType is not GenericNameSyntax genericReturn || genericReturn.Identifier.Text != "Task")
{
var taskType = SyntaxFactory.GenericName("Task")
.WithTypeArgumentList(SyntaxFactory.TypeArgumentList(
SyntaxFactory.SingletonSeparatedList(containingMethod.ReturnType)));
newMethod = newMethod.WithReturnType(taskType);
}
root = root.ReplaceNode(containingMethod, newMethod);
}
// Add await
var awaitExpression = SyntaxFactory.AwaitExpression(newInvocation);
var newRoot = root.ReplaceNode(invocation, awaitExpression);
// Add using statement
var compilation = await document.Project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
if (compilation != null)
{
var usingDirective = SyntaxFactory.UsingDirective(SyntaxFactory.ParseName("Ubiquity.SpaceTime.Linq"));
if (newRoot is CompilationUnitSyntax compilationUnit)
{
newRoot = compilationUnit.AddUsings(usingDirective);
}
}
return document.WithSyntaxRoot(newRoot);
}
private async Task<Document> ReplaceWithExternalOrderBy(Document document, InvocationExpressionSyntax invocation, string methodName, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
if (root == null) return document;
var newMethodName = methodName == "OrderBy" ? "OrderByExternal" : "OrderByDescendingExternal";
var memberAccess = (MemberAccessExpressionSyntax)invocation.Expression;
var newInvocation = invocation.WithExpression(
memberAccess.WithName(SyntaxFactory.IdentifierName(newMethodName)));
var newRoot = root.ReplaceNode(invocation, newInvocation);
// Add using statement
var usingDirective = SyntaxFactory.UsingDirective(SyntaxFactory.ParseName("Ubiquity.SpaceTime.Linq"));
if (newRoot is CompilationUnitSyntax compilationUnit && !compilationUnit.Usings.Any(u => u.Name?.ToString() == "Ubiquity.SpaceTime.Linq"))
{
newRoot = compilationUnit.AddUsings(usingDirective);
}
return document.WithSyntaxRoot(newRoot);
}
private async Task<Document> ReplaceWithExternalGroupBy(Document document, InvocationExpressionSyntax invocation, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
if (root == null) return document;
var memberAccess = (MemberAccessExpressionSyntax)invocation.Expression;
var newInvocation = invocation.WithExpression(
memberAccess.WithName(SyntaxFactory.IdentifierName("GroupByExternal")));
var newRoot = root.ReplaceNode(invocation, newInvocation);
// Add using statement
var usingDirective = SyntaxFactory.UsingDirective(SyntaxFactory.ParseName("Ubiquity.SpaceTime.Linq"));
if (newRoot is CompilationUnitSyntax compilationUnit && !compilationUnit.Usings.Any(u => u.Name?.ToString() == "Ubiquity.SpaceTime.Linq"))
{
newRoot = compilationUnit.AddUsings(usingDirective);
}
return document.WithSyntaxRoot(newRoot);
}
private async Task<Document> ReplaceWithAdaptiveCollection(Document document, ObjectCreationExpressionSyntax objectCreation, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
if (root == null) return document;
var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
if (semanticModel == null) return document;
var type = semanticModel.GetTypeInfo(objectCreation).Type;
if (type == null) return document;
ExpressionSyntax newExpression;
if (type.Name == "List" && type is INamedTypeSymbol namedType && namedType.TypeArguments.Length == 1)
{
var typeArg = namedType.TypeArguments[0];
var adaptiveType = SyntaxFactory.GenericName("AdaptiveList")
.WithTypeArgumentList(SyntaxFactory.TypeArgumentList(
SyntaxFactory.SingletonSeparatedList(
SyntaxFactory.ParseTypeName(typeArg.ToDisplayString()))));
newExpression = SyntaxFactory.ObjectCreationExpression(adaptiveType)
.WithArgumentList(objectCreation.ArgumentList ?? SyntaxFactory.ArgumentList());
}
else
{
return document; // Can't fix this type
}
var newRoot = root.ReplaceNode(objectCreation, newExpression);
// Add using statement
var usingDirective = SyntaxFactory.UsingDirective(SyntaxFactory.ParseName("Ubiquity.SpaceTime.Collections"));
if (newRoot is CompilationUnitSyntax compilationUnit && !compilationUnit.Usings.Any(u => u.Name?.ToString() == "Ubiquity.SpaceTime.Collections"))
{
newRoot = compilationUnit.AddUsings(usingDirective);
}
return document.WithSyntaxRoot(newRoot);
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard2.0</TargetFramework>
<Description>Roslyn analyzers for detecting and fixing space-time optimization opportunities</Description>
<PackageId>SqrtSpace.SpaceTime.Analyzers</PackageId>
<IsPackable>true</IsPackable>
<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
<!-- Standard analyzer packaging approach -->
<IncludeBuildOutput>true</IncludeBuildOutput>
<DevelopmentDependency>true</DevelopmentDependency>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="4.14.0">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>
<PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.14.0" />
<PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.14.0" />
</ItemGroup>
</Project>

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<?xml version="1.0" encoding="utf-8"?>
<Project>
<ItemGroup>
<Analyzer Include="$(MSBuildThisFileDirectory)..\analyzers\dotnet\cs\SqrtSpace.SpaceTime.Analyzers.dll" />
</ItemGroup>
</Project>

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using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.AspNetCore;
/// <summary>
/// Middleware that enables checkpointing for long-running requests
/// </summary>
public class CheckpointMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<CheckpointMiddleware> _logger;
private readonly CheckpointOptions _options;
public CheckpointMiddleware(
RequestDelegate next,
ILogger<CheckpointMiddleware> logger,
CheckpointOptions options)
{
_next = next;
_logger = logger;
_options = options;
}
public async Task InvokeAsync(HttpContext context)
{
if (!ShouldCheckpoint(context))
{
await _next(context);
return;
}
var checkpointId = context.Request.Headers["X-Checkpoint-Id"].FirstOrDefault();
var checkpointManager = new CheckpointManager(
_options.CheckpointDirectory,
_options.Strategy,
_options.EstimatedOperations);
// Store in HttpContext for access by controllers
context.Features.Set<ICheckpointFeature>(new CheckpointFeature(checkpointManager, checkpointId, _options));
try
{
// If resuming from checkpoint, restore state
if (!string.IsNullOrEmpty(checkpointId))
{
_logger.LogInformation("Resuming from checkpoint {CheckpointId}", checkpointId);
var state = await checkpointManager.RestoreLatestCheckpointAsync<Dictionary<string, object>>();
if (state != null)
{
context.Items["CheckpointState"] = state;
}
}
await _next(context);
}
finally
{
checkpointManager.Dispose();
}
}
private bool ShouldCheckpoint(HttpContext context)
{
// Check if the path matches checkpoint patterns
foreach (var pattern in _options.PathPatterns)
{
if (context.Request.Path.StartsWithSegments(pattern))
{
return true;
}
}
// Check if endpoint has checkpoint attribute
var endpoint = context.GetEndpoint();
if (endpoint != null)
{
var checkpointAttribute = endpoint.Metadata.GetMetadata<EnableCheckpointAttribute>();
return checkpointAttribute != null;
}
return false;
}
}
/// <summary>
/// Options for checkpoint middleware
/// </summary>
public class CheckpointOptions
{
/// <summary>
/// Directory to store checkpoints
/// </summary>
public string? CheckpointDirectory { get; set; }
/// <summary>
/// Checkpointing strategy
/// </summary>
public CheckpointStrategy Strategy { get; set; } = CheckpointStrategy.SqrtN;
/// <summary>
/// Estimated number of operations for √n calculation
/// </summary>
public long EstimatedOperations { get; set; } = 100_000;
/// <summary>
/// Path patterns that should enable checkpointing
/// </summary>
public List<string> PathPatterns { get; set; } = new()
{
"/api/import",
"/api/export",
"/api/process"
};
}
/// <summary>
/// Feature interface for checkpoint access
/// </summary>
public interface ICheckpointFeature
{
CheckpointManager CheckpointManager { get; }
string? CheckpointId { get; }
Task<T?> LoadStateAsync<T>(string key, CancellationToken cancellationToken = default) where T : class;
Task SaveStateAsync<T>(string key, T state, CancellationToken cancellationToken = default) where T : class;
bool ShouldCheckpoint(long currentOperation);
}
/// <summary>
/// Implementation of checkpoint feature
/// </summary>
internal class CheckpointFeature : ICheckpointFeature
{
private readonly CheckpointOptions _options;
private long _operationCount = 0;
public CheckpointFeature(CheckpointManager checkpointManager, string? checkpointId, CheckpointOptions options)
{
CheckpointManager = checkpointManager;
CheckpointId = checkpointId;
_options = options;
}
public CheckpointManager CheckpointManager { get; }
public string? CheckpointId { get; }
public async Task<T?> LoadStateAsync<T>(string key, CancellationToken cancellationToken = default) where T : class
{
if (string.IsNullOrEmpty(CheckpointId))
return null;
return await CheckpointManager.LoadStateAsync<T>(CheckpointId, key, cancellationToken);
}
public async Task SaveStateAsync<T>(string key, T state, CancellationToken cancellationToken = default) where T : class
{
if (string.IsNullOrEmpty(CheckpointId))
return;
await CheckpointManager.SaveStateAsync(CheckpointId, key, state, cancellationToken);
}
public bool ShouldCheckpoint(long currentOperation)
{
_operationCount = currentOperation;
return _options.Strategy switch
{
CheckpointStrategy.SqrtN => currentOperation > 0 && currentOperation % (int)Math.Sqrt(_options.EstimatedOperations) == 0,
CheckpointStrategy.Linear => currentOperation > 0 && currentOperation % 1000 == 0,
CheckpointStrategy.Logarithmic => IsPowerOfTwo(currentOperation),
CheckpointStrategy.None => false,
_ => false
};
}
private static bool IsPowerOfTwo(long n)
{
return n > 0 && (n & (n - 1)) == 0;
}
}
/// <summary>
/// Attribute to enable checkpointing on specific endpoints
/// </summary>
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class)]
public class EnableCheckpointAttribute : Attribute
{
/// <summary>
/// Checkpoint strategy to use
/// </summary>
public CheckpointStrategy Strategy { get; set; } = CheckpointStrategy.SqrtN;
/// <summary>
/// Whether to automatically restore from checkpoint
/// </summary>
public bool AutoRestore { get; set; } = true;
}

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using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.Diagnostics;
namespace SqrtSpace.SpaceTime.AspNetCore;
/// <summary>
/// Extension methods for configuring SpaceTime services
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Adds SpaceTime services to the service collection
/// </summary>
public static IServiceCollection AddSpaceTime(
this IServiceCollection services,
Action<SpaceTimeServiceOptions>? configureOptions = null)
{
var options = new SpaceTimeServiceOptions();
configureOptions?.Invoke(options);
// Register options
services.AddSingleton(options);
// Add checkpoint services if enabled
if (options.EnableCheckpointing)
{
services.AddSingleton(options.CheckpointOptions);
}
// Add streaming services if enabled
if (options.EnableStreaming)
{
services.AddSingleton(options.StreamingOptions);
}
return services;
}
/// <summary>
/// Adds SpaceTime middleware to the pipeline
/// </summary>
public static IApplicationBuilder UseSpaceTime(this IApplicationBuilder app)
{
var options = app.ApplicationServices.GetService<SpaceTimeServiceOptions>();
if (options == null)
{
throw new InvalidOperationException("SpaceTime services not registered. Call AddSpaceTime() in ConfigureServices.");
}
if (options.EnableCheckpointing)
{
var checkpointOptions = app.ApplicationServices.GetRequiredService<CheckpointOptions>();
app.UseMiddleware<CheckpointMiddleware>(checkpointOptions);
}
if (options.EnableStreaming)
{
var streamingOptions = app.ApplicationServices.GetRequiredService<ResponseStreamingOptions>();
app.UseMiddleware<ResponseStreamingMiddleware>(streamingOptions);
}
return app;
}
/// <summary>
/// Maps SpaceTime diagnostic and monitoring endpoints
/// </summary>
public static IApplicationBuilder UseSpaceTimeEndpoints(this IApplicationBuilder app)
{
app.UseEndpoints(endpoints =>
{
// Health check endpoint
endpoints.MapGet("/spacetime/health", async context =>
{
context.Response.StatusCode = 200;
await context.Response.WriteAsync("OK");
});
// Metrics endpoint (for Prometheus scraping)
endpoints.MapGet("/spacetime/metrics", async context =>
{
context.Response.ContentType = "text/plain";
await context.Response.WriteAsync("# SpaceTime metrics endpoint\n");
await context.Response.WriteAsync("# Configure OpenTelemetry with Prometheus exporter for metrics\n");
});
// Diagnostics report endpoint
endpoints.MapGet("/spacetime/diagnostics", async context =>
{
var diagnostics = context.RequestServices.GetService<ISpaceTimeDiagnostics>();
if (diagnostics != null)
{
var report = await diagnostics.GenerateReportAsync(TimeSpan.FromHours(1));
context.Response.ContentType = "application/json";
await context.Response.WriteAsJsonAsync(report);
}
else
{
context.Response.StatusCode = 404;
await context.Response.WriteAsync("Diagnostics not configured");
}
});
// Configuration endpoint
endpoints.MapGet("/spacetime/config", async context =>
{
var options = context.RequestServices.GetService<SpaceTimeServiceOptions>();
if (options != null)
{
context.Response.ContentType = "application/json";
await context.Response.WriteAsJsonAsync(options);
}
else
{
context.Response.StatusCode = 404;
await context.Response.WriteAsync("Configuration not found");
}
});
});
return app;
}
}
/// <summary>
/// Options for SpaceTime services
/// </summary>
public class SpaceTimeServiceOptions
{
/// <summary>
/// Enable checkpointing middleware
/// </summary>
public bool EnableCheckpointing { get; set; } = true;
/// <summary>
/// Enable streaming optimizations
/// </summary>
public bool EnableStreaming { get; set; } = true;
/// <summary>
/// Options for checkpointing
/// </summary>
public CheckpointOptions CheckpointOptions { get; set; } = new();
/// <summary>
/// Options for streaming
/// </summary>
public ResponseStreamingOptions StreamingOptions { get; set; } = new();
/// <summary>
/// Directory for storing checkpoints
/// </summary>
public string CheckpointDirectory { get; set; } = Path.Combine(Path.GetTempPath(), "spacetime-checkpoints");
/// <summary>
/// Checkpointing strategy to use
/// </summary>
public CheckpointStrategy CheckpointStrategy { get; set; } = CheckpointStrategy.SqrtN;
/// <summary>
/// Interval for checkpointing operations
/// </summary>
public TimeSpan CheckpointInterval { get; set; } = TimeSpan.FromSeconds(30);
/// <summary>
/// Directory for external storage operations
/// </summary>
public string ExternalStorageDirectory { get; set; } = Path.Combine(Path.GetTempPath(), "spacetime-storage");
/// <summary>
/// Default strategy for space-time operations
/// </summary>
public SpaceTimeStrategy DefaultStrategy { get; set; } = SpaceTimeStrategy.SqrtN;
/// <summary>
/// Default chunk size for streaming operations
/// </summary>
public int DefaultChunkSize { get; set; } = 1024;
/// <summary>
/// Buffer size for streaming operations
/// </summary>
public int StreamingBufferSize { get; set; } = 8192;
}
/// <summary>
/// Strategies for space-time tradeoffs
/// </summary>
public enum SpaceTimeStrategy
{
/// <summary>Use √n space strategy</summary>
SqrtN,
/// <summary>Use O(1) space strategy</summary>
Constant,
/// <summary>Use O(log n) space strategy</summary>
Logarithmic,
/// <summary>Use O(n) space strategy</summary>
Linear
}

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using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using System.Runtime.CompilerServices;
using System.Text;
using System.Text.Json;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.AspNetCore;
/// <summary>
/// Extensions for streaming large responses with √n memory usage
/// </summary>
public static class SpaceTimeStreamingExtensions
{
/// <summary>
/// Writes a large enumerable as JSON stream with √n buffering
/// </summary>
public static async Task WriteAsJsonStreamAsync<T>(
this HttpResponse response,
IAsyncEnumerable<T> items,
JsonSerializerOptions? options = null,
CancellationToken cancellationToken = default)
{
response.ContentType = "application/json";
response.Headers.Add("X-SpaceTime-Streaming", "sqrtn");
await using var writer = new Utf8JsonWriter(response.Body, new JsonWriterOptions
{
Indented = options?.WriteIndented ?? false
});
writer.WriteStartArray();
var count = 0;
var bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(100_000); // Estimate
var buffer = new List<T>(bufferSize);
await foreach (var item in items.WithCancellation(cancellationToken))
{
buffer.Add(item);
count++;
if (buffer.Count >= bufferSize)
{
await FlushBufferAsync(writer, buffer, options, cancellationToken);
buffer.Clear();
await response.Body.FlushAsync(cancellationToken);
}
}
// Flush remaining items
if (buffer.Count > 0)
{
await FlushBufferAsync(writer, buffer, options, cancellationToken);
}
writer.WriteEndArray();
await writer.FlushAsync(cancellationToken);
}
/// <summary>
/// Creates an async enumerable result with √n chunking
/// </summary>
public static IActionResult StreamWithSqrtNChunking<T>(
this ControllerBase controller,
IAsyncEnumerable<T> items,
int? estimatedCount = null)
{
return new SpaceTimeStreamResult<T>(items, estimatedCount);
}
private static async Task FlushBufferAsync<T>(
Utf8JsonWriter writer,
List<T> buffer,
JsonSerializerOptions? options,
CancellationToken cancellationToken)
{
foreach (var item in buffer)
{
JsonSerializer.Serialize(writer, item, options);
cancellationToken.ThrowIfCancellationRequested();
}
}
}
/// <summary>
/// Action result for streaming with SpaceTime optimizations
/// </summary>
public class SpaceTimeStreamResult<T> : IActionResult
{
private readonly IAsyncEnumerable<T> _items;
private readonly int? _estimatedCount;
public SpaceTimeStreamResult(IAsyncEnumerable<T> items, int? estimatedCount = null)
{
_items = items;
_estimatedCount = estimatedCount;
}
public async Task ExecuteResultAsync(ActionContext context)
{
var response = context.HttpContext.Response;
response.ContentType = "application/json";
response.Headers.Add("X-SpaceTime-Streaming", "chunked");
if (_estimatedCount.HasValue)
{
response.Headers.Add("X-Total-Count", _estimatedCount.Value.ToString());
}
await response.WriteAsJsonStreamAsync(_items, cancellationToken: context.HttpContext.RequestAborted);
}
}
/// <summary>
/// Attribute to configure streaming behavior
/// </summary>
[AttributeUsage(AttributeTargets.Method)]
public class SpaceTimeStreamingAttribute : Attribute
{
/// <summary>
/// Chunk size strategy
/// </summary>
public ChunkStrategy ChunkStrategy { get; set; } = ChunkStrategy.SqrtN;
/// <summary>
/// Custom chunk size (if not using automatic strategies)
/// </summary>
public int? ChunkSize { get; set; }
/// <summary>
/// Whether to include progress headers
/// </summary>
public bool IncludeProgress { get; set; } = true;
}
/// <summary>
/// Strategies for determining chunk size
/// </summary>
public enum ChunkStrategy
{
/// <summary>Use √n of estimated total</summary>
SqrtN,
/// <summary>Fixed size chunks</summary>
Fixed,
/// <summary>Adaptive based on response time</summary>
Adaptive
}
/// <summary>
/// Extensions for streaming file downloads
/// </summary>
public static class FileStreamingExtensions
{
/// <summary>
/// Streams a file with √n buffer size
/// </summary>
public static async Task StreamFileWithSqrtNBufferAsync(
this HttpResponse response,
string filePath,
string? contentType = null,
CancellationToken cancellationToken = default)
{
var fileInfo = new FileInfo(filePath);
if (!fileInfo.Exists)
{
response.StatusCode = 404;
return;
}
var bufferSize = (int)SpaceTimeCalculator.CalculateOptimalBufferSize(
fileInfo.Length,
4 * 1024 * 1024); // Max 4MB buffer
response.ContentType = contentType ?? "application/octet-stream";
response.ContentLength = fileInfo.Length;
response.Headers.Add("X-SpaceTime-Buffer-Size", bufferSize.ToString());
await using var fileStream = new FileStream(
filePath,
FileMode.Open,
FileAccess.Read,
FileShare.Read,
bufferSize,
useAsync: true);
await fileStream.CopyToAsync(response.Body, bufferSize, cancellationToken);
}
}
/// <summary>
/// Middleware for automatic response streaming optimization
/// </summary>
public class ResponseStreamingMiddleware
{
private readonly RequestDelegate _next;
private readonly ResponseStreamingOptions _options;
public ResponseStreamingMiddleware(RequestDelegate next, ResponseStreamingOptions options)
{
_next = next;
_options = options;
}
public async Task InvokeAsync(HttpContext context)
{
// Check if response should be streamed
if (_options.EnableAutoStreaming && IsLargeResponse(context))
{
// Replace response body with buffered stream
var originalBody = context.Response.Body;
using var bufferStream = new SqrtNBufferedStream(originalBody, _options.MaxBufferSize);
context.Response.Body = bufferStream;
try
{
await _next(context);
}
finally
{
context.Response.Body = originalBody;
}
}
else
{
await _next(context);
}
}
private bool IsLargeResponse(HttpContext context)
{
// Check endpoint metadata
var endpoint = context.GetEndpoint();
var streamingAttr = endpoint?.Metadata.GetMetadata<SpaceTimeStreamingAttribute>();
return streamingAttr != null;
}
}
/// <summary>
/// Options for response streaming middleware
/// </summary>
public class ResponseStreamingOptions
{
/// <summary>
/// Enable automatic streaming optimization
/// </summary>
public bool EnableAutoStreaming { get; set; } = true;
/// <summary>
/// Maximum buffer size in bytes
/// </summary>
public int MaxBufferSize { get; set; } = 4 * 1024 * 1024; // 4MB
}
/// <summary>
/// Stream that buffers using √n strategy
/// </summary>
internal class SqrtNBufferedStream : Stream
{
private readonly Stream _innerStream;
private readonly int _bufferSize;
private readonly byte[] _buffer;
private int _bufferPosition;
public SqrtNBufferedStream(Stream innerStream, int maxBufferSize)
{
_innerStream = innerStream;
_bufferSize = Math.Min(maxBufferSize, SpaceTimeCalculator.CalculateSqrtInterval(1_000_000) * 1024);
_buffer = new byte[_bufferSize];
}
public override bool CanRead => _innerStream.CanRead;
public override bool CanSeek => false;
public override bool CanWrite => _innerStream.CanWrite;
public override long Length => throw new NotSupportedException();
public override long Position
{
get => throw new NotSupportedException();
set => throw new NotSupportedException();
}
public override void Flush()
{
if (_bufferPosition > 0)
{
_innerStream.Write(_buffer, 0, _bufferPosition);
_bufferPosition = 0;
}
_innerStream.Flush();
}
public override async Task FlushAsync(CancellationToken cancellationToken)
{
if (_bufferPosition > 0)
{
await _innerStream.WriteAsync(_buffer.AsMemory(0, _bufferPosition), cancellationToken);
_bufferPosition = 0;
}
await _innerStream.FlushAsync(cancellationToken);
}
public override int Read(byte[] buffer, int offset, int count) => throw new NotSupportedException();
public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
public override void SetLength(long value) => throw new NotSupportedException();
public override void Write(byte[] buffer, int offset, int count)
{
while (count > 0)
{
var bytesToCopy = Math.Min(count, _bufferSize - _bufferPosition);
Buffer.BlockCopy(buffer, offset, _buffer, _bufferPosition, bytesToCopy);
_bufferPosition += bytesToCopy;
offset += bytesToCopy;
count -= bytesToCopy;
if (_bufferPosition >= _bufferSize)
{
Flush();
}
}
}
public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
{
var remaining = buffer;
while (remaining.Length > 0)
{
var bytesToCopy = Math.Min(remaining.Length, _bufferSize - _bufferPosition);
remaining.Slice(0, bytesToCopy).CopyTo(_buffer.AsMemory(_bufferPosition));
_bufferPosition += bytesToCopy;
remaining = remaining.Slice(bytesToCopy);
if (_bufferPosition >= _bufferSize)
{
await FlushAsync(cancellationToken);
}
}
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
Flush();
}
base.Dispose(disposing);
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>ASP.NET Core middleware and extensions for SpaceTime optimizations</Description>
<PackageId>SqrtSpace.SpaceTime.AspNetCore</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
<ProjectReference Include="..\SqrtSpace.SpaceTime.Diagnostics\SqrtSpace.SpaceTime.Diagnostics.csproj" />
</ItemGroup>
<ItemGroup>
<FrameworkReference Include="Microsoft.AspNetCore.App" />
</ItemGroup>
</Project>

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Caching.Distributed;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Caching;
/// <summary>
/// Distributed cache implementation with √n space-time tradeoffs
/// </summary>
public class DistributedSpaceTimeCache : IDistributedCache
{
private readonly IDistributedCache _primaryCache;
private readonly IDistributedCache? _secondaryCache;
private readonly SpaceTimeCache<string, byte[]> _localCache;
private readonly ILogger<DistributedSpaceTimeCache> _logger;
private readonly DistributedCacheOptions _options;
private readonly SemaphoreSlim _batchLock;
public DistributedSpaceTimeCache(
IDistributedCache primaryCache,
IDistributedCache? secondaryCache,
ILogger<DistributedSpaceTimeCache> logger,
DistributedCacheOptions? options = null)
{
_primaryCache = primaryCache ?? throw new ArgumentNullException(nameof(primaryCache));
_secondaryCache = secondaryCache;
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_options = options ?? new DistributedCacheOptions();
_localCache = new SpaceTimeCache<string, byte[]>(new SpaceTimeCacheOptions
{
MaxHotCacheSize = _options.LocalCacheSize,
Strategy = MemoryStrategy.SqrtN
});
_batchLock = new SemaphoreSlim(1, 1);
}
public byte[]? Get(string key)
{
return GetAsync(key).GetAwaiter().GetResult();
}
public async Task<byte[]?> GetAsync(string key, CancellationToken token = default)
{
// Try local cache first (L1)
var localValue = await _localCache.GetAsync(key, token);
if (localValue != null)
{
_logger.LogDebug("Cache hit in local cache for key: {Key}", key);
return localValue;
}
// Try primary cache (L2)
try
{
var primaryValue = await _primaryCache.GetAsync(key, token);
if (primaryValue != null)
{
_logger.LogDebug("Cache hit in primary cache for key: {Key}", key);
// Store in local cache for faster access
await _localCache.SetAsync(key, primaryValue, _options.LocalCacheExpiration, cancellationToken: token);
return primaryValue;
}
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Error accessing primary cache for key: {Key}", key);
}
// Try secondary cache if available (L3)
if (_secondaryCache != null)
{
try
{
var secondaryValue = await _secondaryCache.GetAsync(key, token);
if (secondaryValue != null)
{
_logger.LogDebug("Cache hit in secondary cache for key: {Key}", key);
// Promote to primary and local cache
await Task.WhenAll(
_primaryCache.SetAsync(key, secondaryValue, new DistributedCacheEntryOptions
{
SlidingExpiration = _options.DefaultExpiration
}, token),
_localCache.SetAsync(key, secondaryValue, _options.LocalCacheExpiration, cancellationToken: token)
);
return secondaryValue;
}
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Error accessing secondary cache for key: {Key}", key);
}
}
_logger.LogDebug("Cache miss for key: {Key}", key);
return null;
}
public void Set(string key, byte[] value, DistributedCacheEntryOptions options)
{
SetAsync(key, value, options).GetAwaiter().GetResult();
}
public async Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options, CancellationToken token = default)
{
// Determine cache tier based on value size and options
var tier = DetermineCacheTier(value.Length, options);
var tasks = new List<Task>();
// Always set in local cache with shorter expiration
tasks.Add(_localCache.SetAsync(
key,
value,
_options.LocalCacheExpiration,
GetCachePriority(options),
token));
// Set in appropriate distributed tier(s)
switch (tier)
{
case CacheTier.Hot:
tasks.Add(_primaryCache.SetAsync(key, value, options, token));
break;
case CacheTier.Warm:
if (_secondaryCache != null)
{
tasks.Add(_secondaryCache.SetAsync(key, value, options, token));
}
else
{
tasks.Add(_primaryCache.SetAsync(key, value, options, token));
}
break;
case CacheTier.Cold:
// For cold tier, use compressed storage
var compressed = await CompressAsync(value);
var compressedOptions = new DistributedCacheEntryOptions
{
AbsoluteExpiration = options.AbsoluteExpiration,
AbsoluteExpirationRelativeToNow = options.AbsoluteExpirationRelativeToNow,
SlidingExpiration = options.SlidingExpiration
};
if (_secondaryCache != null)
{
tasks.Add(_secondaryCache.SetAsync($"{key}:gz", compressed, compressedOptions, token));
}
else
{
tasks.Add(_primaryCache.SetAsync($"{key}:gz", compressed, compressedOptions, token));
}
break;
}
await Task.WhenAll(tasks);
_logger.LogDebug("Set cache value for key: {Key}, tier: {Tier}, size: {Size} bytes", key, tier, value.Length);
}
public void Refresh(string key)
{
RefreshAsync(key).GetAwaiter().GetResult();
}
public async Task RefreshAsync(string key, CancellationToken token = default)
{
var tasks = new List<Task>
{
_primaryCache.RefreshAsync(key, token)
};
if (_secondaryCache != null)
{
tasks.Add(_secondaryCache.RefreshAsync(key, token));
tasks.Add(_secondaryCache.RefreshAsync($"{key}:gz", token));
}
await Task.WhenAll(tasks);
}
public void Remove(string key)
{
RemoveAsync(key).GetAwaiter().GetResult();
}
public async Task RemoveAsync(string key, CancellationToken token = default)
{
var tasks = new List<Task>
{
_localCache.RemoveAsync(key, token),
_primaryCache.RemoveAsync(key, token)
};
if (_secondaryCache != null)
{
tasks.Add(_secondaryCache.RemoveAsync(key, token));
tasks.Add(_secondaryCache.RemoveAsync($"{key}:gz", token));
}
await Task.WhenAll(tasks);
_logger.LogDebug("Removed cache value for key: {Key}", key);
}
/// <summary>
/// Batch get operation with √n optimization
/// </summary>
public async Task<IDictionary<string, byte[]?>> GetManyAsync(
IEnumerable<string> keys,
CancellationToken cancellationToken = default)
{
var keyList = keys.ToList();
var result = new Dictionary<string, byte[]?>();
// Process in √n batches
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(keyList.Count);
await _batchLock.WaitAsync(cancellationToken);
try
{
foreach (var batch in keyList.Chunk(batchSize))
{
var batchResults = await GetBatchAsync(batch, cancellationToken);
foreach (var kvp in batchResults)
{
result[kvp.Key] = kvp.Value;
}
}
}
finally
{
_batchLock.Release();
}
return result;
}
/// <summary>
/// Batch set operation with √n optimization
/// </summary>
public async Task SetManyAsync(
IDictionary<string, byte[]> values,
DistributedCacheEntryOptions options,
CancellationToken cancellationToken = default)
{
// Process in √n batches
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(values.Count);
await _batchLock.WaitAsync(cancellationToken);
try
{
foreach (var batch in values.Chunk(batchSize))
{
await SetBatchAsync(batch, options, cancellationToken);
}
}
finally
{
_batchLock.Release();
}
}
private async Task<IDictionary<string, byte[]?>> GetBatchAsync(
IEnumerable<string> keys,
CancellationToken cancellationToken)
{
var result = new Dictionary<string, byte[]?>();
var tasks = new List<Task<(string key, byte[]? value)>>();
foreach (var key in keys)
{
tasks.Add(GetWithKeyAsync(key, cancellationToken));
}
var results = await Task.WhenAll(tasks);
foreach (var (key, value) in results)
{
result[key] = value;
}
return result;
}
private async Task<(string key, byte[]? value)> GetWithKeyAsync(string key, CancellationToken cancellationToken)
{
var value = await GetAsync(key, cancellationToken);
return (key, value);
}
private async Task SetBatchAsync(
IEnumerable<KeyValuePair<string, byte[]>> values,
DistributedCacheEntryOptions options,
CancellationToken cancellationToken)
{
var tasks = new List<Task>();
foreach (var kvp in values)
{
tasks.Add(SetAsync(kvp.Key, kvp.Value, options, cancellationToken));
}
await Task.WhenAll(tasks);
}
private CacheTier DetermineCacheTier(int valueSize, DistributedCacheEntryOptions options)
{
// Hot tier: Small, frequently accessed items
if (valueSize < _options.HotTierThreshold)
{
return CacheTier.Hot;
}
// Cold tier: Large, long-lived items
if (valueSize > _options.ColdTierThreshold ||
options.AbsoluteExpirationRelativeToNow > TimeSpan.FromHours(24))
{
return CacheTier.Cold;
}
// Warm tier: Everything else
return CacheTier.Warm;
}
private CacheItemPriority GetCachePriority(DistributedCacheEntryOptions options)
{
if (options.AbsoluteExpirationRelativeToNow < TimeSpan.FromMinutes(5))
{
return CacheItemPriority.Low;
}
if (options.AbsoluteExpirationRelativeToNow > TimeSpan.FromHours(1))
{
return CacheItemPriority.High;
}
return CacheItemPriority.Normal;
}
private async Task<byte[]> CompressAsync(byte[] data)
{
using var output = new System.IO.MemoryStream();
using (var gzip = new System.IO.Compression.GZipStream(output, System.IO.Compression.CompressionLevel.Fastest))
{
await gzip.WriteAsync(data, 0, data.Length);
}
return output.ToArray();
}
private async Task<byte[]> DecompressAsync(byte[] data)
{
using var input = new System.IO.MemoryStream(data);
using var output = new System.IO.MemoryStream();
using (var gzip = new System.IO.Compression.GZipStream(input, System.IO.Compression.CompressionMode.Decompress))
{
await gzip.CopyToAsync(output);
}
return output.ToArray();
}
private enum CacheTier
{
Hot,
Warm,
Cold
}
}
public class DistributedCacheOptions
{
public long LocalCacheSize { get; set; } = 50 * 1024 * 1024; // 50MB
public TimeSpan LocalCacheExpiration { get; set; } = TimeSpan.FromMinutes(5);
public TimeSpan DefaultExpiration { get; set; } = TimeSpan.FromHours(1);
public int HotTierThreshold { get; set; } = 1024; // 1KB
public int ColdTierThreshold { get; set; } = 100 * 1024; // 100KB
public bool EnableCompression { get; set; } = true;
}

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using System.Threading;
using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Caching;
/// <summary>
/// Interface for cold storage in caching systems
/// </summary>
public interface IColdStorage<TKey, TValue>
{
Task<long> CountAsync(CancellationToken cancellationToken = default);
Task<TValue?> ReadAsync(TKey key, CancellationToken cancellationToken = default);
Task WriteAsync(TKey key, TValue value, CancellationToken cancellationToken = default);
Task<bool> DeleteAsync(TKey key, CancellationToken cancellationToken = default);
Task<bool> ExistsAsync(TKey key, CancellationToken cancellationToken = default);
Task ClearAsync(CancellationToken cancellationToken = default);
Task<ColdStorageStatistics> GetStatisticsAsync(CancellationToken cancellationToken = default);
Task CompactAsync(CancellationToken cancellationToken = default);
}
public class ColdStorageStatistics
{
public long ItemCount { get; set; }
public long TotalSize { get; set; }
}

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using System;
using System.Collections.Concurrent;
using System.Linq;
using System.Runtime.Serialization;
using System.Threading;
using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Caching;
/// <summary>
/// In-memory implementation of cold storage for testing
/// </summary>
public class MemoryColdStorage<TKey, TValue> : IColdStorage<TKey, TValue> where TKey : notnull
{
private readonly ConcurrentDictionary<TKey, TValue> _storage = new();
private long _totalSize;
public Task<long> CountAsync(CancellationToken cancellationToken = default)
{
return Task.FromResult((long)_storage.Count);
}
public Task<TValue?> ReadAsync(TKey key, CancellationToken cancellationToken = default)
{
_storage.TryGetValue(key, out var value);
return Task.FromResult(value);
}
public Task WriteAsync(TKey key, TValue value, CancellationToken cancellationToken = default)
{
_storage[key] = value;
// Estimate size
_totalSize += EstimateSize(value);
return Task.CompletedTask;
}
public Task<bool> DeleteAsync(TKey key, CancellationToken cancellationToken = default)
{
if (_storage.TryRemove(key, out var value))
{
_totalSize -= EstimateSize(value);
return Task.FromResult(true);
}
return Task.FromResult(false);
}
public Task<bool> ExistsAsync(TKey key, CancellationToken cancellationToken = default)
{
return Task.FromResult(_storage.ContainsKey(key));
}
public Task ClearAsync(CancellationToken cancellationToken = default)
{
_storage.Clear();
_totalSize = 0;
return Task.CompletedTask;
}
public Task<ColdStorageStatistics> GetStatisticsAsync(CancellationToken cancellationToken = default)
{
return Task.FromResult(new ColdStorageStatistics
{
ItemCount = _storage.Count,
TotalSize = _totalSize
});
}
public Task CompactAsync(CancellationToken cancellationToken = default)
{
// No-op for in-memory storage
return Task.CompletedTask;
}
private long EstimateSize(TValue? value)
{
if (value == null) return 0;
// Simple estimation
return value switch
{
string s => s.Length * 2,
byte[] b => b.Length,
_ => 64 // Default estimate
};
}
}

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using System;
using Microsoft.Extensions.Caching.Distributed;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
namespace SqrtSpace.SpaceTime.Caching;
public static class ServiceCollectionExtensions
{
/// <summary>
/// Adds SpaceTime caching services
/// </summary>
public static IServiceCollection AddSpaceTimeCaching(
this IServiceCollection services,
Action<SpaceTimeCachingOptions>? configure = null)
{
var options = new SpaceTimeCachingOptions();
configure?.Invoke(options);
// Register memory monitor
services.AddSingleton<IMemoryMonitor, DefaultMemoryMonitor>();
// Register cache implementations
services.AddSingleton(typeof(SpaceTimeCache<,>));
// Register distributed cache decorator
services.Decorate<IDistributedCache>((inner, provider) =>
{
var logger = provider.GetRequiredService<ILogger<DistributedSpaceTimeCache>>();
// Get secondary cache if configured
IDistributedCache? secondaryCache = null;
if (options.UseSecondaryCache && options.SecondaryCacheFactory != null)
{
secondaryCache = options.SecondaryCacheFactory(provider);
}
return new DistributedSpaceTimeCache(
inner,
secondaryCache,
logger,
options.DistributedCacheOptions);
});
// Register cache manager
services.AddSingleton<ICacheManager, SpaceTimeCacheManager>();
return services;
}
/// <summary>
/// Adds a named SpaceTime cache
/// </summary>
public static IServiceCollection AddSpaceTimeCache<TKey, TValue>(
this IServiceCollection services,
string name,
Action<SpaceTimeCacheOptions>? configure = null) where TKey : notnull
{
services.AddSingleton(provider =>
{
var options = new SpaceTimeCacheOptions();
configure?.Invoke(options);
var manager = provider.GetRequiredService<ICacheManager>();
return manager.GetOrCreateCache<TKey, TValue>(name, options);
});
return services;
}
private static void Decorate<TInterface>(
this IServiceCollection services,
Func<TInterface, IServiceProvider, TInterface> decorator) where TInterface : class
{
var descriptor = services.FirstOrDefault(s => s.ServiceType == typeof(TInterface));
if (descriptor == null)
{
throw new InvalidOperationException($"Service of type {typeof(TInterface).Name} is not registered.");
}
services.Remove(descriptor);
var decoratedDescriptor = ServiceDescriptor.Describe(
typeof(TInterface),
provider => decorator((TInterface)descriptor.ImplementationFactory!(provider), provider),
descriptor.Lifetime);
services.Add(decoratedDescriptor);
}
}
public class SpaceTimeCachingOptions
{
public bool UseSecondaryCache { get; set; }
public Func<IServiceProvider, IDistributedCache>? SecondaryCacheFactory { get; set; }
public DistributedCacheOptions DistributedCacheOptions { get; set; } = new();
}
public interface ICacheManager
{
SpaceTimeCache<TKey, TValue> GetOrCreateCache<TKey, TValue>(
string name,
SpaceTimeCacheOptions? options = null) where TKey : notnull;
Task<CacheManagerStatistics> GetStatisticsAsync();
Task ClearAllCachesAsync();
}
public class SpaceTimeCacheManager : ICacheManager
{
private readonly Dictionary<string, object> _caches = new();
private readonly SemaphoreSlim _lock = new(1, 1);
public SpaceTimeCache<TKey, TValue> GetOrCreateCache<TKey, TValue>(
string name,
SpaceTimeCacheOptions? options = null) where TKey : notnull
{
_lock.Wait();
try
{
if (_caches.TryGetValue(name, out var existing))
{
return (SpaceTimeCache<TKey, TValue>)existing;
}
var cache = new SpaceTimeCache<TKey, TValue>(options);
_caches[name] = cache;
return cache;
}
finally
{
_lock.Release();
}
}
public async Task<CacheManagerStatistics> GetStatisticsAsync()
{
var stats = new CacheManagerStatistics
{
CacheCount = _caches.Count,
CacheStatistics = new Dictionary<string, CacheStatistics>()
};
foreach (var (name, cache) in _caches)
{
if (cache is IAsyncDisposable asyncDisposable)
{
var method = cache.GetType().GetMethod("GetStatisticsAsync");
if (method != null)
{
var task = (Task<CacheStatistics>)method.Invoke(cache, null)!;
stats.CacheStatistics[name] = await task;
}
}
}
stats.TotalMemoryUsage = stats.CacheStatistics.Values.Sum(s => s.TotalMemoryUsage);
stats.TotalHitRate = stats.CacheStatistics.Values.Average(s => s.HitRate);
return stats;
}
public async Task ClearAllCachesAsync()
{
var tasks = new List<Task>();
foreach (var cache in _caches.Values)
{
var method = cache.GetType().GetMethod("ClearAsync");
if (method != null)
{
tasks.Add((Task)method.Invoke(cache, new object[] { CancellationToken.None })!);
}
}
await Task.WhenAll(tasks);
}
}
public class CacheManagerStatistics
{
public int CacheCount { get; set; }
public Dictionary<string, CacheStatistics> CacheStatistics { get; set; } = new();
public long TotalMemoryUsage { get; set; }
public double TotalHitRate { get; set; }
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Caching;
using System.Threading;
using System.Threading.Tasks;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Caching;
/// <summary>
/// Memory-aware cache that uses √n space-time tradeoffs
/// </summary>
public class SpaceTimeCache<TKey, TValue> : IDisposable where TKey : notnull
{
private readonly ConcurrentDictionary<TKey, CacheEntry> _hotCache;
private readonly IColdStorage<string, CacheEntry> _coldStorage;
private readonly IMemoryMonitor _memoryMonitor;
private readonly SpaceTimeCacheOptions _options;
private readonly SemaphoreSlim _evictionLock;
private readonly Timer _maintenanceTimer;
private long _totalSize;
private long _hitCount;
private long _missCount;
public SpaceTimeCache(SpaceTimeCacheOptions? options = null)
{
_options = options ?? new SpaceTimeCacheOptions();
_hotCache = new ConcurrentDictionary<TKey, CacheEntry>();
_coldStorage = new MemoryColdStorage<string, CacheEntry>();
_memoryMonitor = new DefaultMemoryMonitor();
_evictionLock = new SemaphoreSlim(1, 1);
_maintenanceTimer = new Timer(RunMaintenance, null, TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(1));
}
public long Count => _hotCache.Count + (int)_coldStorage.CountAsync().GetAwaiter().GetResult();
public double HitRate => _hitCount + _missCount == 0 ? 0 : (double)_hitCount / (_hitCount + _missCount);
public long MemoryUsage => _totalSize;
public async Task<TValue?> GetAsync(TKey key, CancellationToken cancellationToken = default)
{
// Check hot cache first
if (_hotCache.TryGetValue(key, out var entry))
{
if (!IsExpired(entry))
{
entry.AccessCount++;
entry.LastAccess = DateTime.UtcNow;
Interlocked.Increment(ref _hitCount);
return entry.Value;
}
else
{
await RemoveAsync(key);
}
}
// Check cold storage
var storageKey = GetStorageKey(key);
var coldEntry = await _coldStorage.ReadAsync(storageKey, cancellationToken);
if (coldEntry != null && !IsExpired(coldEntry))
{
// Promote to hot cache if frequently accessed
if (coldEntry.AccessCount > _options.PromotionThreshold)
{
await PromoteToHotCacheAsync(key, coldEntry);
}
coldEntry.AccessCount++;
coldEntry.LastAccess = DateTime.UtcNow;
await _coldStorage.WriteAsync(storageKey, coldEntry, cancellationToken);
Interlocked.Increment(ref _hitCount);
return coldEntry.Value;
}
Interlocked.Increment(ref _missCount);
return default;
}
public async Task SetAsync(
TKey key,
TValue value,
TimeSpan? expiration = null,
Core.CacheItemPriority priority = Core.CacheItemPriority.Normal,
CancellationToken cancellationToken = default)
{
var entry = new CacheEntry
{
Value = value,
Created = DateTime.UtcNow,
LastAccess = DateTime.UtcNow,
Expiration = expiration.HasValue ? DateTime.UtcNow.Add(expiration.Value) : null,
Priority = priority,
Size = EstimateSize(value)
};
// Decide whether to put in hot or cold cache based on memory pressure
if (await ShouldStoreInHotCacheAsync(entry.Size))
{
_hotCache[key] = entry;
Interlocked.Add(ref _totalSize, entry.Size);
// Trigger eviction if needed
if (_totalSize > _options.MaxHotCacheSize)
{
_ = Task.Run(() => EvictAsync());
}
}
else
{
// Store directly in cold storage
await _coldStorage.WriteAsync(GetStorageKey(key), entry, cancellationToken);
}
}
public async Task<bool> RemoveAsync(TKey key, CancellationToken cancellationToken = default)
{
var removed = false;
if (_hotCache.TryRemove(key, out var entry))
{
Interlocked.Add(ref _totalSize, -entry.Size);
removed = true;
}
if (await _coldStorage.DeleteAsync(GetStorageKey(key), cancellationToken))
{
removed = true;
}
return removed;
}
public async Task<bool> ContainsKeyAsync(TKey key, CancellationToken cancellationToken = default)
{
return _hotCache.ContainsKey(key) ||
await _coldStorage.ExistsAsync(GetStorageKey(key), cancellationToken);
}
public async Task ClearAsync(CancellationToken cancellationToken = default)
{
_hotCache.Clear();
await _coldStorage.ClearAsync(cancellationToken);
_totalSize = 0;
_hitCount = 0;
_missCount = 0;
}
public async Task<CacheStatistics> GetStatisticsAsync()
{
var coldStats = await _coldStorage.GetStatisticsAsync();
return new CacheStatistics
{
HotCacheCount = _hotCache.Count,
ColdCacheCount = (int)coldStats.ItemCount,
TotalMemoryUsage = _totalSize,
ColdStorageUsage = coldStats.TotalSize,
HitRate = HitRate,
HitCount = _hitCount,
MissCount = _missCount,
EvictionCount = _evictionCount,
AverageAccessTime = _accessTimes.Count > 0 ? TimeSpan.FromMilliseconds(_accessTimes.Average()) : TimeSpan.Zero
};
}
private async Task<bool> ShouldStoreInHotCacheAsync(long size)
{
// Use √n strategy: keep √n items in hot cache
var totalItems = Count;
var sqrtN = (int)Math.Sqrt(totalItems);
if (_hotCache.Count >= sqrtN)
{
return false;
}
// Also check memory pressure
var memoryPressure = await _memoryMonitor.GetMemoryPressureAsync();
if (memoryPressure > MemoryPressureLevel.Medium)
{
return false;
}
return _totalSize + size <= _options.MaxHotCacheSize;
}
private long _evictionCount;
private readonly List<double> _accessTimes = new();
private async Task EvictAsync()
{
await _evictionLock.WaitAsync();
try
{
// Calculate how much to evict
var targetSize = (long)(_options.MaxHotCacheSize * 0.8); // Evict to 80% capacity
var toEvict = _totalSize - targetSize;
if (toEvict <= 0) return;
// Get candidates for eviction (LRU with priority consideration)
var candidates = _hotCache
.Select(kvp => new { Key = kvp.Key, Entry = kvp.Value })
.OrderBy(x => GetEvictionScore(x.Entry))
.ToList();
long evicted = 0;
foreach (var candidate in candidates)
{
if (evicted >= toEvict) break;
// Move to cold storage
await _coldStorage.WriteAsync(GetStorageKey(candidate.Key), candidate.Entry);
if (_hotCache.TryRemove(candidate.Key, out var entry))
{
evicted += entry.Size;
Interlocked.Add(ref _totalSize, -entry.Size);
Interlocked.Increment(ref _evictionCount);
}
}
}
finally
{
_evictionLock.Release();
}
}
private double GetEvictionScore(CacheEntry entry)
{
// Lower score = more likely to evict
var age = (DateTime.UtcNow - entry.LastAccess).TotalMinutes;
var frequency = entry.AccessCount;
var priorityWeight = entry.Priority switch
{
Core.CacheItemPriority.Low => 0.5,
Core.CacheItemPriority.Normal => 1.0,
Core.CacheItemPriority.High => 2.0,
Core.CacheItemPriority.NeverRemove => double.MaxValue,
_ => 1.0
};
// LFU-LRU hybrid scoring
return (frequency * priorityWeight) / (age + 1);
}
private async Task PromoteToHotCacheAsync(TKey key, CacheEntry entry)
{
if (await ShouldStoreInHotCacheAsync(entry.Size))
{
_hotCache[key] = entry;
Interlocked.Add(ref _totalSize, entry.Size);
await _coldStorage.DeleteAsync(GetStorageKey(key));
}
}
private bool IsExpired(CacheEntry entry)
{
return entry.Expiration.HasValue && entry.Expiration.Value < DateTime.UtcNow;
}
private string GetStorageKey(TKey key)
{
return $"cache_{key.GetHashCode():X8}_{key}";
}
private long EstimateSize(TValue value)
{
// Simple estimation - override for better accuracy
if (value == null) return 0;
return value switch
{
string s => s.Length * 2,
byte[] b => b.Length,
System.Collections.ICollection c => c.Count * 8,
_ => 64 // Default estimate
};
}
private async void RunMaintenance(object? state)
{
try
{
// Clean up expired entries
var expiredKeys = _hotCache
.Where(kvp => IsExpired(kvp.Value))
.Select(kvp => kvp.Key)
.ToList();
foreach (var key in expiredKeys)
{
await RemoveAsync(key);
}
// Run cold storage cleanup
await _coldStorage.CompactAsync();
}
catch
{
// Log error
}
}
public void Dispose()
{
_maintenanceTimer?.Dispose();
_evictionLock?.Dispose();
if (_coldStorage is IDisposable disposable)
{
disposable.Dispose();
}
}
private class CacheEntry
{
public TValue Value { get; set; } = default!;
public DateTime Created { get; set; }
public DateTime LastAccess { get; set; }
public DateTime? Expiration { get; set; }
public int AccessCount { get; set; }
public Core.CacheItemPriority Priority { get; set; }
public long Size { get; set; }
}
}
public class SpaceTimeCacheOptions
{
public long MaxHotCacheSize { get; set; } = 100 * 1024 * 1024; // 100MB
public string ColdStoragePath { get; set; } = Path.Combine(Path.GetTempPath(), "spacetime_cache");
public int PromotionThreshold { get; set; } = 3;
public TimeSpan DefaultExpiration { get; set; } = TimeSpan.FromHours(1);
public MemoryStrategy Strategy { get; set; } = MemoryStrategy.SqrtN;
}
public class CacheStatistics
{
public int HotCacheCount { get; set; }
public int ColdCacheCount { get; set; }
public long TotalMemoryUsage { get; set; }
public long ColdStorageUsage { get; set; }
public double HitRate { get; set; }
public long HitCount { get; set; }
public long MissCount { get; set; }
public long EvictionCount { get; set; }
public TimeSpan AverageAccessTime { get; set; }
}
public enum MemoryPressureLevel
{
Low = 0,
Medium = 1,
High = 2,
Critical = 3
}
public interface IMemoryMonitor
{
Task<MemoryPressureLevel> GetMemoryPressureAsync();
long GetAvailableMemory();
}
public class DefaultMemoryMonitor : IMemoryMonitor
{
public Task<MemoryPressureLevel> GetMemoryPressureAsync()
{
var memoryInfo = GC.GetTotalMemory(false);
var totalMemory = GC.GetTotalMemory(true);
var usage = (double)memoryInfo / totalMemory;
return Task.FromResult(usage switch
{
< 0.5 => MemoryPressureLevel.Low,
< 0.7 => MemoryPressureLevel.Medium,
< 0.9 => MemoryPressureLevel.High,
_ => MemoryPressureLevel.Critical
});
}
public long GetAvailableMemory()
{
return GC.GetTotalMemory(false);
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory-aware caching with √n space-time tradeoffs for .NET</Description>
<PackageTags>cache;memory;spacetime;distributed;performance</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Caching</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
<PackageReference Include="System.Runtime.Caching" Version="9.0.7" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System.Collections;
using System.Diagnostics.CodeAnalysis;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Collections;
/// <summary>
/// Dictionary that automatically adapts its implementation based on size
/// </summary>
public class AdaptiveDictionary<TKey, TValue> : IDictionary<TKey, TValue>, IReadOnlyDictionary<TKey, TValue> where TKey : notnull
{
private IDictionary<TKey, TValue> _implementation;
private readonly AdaptiveStrategy _strategy;
private readonly IEqualityComparer<TKey> _comparer;
// Thresholds for switching implementations
private const int ArrayThreshold = 16;
private const int DictionaryThreshold = 10_000;
private const int ExternalThreshold = 1_000_000;
/// <summary>
/// Initializes a new adaptive dictionary
/// </summary>
public AdaptiveDictionary() : this(0, null, AdaptiveStrategy.Automatic)
{
}
/// <summary>
/// Initializes a new adaptive dictionary with specified capacity
/// </summary>
public AdaptiveDictionary(int capacity, IEqualityComparer<TKey>? comparer = null, AdaptiveStrategy strategy = AdaptiveStrategy.Automatic)
{
_comparer = comparer ?? EqualityComparer<TKey>.Default;
_strategy = strategy;
_implementation = CreateImplementation(capacity);
}
/// <summary>
/// Gets the current implementation type
/// </summary>
public ImplementationType CurrentImplementation
{
get
{
return _implementation switch
{
ArrayDictionary<TKey, TValue> => ImplementationType.Array,
Dictionary<TKey, TValue> => ImplementationType.Dictionary,
SortedDictionary<TKey, TValue> => ImplementationType.SortedDictionary,
ExternalDictionary<TKey, TValue> => ImplementationType.External,
_ => ImplementationType.Unknown
};
}
}
/// <summary>
/// Gets memory usage statistics
/// </summary>
public MemoryStatistics GetMemoryStatistics()
{
var itemSize = IntPtr.Size * 2; // Rough estimate for key-value pair
var totalSize = Count * itemSize;
var memoryLevel = MemoryHierarchy.DetectSystem().GetOptimalLevel(totalSize);
return new MemoryStatistics
{
ItemCount = Count,
EstimatedMemoryBytes = totalSize,
MemoryLevel = memoryLevel,
Implementation = CurrentImplementation
};
}
#region IDictionary Implementation
public TValue this[TKey key]
{
get => _implementation[key];
set
{
_implementation[key] = value;
AdaptIfNeeded();
}
}
public ICollection<TKey> Keys => _implementation.Keys;
public ICollection<TValue> Values => _implementation.Values;
public int Count => _implementation.Count;
public bool IsReadOnly => _implementation.IsReadOnly;
IEnumerable<TKey> IReadOnlyDictionary<TKey, TValue>.Keys => Keys;
IEnumerable<TValue> IReadOnlyDictionary<TKey, TValue>.Values => Values;
public void Add(TKey key, TValue value)
{
_implementation.Add(key, value);
AdaptIfNeeded();
}
public void Add(KeyValuePair<TKey, TValue> item)
{
_implementation.Add(item);
AdaptIfNeeded();
}
public void Clear()
{
_implementation.Clear();
AdaptIfNeeded();
}
public bool Contains(KeyValuePair<TKey, TValue> item) => _implementation.Contains(item);
public bool ContainsKey(TKey key) => _implementation.ContainsKey(key);
public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex) => _implementation.CopyTo(array, arrayIndex);
public bool Remove(TKey key)
{
var result = _implementation.Remove(key);
AdaptIfNeeded();
return result;
}
public bool Remove(KeyValuePair<TKey, TValue> item)
{
var result = _implementation.Remove(item);
AdaptIfNeeded();
return result;
}
public bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value) => _implementation.TryGetValue(key, out value);
public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() => _implementation.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
#endregion
private void AdaptIfNeeded()
{
if (_strategy != AdaptiveStrategy.Automatic)
return;
IDictionary<TKey, TValue>? newImplementation = Count switch
{
<= ArrayThreshold when CurrentImplementation != ImplementationType.Array =>
new ArrayDictionary<TKey, TValue>(_comparer),
> ArrayThreshold and <= DictionaryThreshold when CurrentImplementation == ImplementationType.Array =>
new Dictionary<TKey, TValue>(_comparer),
> DictionaryThreshold and <= ExternalThreshold when CurrentImplementation != ImplementationType.SortedDictionary =>
new SortedDictionary<TKey, TValue>(Comparer<TKey>.Create((x, y) => _comparer.GetHashCode(x).CompareTo(_comparer.GetHashCode(y)))),
> ExternalThreshold when CurrentImplementation != ImplementationType.External =>
new ExternalDictionary<TKey, TValue>(_comparer),
_ => null
};
if (newImplementation != null)
{
// Copy data to new implementation
foreach (var kvp in _implementation)
{
newImplementation.Add(kvp);
}
// Dispose old implementation if needed
if (_implementation is IDisposable disposable)
{
disposable.Dispose();
}
_implementation = newImplementation;
}
}
private IDictionary<TKey, TValue> CreateImplementation(int capacity)
{
return capacity switch
{
<= ArrayThreshold => new ArrayDictionary<TKey, TValue>(_comparer),
<= DictionaryThreshold => new Dictionary<TKey, TValue>(capacity, _comparer),
<= ExternalThreshold => new SortedDictionary<TKey, TValue>(Comparer<TKey>.Create((x, y) => _comparer.GetHashCode(x).CompareTo(_comparer.GetHashCode(y)))),
_ => new ExternalDictionary<TKey, TValue>(_comparer)
};
}
}
/// <summary>
/// Array-based dictionary for small collections
/// </summary>
internal class ArrayDictionary<TKey, TValue> : IDictionary<TKey, TValue> where TKey : notnull
{
private readonly List<KeyValuePair<TKey, TValue>> _items;
private readonly IEqualityComparer<TKey> _comparer;
public ArrayDictionary(IEqualityComparer<TKey> comparer)
{
_items = new List<KeyValuePair<TKey, TValue>>();
_comparer = comparer;
}
public TValue this[TKey key]
{
get
{
var index = FindIndex(key);
if (index < 0) throw new KeyNotFoundException();
return _items[index].Value;
}
set
{
var index = FindIndex(key);
if (index < 0)
{
_items.Add(new KeyValuePair<TKey, TValue>(key, value));
}
else
{
_items[index] = new KeyValuePair<TKey, TValue>(key, value);
}
}
}
public ICollection<TKey> Keys => _items.Select(kvp => kvp.Key).ToList();
public ICollection<TValue> Values => _items.Select(kvp => kvp.Value).ToList();
public int Count => _items.Count;
public bool IsReadOnly => false;
public void Add(TKey key, TValue value)
{
if (ContainsKey(key)) throw new ArgumentException("Key already exists");
_items.Add(new KeyValuePair<TKey, TValue>(key, value));
}
public void Add(KeyValuePair<TKey, TValue> item)
{
Add(item.Key, item.Value);
}
public void Clear() => _items.Clear();
public bool Contains(KeyValuePair<TKey, TValue> item)
{
var index = FindIndex(item.Key);
return index >= 0 && EqualityComparer<TValue>.Default.Equals(_items[index].Value, item.Value);
}
public bool ContainsKey(TKey key) => FindIndex(key) >= 0;
public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
{
_items.CopyTo(array, arrayIndex);
}
public bool Remove(TKey key)
{
var index = FindIndex(key);
if (index < 0) return false;
_items.RemoveAt(index);
return true;
}
public bool Remove(KeyValuePair<TKey, TValue> item)
{
return _items.Remove(item);
}
public bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value)
{
var index = FindIndex(key);
if (index < 0)
{
value = default;
return false;
}
value = _items[index].Value;
return true;
}
public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() => _items.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
private int FindIndex(TKey key)
{
for (int i = 0; i < _items.Count; i++)
{
if (_comparer.Equals(_items[i].Key, key))
return i;
}
return -1;
}
}
/// <summary>
/// External dictionary for very large collections
/// </summary>
internal class ExternalDictionary<TKey, TValue> : IDictionary<TKey, TValue>, IDisposable where TKey : notnull
{
private readonly Dictionary<TKey, TValue> _cache;
private readonly ExternalStorage<KeyValuePair<TKey, TValue>> _storage;
private readonly IEqualityComparer<TKey> _comparer;
private readonly int _cacheSize;
private int _totalCount;
public ExternalDictionary(IEqualityComparer<TKey> comparer)
{
_comparer = comparer;
_cache = new Dictionary<TKey, TValue>(_comparer);
_storage = new ExternalStorage<KeyValuePair<TKey, TValue>>();
_cacheSize = SpaceTimeCalculator.CalculateSqrtInterval(1_000_000);
}
public TValue this[TKey key]
{
get
{
if (_cache.TryGetValue(key, out var value))
return value;
// Search in external storage
foreach (var kvp in ReadAllFromStorage())
{
if (_comparer.Equals(kvp.Key, key))
return kvp.Value;
}
throw new KeyNotFoundException();
}
set
{
if (_cache.Count >= _cacheSize)
{
SpillCacheToDisk();
}
_cache[key] = value;
_totalCount = Math.Max(_totalCount, _cache.Count);
}
}
public ICollection<TKey> Keys => throw new NotSupportedException("Keys collection not supported for external dictionary");
public ICollection<TValue> Values => throw new NotSupportedException("Values collection not supported for external dictionary");
public int Count => _totalCount;
public bool IsReadOnly => false;
public void Add(TKey key, TValue value)
{
if (ContainsKey(key)) throw new ArgumentException("Key already exists");
this[key] = value;
}
public void Add(KeyValuePair<TKey, TValue> item) => Add(item.Key, item.Value);
public void Clear()
{
_cache.Clear();
_storage.Dispose();
_totalCount = 0;
}
public bool Contains(KeyValuePair<TKey, TValue> item) => ContainsKey(item.Key);
public bool ContainsKey(TKey key) => _cache.ContainsKey(key) || ExistsInStorage(key);
public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex) => throw new NotSupportedException();
public bool Remove(TKey key) => _cache.Remove(key);
public bool Remove(KeyValuePair<TKey, TValue> item) => Remove(item.Key);
public bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value)
{
try
{
value = this[key];
return true;
}
catch (KeyNotFoundException)
{
value = default;
return false;
}
}
public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
{
foreach (var kvp in _cache)
yield return kvp;
foreach (var kvp in ReadAllFromStorage())
yield return kvp;
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
public void Dispose() => _storage.Dispose();
private void SpillCacheToDisk()
{
_storage.SpillToDiskAsync(_cache).GetAwaiter().GetResult();
_cache.Clear();
}
private bool ExistsInStorage(TKey key)
{
foreach (var kvp in ReadAllFromStorage())
{
if (_comparer.Equals(kvp.Key, key))
return true;
}
return false;
}
private IEnumerable<KeyValuePair<TKey, TValue>> ReadAllFromStorage()
{
// This is simplified - production would be more efficient
return Enumerable.Empty<KeyValuePair<TKey, TValue>>();
}
}
/// <summary>
/// Implementation type of adaptive collection
/// </summary>
public enum ImplementationType
{
Unknown,
Array,
Dictionary,
SortedDictionary,
External
}
/// <summary>
/// Memory usage statistics
/// </summary>
public class MemoryStatistics
{
public int ItemCount { get; init; }
public long EstimatedMemoryBytes { get; init; }
public MemoryLevel MemoryLevel { get; init; }
public ImplementationType Implementation { get; init; }
}
/// <summary>
/// Strategy for adaptive collections
/// </summary>
public enum AdaptiveStrategy
{
/// <summary>Automatically adapt based on size</summary>
Automatic,
/// <summary>Always use array implementation</summary>
ForceArray,
/// <summary>Always use dictionary implementation</summary>
ForceDictionary,
/// <summary>Always use external implementation</summary>
ForceExternal
}

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using System.Collections;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Collections;
/// <summary>
/// List that automatically adapts its implementation based on size and usage patterns
/// </summary>
public class AdaptiveList<T> : IList<T>, IReadOnlyList<T>
{
private IList<T> _implementation;
private readonly AdaptiveStrategy _strategy;
private AccessPattern _accessPattern = AccessPattern.Unknown;
private int _sequentialAccesses;
private int _randomAccesses;
// Thresholds for switching implementations
private const int ArrayThreshold = 1000;
private const int LinkedListThreshold = 10_000;
private const int ExternalThreshold = 1_000_000;
/// <summary>
/// Initializes a new adaptive list
/// </summary>
public AdaptiveList() : this(0, AdaptiveStrategy.Automatic)
{
}
/// <summary>
/// Initializes a new adaptive list with specified capacity
/// </summary>
public AdaptiveList(int capacity, AdaptiveStrategy strategy = AdaptiveStrategy.Automatic)
{
_strategy = strategy;
_implementation = CreateImplementation(capacity);
}
/// <summary>
/// Gets the current implementation type
/// </summary>
public string CurrentImplementation => _implementation switch
{
List<T> => "List<T>",
LinkedList<T> => "LinkedList<T>",
SortedSet<T> => "SortedSet<T>",
ExternalList<T> => "ExternalList<T>",
_ => "Unknown"
};
/// <summary>
/// Gets the detected access pattern
/// </summary>
public AccessPattern DetectedAccessPattern => _accessPattern;
#region IList Implementation
public T this[int index]
{
get
{
RecordAccess(index);
return _implementation[index];
}
set
{
RecordAccess(index);
_implementation[index] = value;
}
}
public int Count => _implementation.Count;
public bool IsReadOnly => _implementation.IsReadOnly;
public void Add(T item)
{
_implementation.Add(item);
AdaptIfNeeded();
}
public void Clear()
{
_implementation.Clear();
_accessPattern = AccessPattern.Unknown;
_sequentialAccesses = 0;
_randomAccesses = 0;
}
public bool Contains(T item) => _implementation.Contains(item);
public void CopyTo(T[] array, int arrayIndex) => _implementation.CopyTo(array, arrayIndex);
public int IndexOf(T item) => _implementation.IndexOf(item);
public void Insert(int index, T item)
{
RecordAccess(index);
_implementation.Insert(index, item);
AdaptIfNeeded();
}
public bool Remove(T item)
{
var result = _implementation.Remove(item);
AdaptIfNeeded();
return result;
}
public void RemoveAt(int index)
{
RecordAccess(index);
_implementation.RemoveAt(index);
AdaptIfNeeded();
}
public IEnumerator<T> GetEnumerator() => _implementation.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
#endregion
/// <summary>
/// Provides a batch operation for adding multiple items efficiently
/// </summary>
public void AddRange(IEnumerable<T> items)
{
if (_implementation is List<T> list)
{
list.AddRange(items);
}
else
{
foreach (var item in items)
{
Add(item);
}
}
AdaptIfNeeded();
}
/// <summary>
/// Process items in √n-sized batches
/// </summary>
public IEnumerable<IReadOnlyList<T>> GetBatches()
{
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(Count);
for (int i = 0; i < Count; i += batchSize)
{
var batch = new List<T>(Math.Min(batchSize, Count - i));
for (int j = i; j < Math.Min(i + batchSize, Count); j++)
{
batch.Add(this[j]);
}
yield return batch;
}
}
private void RecordAccess(int index)
{
if (index == Count - 1 || index == _sequentialAccesses)
{
_sequentialAccesses++;
}
else
{
_randomAccesses++;
}
// Update access pattern detection
var totalAccesses = _sequentialAccesses + _randomAccesses;
if (totalAccesses > 100)
{
var sequentialRatio = (double)_sequentialAccesses / totalAccesses;
_accessPattern = sequentialRatio > 0.8 ? AccessPattern.Sequential : AccessPattern.Random;
}
}
private void AdaptIfNeeded()
{
if (_strategy != AdaptiveStrategy.Automatic)
return;
IList<T>? newImplementation = null;
// Decide based on size and access pattern
if (Count > ExternalThreshold && !(_implementation is ExternalList<T>))
{
newImplementation = new ExternalList<T>();
}
else if (Count > LinkedListThreshold && _accessPattern == AccessPattern.Sequential && !(_implementation is LinkedList<T>))
{
// LinkedList is good for sequential access with many insertions/deletions
var linkedList = new LinkedList<T>();
foreach (var item in _implementation)
{
linkedList.AddLast(item);
}
newImplementation = new LinkedListAdapter<T>(linkedList);
}
else if (Count <= ArrayThreshold && !(_implementation is List<T>))
{
newImplementation = new List<T>(_implementation);
}
if (newImplementation != null)
{
// Dispose old implementation if needed
if (_implementation is IDisposable disposable)
{
disposable.Dispose();
}
_implementation = newImplementation;
}
}
private IList<T> CreateImplementation(int capacity)
{
return capacity switch
{
<= ArrayThreshold => new List<T>(capacity),
<= ExternalThreshold => new List<T>(capacity),
_ => new ExternalList<T>()
};
}
}
/// <summary>
/// Adapter to make LinkedList work as IList
/// </summary>
internal class LinkedListAdapter<T> : IList<T>
{
private readonly LinkedList<T> _list;
public LinkedListAdapter(LinkedList<T> list)
{
_list = list;
}
public T this[int index]
{
get => GetNodeAt(index).Value;
set => GetNodeAt(index).Value = value;
}
public int Count => _list.Count;
public bool IsReadOnly => false;
public void Add(T item) => _list.AddLast(item);
public void Clear() => _list.Clear();
public bool Contains(T item) => _list.Contains(item);
public void CopyTo(T[] array, int arrayIndex)
{
_list.CopyTo(array, arrayIndex);
}
public int IndexOf(T item)
{
var index = 0;
foreach (var value in _list)
{
if (EqualityComparer<T>.Default.Equals(value, item))
return index;
index++;
}
return -1;
}
public void Insert(int index, T item)
{
if (index == Count)
{
_list.AddLast(item);
}
else
{
var node = GetNodeAt(index);
_list.AddBefore(node, item);
}
}
public bool Remove(T item) => _list.Remove(item);
public void RemoveAt(int index)
{
var node = GetNodeAt(index);
_list.Remove(node);
}
public IEnumerator<T> GetEnumerator() => _list.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
private LinkedListNode<T> GetNodeAt(int index)
{
if (index < 0 || index >= Count)
throw new ArgumentOutOfRangeException(nameof(index));
var node = _list.First;
for (int i = 0; i < index; i++)
{
node = node!.Next;
}
return node!;
}
}
/// <summary>
/// External list for very large collections
/// </summary>
internal class ExternalList<T> : IList<T>, IDisposable
{
private readonly List<T> _cache;
private readonly ExternalStorage<T> _storage;
private readonly int _cacheSize;
private int _totalCount;
private readonly List<string> _spillFiles = new();
public ExternalList()
{
_cache = new List<T>();
_storage = new ExternalStorage<T>();
_cacheSize = SpaceTimeCalculator.CalculateSqrtInterval(1_000_000);
}
public T this[int index]
{
get
{
if (index < _cache.Count)
return _cache[index];
// Load from external storage
throw new NotImplementedException("External storage access not implemented");
}
set
{
if (index < _cache.Count)
_cache[index] = value;
else
throw new NotImplementedException("External storage modification not implemented");
}
}
public int Count => _totalCount;
public bool IsReadOnly => false;
public void Add(T item)
{
if (_cache.Count >= _cacheSize)
{
SpillCacheToDisk();
}
_cache.Add(item);
_totalCount++;
}
public void Clear()
{
_cache.Clear();
_storage.Dispose();
_spillFiles.Clear();
_totalCount = 0;
}
public bool Contains(T item) => _cache.Contains(item);
public void CopyTo(T[] array, int arrayIndex) => throw new NotSupportedException();
public int IndexOf(T item) => _cache.IndexOf(item);
public void Insert(int index, T item) => throw new NotSupportedException();
public bool Remove(T item) => _cache.Remove(item);
public void RemoveAt(int index) => throw new NotSupportedException();
public IEnumerator<T> GetEnumerator()
{
foreach (var item in _cache)
yield return item;
foreach (var spillFile in _spillFiles)
{
foreach (var item in _storage.ReadFromDiskAsync(spillFile).ToBlockingEnumerable())
{
yield return item;
}
}
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
public void Dispose() => _storage.Dispose();
private void SpillCacheToDisk()
{
var spillFile = _storage.SpillToDiskAsync(_cache).GetAwaiter().GetResult();
_spillFiles.Add(spillFile);
_cache.Clear();
}
}
/// <summary>
/// Access pattern for adaptive collections
/// </summary>
public enum AccessPattern
{
Unknown,
Sequential,
Random,
Mixed
}
/// <summary>
/// Extension to convert async enumerable to blocking
/// </summary>
internal static class AsyncEnumerableExtensions
{
public static IEnumerable<T> ToBlockingEnumerable<T>(this IAsyncEnumerable<T> source)
{
var enumerator = source.GetAsyncEnumerator();
try
{
while (enumerator.MoveNextAsync().AsTask().GetAwaiter().GetResult())
{
yield return enumerator.Current;
}
}
finally
{
enumerator.DisposeAsync().AsTask().GetAwaiter().GetResult();
}
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory-efficient collections that automatically adapt between implementations based on size</Description>
<PackageId>SqrtSpace.SpaceTime.Collections</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
namespace SqrtSpace.SpaceTime.Configuration;
/// <summary>
/// Manages SpaceTime configuration and policies
/// </summary>
public interface ISpaceTimeConfigurationManager
{
/// <summary>
/// Get the current configuration
/// </summary>
SpaceTimeConfiguration CurrentConfiguration { get; }
/// <summary>
/// Register a configuration change handler
/// </summary>
IDisposable OnConfigurationChanged(Action<SpaceTimeConfiguration> handler);
/// <summary>
/// Apply a configuration override
/// </summary>
void ApplyOverride(string path, object value);
/// <summary>
/// Remove a configuration override
/// </summary>
void RemoveOverride(string path);
/// <summary>
/// Get algorithm policy for an operation
/// </summary>
AlgorithmPolicy GetAlgorithmPolicy(string operationType);
/// <summary>
/// Select algorithm based on context
/// </summary>
AlgorithmChoice SelectAlgorithm(AlgorithmContext context);
/// <summary>
/// Calculate buffer size based on data size
/// </summary>
int CalculateBufferSize(long dataSize);
}
/// <summary>
/// Default implementation of configuration manager
/// </summary>
public class SpaceTimeConfigurationManager : ISpaceTimeConfigurationManager, IHostedService
{
private readonly IOptionsMonitor<SpaceTimeConfiguration> _optionsMonitor;
private readonly ILogger<SpaceTimeConfigurationManager> _logger;
private readonly ConcurrentDictionary<string, object> _overrides;
private readonly List<IDisposable> _changeHandlers;
private readonly AdaptiveAlgorithmSelector _adaptiveSelector;
private SpaceTimeConfiguration _currentConfiguration;
private readonly object _configLock = new();
public SpaceTimeConfiguration CurrentConfiguration
{
get
{
lock (_configLock)
{
return _currentConfiguration;
}
}
}
public SpaceTimeConfigurationManager(
IOptionsMonitor<SpaceTimeConfiguration> optionsMonitor,
ILogger<SpaceTimeConfigurationManager> logger)
{
_optionsMonitor = optionsMonitor ?? throw new ArgumentNullException(nameof(optionsMonitor));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_overrides = new ConcurrentDictionary<string, object>();
_changeHandlers = new List<IDisposable>();
_adaptiveSelector = new AdaptiveAlgorithmSelector();
_currentConfiguration = ApplyOverrides(_optionsMonitor.CurrentValue);
// Subscribe to configuration changes
_optionsMonitor.OnChange(config =>
{
lock (_configLock)
{
_currentConfiguration = ApplyOverrides(config);
}
});
}
public IDisposable OnConfigurationChanged(Action<SpaceTimeConfiguration> handler)
{
if (handler == null)
throw new ArgumentNullException(nameof(handler));
var disposable = _optionsMonitor.OnChange(config =>
{
var configWithOverrides = ApplyOverrides(config);
handler(configWithOverrides);
});
_changeHandlers.Add(disposable);
return new ChangeHandlerDisposable(this, disposable);
}
public void ApplyOverride(string path, object value)
{
if (string.IsNullOrEmpty(path))
throw new ArgumentException("Path cannot be null or empty", nameof(path));
_overrides[path] = value;
lock (_configLock)
{
_currentConfiguration = ApplyOverrides(_optionsMonitor.CurrentValue);
}
_logger.LogInformation("Applied configuration override: {Path} = {Value}", path, value);
}
public void RemoveOverride(string path)
{
if (_overrides.TryRemove(path, out _))
{
lock (_configLock)
{
_currentConfiguration = ApplyOverrides(_optionsMonitor.CurrentValue);
}
_logger.LogInformation("Removed configuration override: {Path}", path);
}
}
public AlgorithmPolicy GetAlgorithmPolicy(string operationType)
{
if (CurrentConfiguration.Algorithms.Policies.TryGetValue(operationType, out var policy))
{
return policy;
}
// Return default policy
return new AlgorithmPolicy
{
PreferExternal = false,
SizeThreshold = CurrentConfiguration.Algorithms.MinExternalAlgorithmSize,
MaxMemoryFactor = 0.5
};
}
public AlgorithmChoice SelectAlgorithm(AlgorithmContext context)
{
var policy = GetAlgorithmPolicy(context.OperationType);
// Use custom selector if available
if (policy.CustomSelector != null)
{
return policy.CustomSelector(context);
}
// Use adaptive selection if enabled
if (CurrentConfiguration.Algorithms.EnableAdaptiveSelection)
{
var adaptiveChoice = _adaptiveSelector.SelectAlgorithm(
context,
policy,
CurrentConfiguration.Algorithms.AdaptiveLearningRate);
if (adaptiveChoice.HasValue)
return adaptiveChoice.Value;
}
// Default selection logic
var memoryUsage = context.DataSize * policy.MaxMemoryFactor;
var availableMemory = context.AvailableMemory * (1 - context.CurrentMemoryPressure);
if (context.DataSize < policy.SizeThreshold && memoryUsage < availableMemory)
{
return AlgorithmChoice.InMemory;
}
if (policy.PreferExternal || memoryUsage > availableMemory)
{
return AlgorithmChoice.External;
}
return AlgorithmChoice.Hybrid;
}
public int CalculateBufferSize(long dataSize)
{
var strategy = CurrentConfiguration.Memory.BufferSizeStrategy;
return strategy switch
{
BufferSizeStrategy.Sqrt => (int)Math.Sqrt(dataSize),
BufferSizeStrategy.Fixed => 65536, // 64KB default
BufferSizeStrategy.Logarithmic => (int)(Math.Log(dataSize) * 1000),
BufferSizeStrategy.Custom => CurrentConfiguration.Memory.CustomBufferSizeCalculator?.Invoke(dataSize) ?? 65536,
_ => 65536
};
}
private SpaceTimeConfiguration ApplyOverrides(SpaceTimeConfiguration baseConfig)
{
if (!_overrides.Any())
return baseConfig;
// Clone the configuration
var config = System.Text.Json.JsonSerializer.Deserialize<SpaceTimeConfiguration>(
System.Text.Json.JsonSerializer.Serialize(baseConfig))!;
// Apply overrides
foreach (var (path, value) in _overrides)
{
ApplyOverrideToObject(config, path, value);
}
return config;
}
private void ApplyOverrideToObject(object target, string path, object value)
{
var segments = path.Split('.');
var current = target;
for (int i = 0; i < segments.Length - 1; i++)
{
var property = current.GetType().GetProperty(segments[i]);
if (property == null)
{
_logger.LogWarning("Property {Property} not found in path {Path}", segments[i], path);
return;
}
current = property.GetValue(current)!;
if (current == null)
{
_logger.LogWarning("Null value encountered at {Property} in path {Path}", segments[i], path);
return;
}
}
var finalProperty = current.GetType().GetProperty(segments[^1]);
if (finalProperty == null)
{
_logger.LogWarning("Property {Property} not found in path {Path}", segments[^1], path);
return;
}
try
{
finalProperty.SetValue(current, Convert.ChangeType(value, finalProperty.PropertyType));
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to set override value for {Path}", path);
}
}
public Task StartAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("SpaceTime Configuration Manager started");
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
foreach (var handler in _changeHandlers)
{
handler.Dispose();
}
_changeHandlers.Clear();
_logger.LogInformation("SpaceTime Configuration Manager stopped");
return Task.CompletedTask;
}
private class ChangeHandlerDisposable : IDisposable
{
private readonly SpaceTimeConfigurationManager _manager;
private readonly IDisposable _innerDisposable;
public ChangeHandlerDisposable(SpaceTimeConfigurationManager manager, IDisposable innerDisposable)
{
_manager = manager;
_innerDisposable = innerDisposable;
}
public void Dispose()
{
_innerDisposable.Dispose();
_manager._changeHandlers.Remove(_innerDisposable);
}
}
}
/// <summary>
/// Adaptive algorithm selector with learning capabilities
/// </summary>
internal class AdaptiveAlgorithmSelector
{
private readonly ConcurrentDictionary<string, AlgorithmStatistics> _statistics;
public AdaptiveAlgorithmSelector()
{
_statistics = new ConcurrentDictionary<string, AlgorithmStatistics>();
}
public AlgorithmChoice? SelectAlgorithm(
AlgorithmContext context,
AlgorithmPolicy policy,
double learningRate)
{
var key = $"{context.OperationType}_{GetSizeCategory(context.DataSize)}";
if (!_statistics.TryGetValue(key, out var stats))
{
return null; // No adaptive data yet
}
// Calculate scores based on historical performance
var inMemoryScore = stats.InMemorySuccessRate * (1 - stats.InMemoryAverageMemoryPressure);
var externalScore = stats.ExternalSuccessRate * stats.ExternalAverageSpeedRatio;
var hybridScore = stats.HybridSuccessRate * stats.HybridAverageEfficiency;
// Apply learning rate to adjust for recent performance
if (inMemoryScore > externalScore && inMemoryScore > hybridScore)
return AlgorithmChoice.InMemory;
if (externalScore > hybridScore)
return AlgorithmChoice.External;
return AlgorithmChoice.Hybrid;
}
public void RecordOutcome(
AlgorithmContext context,
AlgorithmChoice choice,
AlgorithmOutcome outcome)
{
var key = $"{context.OperationType}_{GetSizeCategory(context.DataSize)}";
_statistics.AddOrUpdate(key,
k => new AlgorithmStatistics { LastUpdated = DateTime.UtcNow },
(k, stats) =>
{
stats.UpdateStatistics(choice, outcome);
return stats;
});
}
private string GetSizeCategory(long size)
{
return size switch
{
< 1_000_000 => "small",
< 100_000_000 => "medium",
< 1_000_000_000 => "large",
_ => "xlarge"
};
}
}
internal class AlgorithmStatistics
{
public double InMemorySuccessRate { get; set; } = 0.5;
public double InMemoryAverageMemoryPressure { get; set; } = 0.5;
public double ExternalSuccessRate { get; set; } = 0.5;
public double ExternalAverageSpeedRatio { get; set; } = 0.5;
public double HybridSuccessRate { get; set; } = 0.5;
public double HybridAverageEfficiency { get; set; } = 0.5;
public DateTime LastUpdated { get; set; }
private const double DecayFactor = 0.95;
public void UpdateStatistics(AlgorithmChoice choice, AlgorithmOutcome outcome)
{
// Apply time decay to existing statistics
var timeSinceUpdate = DateTime.UtcNow - LastUpdated;
var decay = Math.Pow(DecayFactor, timeSinceUpdate.TotalDays);
InMemorySuccessRate *= decay;
ExternalSuccessRate *= decay;
HybridSuccessRate *= decay;
// Update statistics based on outcome
switch (choice)
{
case AlgorithmChoice.InMemory:
InMemorySuccessRate = (InMemorySuccessRate + (outcome.Success ? 1 : 0)) / 2;
InMemoryAverageMemoryPressure = (InMemoryAverageMemoryPressure + outcome.MemoryPressure) / 2;
break;
case AlgorithmChoice.External:
ExternalSuccessRate = (ExternalSuccessRate + (outcome.Success ? 1 : 0)) / 2;
ExternalAverageSpeedRatio = (ExternalAverageSpeedRatio + outcome.SpeedRatio) / 2;
break;
case AlgorithmChoice.Hybrid:
HybridSuccessRate = (HybridSuccessRate + (outcome.Success ? 1 : 0)) / 2;
HybridAverageEfficiency = (HybridAverageEfficiency + outcome.Efficiency) / 2;
break;
}
LastUpdated = DateTime.UtcNow;
}
}
public class AlgorithmOutcome
{
public bool Success { get; set; }
public double MemoryPressure { get; set; }
public double SpeedRatio { get; set; } // Compared to baseline
public double Efficiency { get; set; } // Combined metric
public TimeSpan Duration { get; set; }
public Exception? Error { get; set; }
}

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using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Configuration.Policies;
/// <summary>
/// Policy engine for evaluating SpaceTime optimization rules
/// </summary>
public interface IPolicyEngine
{
/// <summary>
/// Evaluate if a policy applies to the given context
/// </summary>
Task<bool> EvaluateAsync(string policyName, PolicyContext context);
/// <summary>
/// Register a new policy
/// </summary>
void RegisterPolicy(string name, IPolicy policy);
}
/// <summary>
/// Context for policy evaluation
/// </summary>
public class PolicyContext
{
public long DataSize { get; set; }
public long AvailableMemory { get; set; }
public string OperationType { get; set; } = string.Empty;
public int ConcurrentOperations { get; set; }
}
/// <summary>
/// Base policy interface
/// </summary>
public interface IPolicy
{
Task<bool> EvaluateAsync(PolicyContext context);
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
namespace SqrtSpace.SpaceTime.Configuration.Policies;
/// <summary>
/// Rule-based policy engine for SpaceTime optimizations
/// </summary>
public interface IRulePolicyEngine
{
/// <summary>
/// Evaluate policies for a given context
/// </summary>
Task<PolicyResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default);
/// <summary>
/// Register a policy rule
/// </summary>
void RegisterRule(IPolicyRule rule);
/// <summary>
/// Remove a policy rule
/// </summary>
void UnregisterRule(string ruleName);
/// <summary>
/// Get all registered rules
/// </summary>
IEnumerable<IPolicyRule> GetRules();
}
/// <summary>
/// Extended context for policy evaluation with rules
/// </summary>
public class RulePolicyContext
{
public string OperationType { get; set; } = "";
public long DataSize { get; set; }
public long AvailableMemory { get; set; }
public double CurrentMemoryPressure { get; set; }
public int ConcurrentOperations { get; set; }
public TimeSpan? ExpectedDuration { get; set; }
public Dictionary<string, object> Properties { get; set; } = new();
}
/// <summary>
/// Result of policy evaluation
/// </summary>
public class PolicyResult
{
public bool ShouldProceed { get; set; } = true;
public List<PolicyAction> Actions { get; set; } = new();
public Dictionary<string, object> Recommendations { get; set; } = new();
public List<string> AppliedRules { get; set; } = new();
public List<PolicyViolation> Violations { get; set; } = new();
}
/// <summary>
/// Action to be taken based on policy
/// </summary>
public class PolicyAction
{
public string ActionType { get; set; } = "";
public Dictionary<string, object> Parameters { get; set; } = new();
public int Priority { get; set; }
}
/// <summary>
/// Policy violation details
/// </summary>
public class PolicyViolation
{
public string RuleName { get; set; } = "";
public string Description { get; set; } = "";
public PolicySeverity Severity { get; set; }
public Dictionary<string, object> Details { get; set; } = new();
}
public enum PolicySeverity
{
Info,
Warning,
Error,
Critical
}
/// <summary>
/// Interface for policy rules
/// </summary>
public interface IPolicyRule
{
string Name { get; }
int Priority { get; }
bool IsEnabled { get; set; }
Task<RuleResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default);
}
/// <summary>
/// Result from a single rule evaluation
/// </summary>
public class RuleResult
{
public bool Passed { get; set; } = true;
public List<PolicyAction> Actions { get; set; } = new();
public Dictionary<string, object> Recommendations { get; set; } = new();
public PolicyViolation? Violation { get; set; }
}
/// <summary>
/// Default implementation of policy engine
/// </summary>
public class PolicyEngine : IRulePolicyEngine
{
private readonly Dictionary<string, IPolicyRule> _rules;
private readonly ILogger<PolicyEngine> _logger;
private readonly ReaderWriterLockSlim _rulesLock;
public PolicyEngine(ILogger<PolicyEngine> logger)
{
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_rules = new Dictionary<string, IPolicyRule>();
_rulesLock = new ReaderWriterLockSlim();
// Register default rules
RegisterDefaultRules();
}
public async Task<PolicyResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default)
{
var result = new PolicyResult();
var tasks = new List<Task<(string ruleName, RuleResult ruleResult)>>();
_rulesLock.EnterReadLock();
try
{
// Get enabled rules sorted by priority
var enabledRules = _rules.Values
.Where(r => r.IsEnabled)
.OrderByDescending(r => r.Priority)
.ToList();
// Evaluate rules in parallel
foreach (var rule in enabledRules)
{
var ruleCopy = rule; // Capture for closure
tasks.Add(Task.Run(async () =>
{
try
{
var ruleResult = await ruleCopy.EvaluateAsync(context, cancellationToken);
return (ruleCopy.Name, ruleResult);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error evaluating rule {RuleName}", ruleCopy.Name);
return (ruleCopy.Name, new RuleResult { Passed = true }); // Fail open
}
}, cancellationToken));
}
}
finally
{
_rulesLock.ExitReadLock();
}
// Wait for all rules to complete
var results = await Task.WhenAll(tasks);
// Aggregate results
foreach (var (ruleName, ruleResult) in results)
{
if (!ruleResult.Passed)
{
result.ShouldProceed = false;
if (ruleResult.Violation != null)
{
result.Violations.Add(ruleResult.Violation);
}
}
if (ruleResult.Actions.Any())
{
result.Actions.AddRange(ruleResult.Actions);
}
foreach (var (key, value) in ruleResult.Recommendations)
{
result.Recommendations[key] = value;
}
result.AppliedRules.Add(ruleName);
}
// Sort actions by priority
result.Actions = result.Actions
.OrderByDescending(a => a.Priority)
.ToList();
_logger.LogDebug("Policy evaluation completed: {RuleCount} rules applied, Proceed: {ShouldProceed}",
result.AppliedRules.Count, result.ShouldProceed);
return result;
}
public void RegisterRule(IPolicyRule rule)
{
if (rule == null)
throw new ArgumentNullException(nameof(rule));
_rulesLock.EnterWriteLock();
try
{
_rules[rule.Name] = rule;
_logger.LogInformation("Registered policy rule: {RuleName}", rule.Name);
}
finally
{
_rulesLock.ExitWriteLock();
}
}
public void UnregisterRule(string ruleName)
{
_rulesLock.EnterWriteLock();
try
{
if (_rules.Remove(ruleName))
{
_logger.LogInformation("Unregistered policy rule: {RuleName}", ruleName);
}
}
finally
{
_rulesLock.ExitWriteLock();
}
}
public IEnumerable<IPolicyRule> GetRules()
{
_rulesLock.EnterReadLock();
try
{
return _rules.Values.ToList();
}
finally
{
_rulesLock.ExitReadLock();
}
}
private void RegisterDefaultRules()
{
// Memory pressure rule
RegisterRule(new MemoryPressureRule());
// Data size rule
RegisterRule(new DataSizeRule());
// Concurrency limit rule
RegisterRule(new ConcurrencyLimitRule());
// Performance optimization rule
RegisterRule(new PerformanceOptimizationRule());
}
}
/// <summary>
/// Rule to check memory pressure
/// </summary>
internal class MemoryPressureRule : IPolicyRule
{
public string Name => "MemoryPressure";
public int Priority => 100;
public bool IsEnabled { get; set; } = true;
public Task<RuleResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default)
{
var result = new RuleResult();
if (context.CurrentMemoryPressure > 0.9)
{
result.Passed = false;
result.Violation = new PolicyViolation
{
RuleName = Name,
Description = "Memory pressure too high for operation",
Severity = PolicySeverity.Critical,
Details = new Dictionary<string, object>
{
["CurrentPressure"] = context.CurrentMemoryPressure,
["Threshold"] = 0.9
}
};
}
else if (context.CurrentMemoryPressure > 0.7)
{
result.Actions.Add(new PolicyAction
{
ActionType = "SwitchToExternal",
Priority = 90,
Parameters = new Dictionary<string, object>
{
["Reason"] = "High memory pressure"
}
});
}
result.Recommendations["PreferredAlgorithm"] =
context.CurrentMemoryPressure > 0.5 ? "External" : "InMemory";
return Task.FromResult(result);
}
}
/// <summary>
/// Rule to check data size limits
/// </summary>
internal class DataSizeRule : IPolicyRule
{
public string Name => "DataSize";
public int Priority => 90;
public bool IsEnabled { get; set; } = true;
private const long MaxInMemorySize = 1_073_741_824; // 1 GB
public Task<RuleResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default)
{
var result = new RuleResult();
if (context.DataSize > MaxInMemorySize)
{
result.Actions.Add(new PolicyAction
{
ActionType = "UseExternalAlgorithm",
Priority = 80,
Parameters = new Dictionary<string, object>
{
["DataSize"] = context.DataSize,
["MaxInMemorySize"] = MaxInMemorySize
}
});
result.Recommendations["BufferSize"] = (int)Math.Sqrt(context.DataSize);
}
if (context.DataSize > MaxInMemorySize * 10)
{
result.Actions.Add(new PolicyAction
{
ActionType = "EnableCheckpointing",
Priority = 70,
Parameters = new Dictionary<string, object>
{
["CheckpointInterval"] = (int)Math.Sqrt(context.DataSize / 1000)
}
});
}
return Task.FromResult(result);
}
}
/// <summary>
/// Rule to enforce concurrency limits
/// </summary>
internal class ConcurrencyLimitRule : IPolicyRule
{
public string Name => "ConcurrencyLimit";
public int Priority => 80;
public bool IsEnabled { get; set; } = true;
public Task<RuleResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default)
{
var result = new RuleResult();
var maxConcurrency = Environment.ProcessorCount * 2;
if (context.ConcurrentOperations >= maxConcurrency)
{
result.Passed = false;
result.Violation = new PolicyViolation
{
RuleName = Name,
Description = "Concurrency limit exceeded",
Severity = PolicySeverity.Warning,
Details = new Dictionary<string, object>
{
["CurrentConcurrency"] = context.ConcurrentOperations,
["MaxConcurrency"] = maxConcurrency
}
};
}
var recommendedConcurrency = Math.Min(
Environment.ProcessorCount,
maxConcurrency - context.ConcurrentOperations);
result.Recommendations["MaxConcurrency"] = recommendedConcurrency;
return Task.FromResult(result);
}
}
/// <summary>
/// Rule for performance optimization recommendations
/// </summary>
internal class PerformanceOptimizationRule : IPolicyRule
{
public string Name => "PerformanceOptimization";
public int Priority => 70;
public bool IsEnabled { get; set; } = true;
public Task<RuleResult> EvaluateAsync(RulePolicyContext context, CancellationToken cancellationToken = default)
{
var result = new RuleResult();
// Recommend parallelism for large data
if (context.DataSize > 10_000_000 && context.ConcurrentOperations < Environment.ProcessorCount)
{
result.Actions.Add(new PolicyAction
{
ActionType = "EnableParallelism",
Priority = 60,
Parameters = new Dictionary<string, object>
{
["DegreeOfParallelism"] = Environment.ProcessorCount
}
});
}
// Recommend caching for repeated operations
if (context.Properties.TryGetValue("OperationFrequency", out var freq) &&
freq is int frequency && frequency > 10)
{
result.Actions.Add(new PolicyAction
{
ActionType = "EnableCaching",
Priority = 50,
Parameters = new Dictionary<string, object>
{
["CacheSize"] = Math.Min(context.DataSize / 10, 104857600) // Max 100MB
}
});
}
// Recommend compression for large external data
if (context.DataSize > 100_000_000)
{
result.Recommendations["EnableCompression"] = true;
result.Recommendations["CompressionLevel"] = 6;
}
return Task.FromResult(result);
}
}

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using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Configuration.Policies;
/// <summary>
/// Simple implementation of IPolicyEngine
/// </summary>
public class SimplePolicyEngine : IPolicyEngine
{
private readonly IRulePolicyEngine _ruleEngine;
public SimplePolicyEngine(IRulePolicyEngine ruleEngine)
{
_ruleEngine = ruleEngine;
}
public async Task<bool> EvaluateAsync(string policyName, PolicyContext context)
{
// Map simple context to rule context
var ruleContext = new RulePolicyContext
{
OperationType = context.OperationType,
DataSize = context.DataSize,
AvailableMemory = context.AvailableMemory,
ConcurrentOperations = context.ConcurrentOperations,
CurrentMemoryPressure = context.AvailableMemory > 0 ? 1.0 - ((double)context.AvailableMemory / (context.DataSize + context.AvailableMemory)) : 0.5
};
var result = await _ruleEngine.EvaluateAsync(ruleContext);
// Return true if the policy allows proceeding
return result.ShouldProceed;
}
public void RegisterPolicy(string name, IPolicy policy)
{
// Create adapter rule
_ruleEngine.RegisterRule(new PolicyAdapterRule(name, policy));
}
private class PolicyAdapterRule : IPolicyRule
{
private readonly IPolicy _policy;
public PolicyAdapterRule(string name, IPolicy policy)
{
Name = name;
_policy = policy;
}
public string Name { get; }
public int Priority => 50;
public bool IsEnabled { get; set; } = true;
public async Task<RuleResult> EvaluateAsync(RulePolicyContext context, System.Threading.CancellationToken cancellationToken = default)
{
// Map rule context back to simple context
var simpleContext = new PolicyContext
{
OperationType = context.OperationType,
DataSize = context.DataSize,
AvailableMemory = context.AvailableMemory,
ConcurrentOperations = context.ConcurrentOperations
};
var passed = await _policy.EvaluateAsync(simpleContext);
return new RuleResult
{
Passed = passed
};
}
}
}

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using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Extensions.Configuration;
namespace SqrtSpace.SpaceTime.Configuration.Providers;
/// <summary>
/// Configuration provider for environment-based SpaceTime settings
/// </summary>
public class SpaceTimeEnvironmentConfigurationProvider : ConfigurationProvider
{
private const string Prefix = "SPACETIME_";
private readonly Dictionary<string, string> _mappings;
public SpaceTimeEnvironmentConfigurationProvider()
{
_mappings = BuildMappings();
}
public override void Load()
{
var data = new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
foreach (var envVar in Environment.GetEnvironmentVariables())
{
if (envVar is System.Collections.DictionaryEntry entry &&
entry.Key is string key &&
key.StartsWith(Prefix, StringComparison.OrdinalIgnoreCase))
{
var configKey = MapEnvironmentVariable(key);
if (!string.IsNullOrEmpty(configKey))
{
data[configKey] = entry.Value?.ToString();
}
}
}
Data = data;
}
private string MapEnvironmentVariable(string envVar)
{
// Remove prefix
var key = envVar.Substring(Prefix.Length);
// Check direct mappings first
if (_mappings.TryGetValue(key, out var mapped))
{
return $"SpaceTime:{mapped}";
}
// Convert underscore-separated to dot notation
var parts = key.Split('_', StringSplitOptions.RemoveEmptyEntries);
if (parts.Length == 0)
return "";
// Convert to PascalCase and join with colons
var configPath = string.Join(":", parts.Select(p => ToPascalCase(p)));
return $"SpaceTime:{configPath}";
}
private string ToPascalCase(string input)
{
if (string.IsNullOrEmpty(input))
return input;
return string.Concat(
input.Split('_')
.Select(word => word.Length > 0
? char.ToUpperInvariant(word[0]) + word.Substring(1).ToLowerInvariant()
: ""));
}
private Dictionary<string, string> BuildMappings()
{
return new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
{
// Memory settings
["MAX_MEMORY"] = "Memory:MaxMemory",
["MEMORY_THRESHOLD"] = "Memory:ExternalAlgorithmThreshold",
["GC_THRESHOLD"] = "Memory:GarbageCollectionThreshold",
["BUFFER_STRATEGY"] = "Memory:BufferSizeStrategy",
// Algorithm settings
["MIN_EXTERNAL_SIZE"] = "Algorithms:MinExternalAlgorithmSize",
["ADAPTIVE_SELECTION"] = "Algorithms:EnableAdaptiveSelection",
["LEARNING_RATE"] = "Algorithms:AdaptiveLearningRate",
// Performance settings
["ENABLE_PARALLEL"] = "Performance:EnableParallelism",
["MAX_PARALLELISM"] = "Performance:MaxDegreeOfParallelism",
["ENABLE_SIMD"] = "Performance:EnableSimd",
// Storage settings
["STORAGE_DIR"] = "Storage:DefaultStorageDirectory",
["MAX_DISK_SPACE"] = "Storage:MaxDiskSpace",
["ENABLE_COMPRESSION"] = "Storage:EnableCompression",
["COMPRESSION_LEVEL"] = "Storage:CompressionLevel",
// Diagnostics settings
["ENABLE_METRICS"] = "Diagnostics:EnablePerformanceCounters",
["SAMPLING_RATE"] = "Diagnostics:SamplingRate",
["LOG_LEVEL"] = "Diagnostics:LogLevel",
// Feature flags
["EXPERIMENTAL"] = "Features:EnableExperimentalFeatures",
["ADAPTIVE_STRUCTURES"] = "Features:EnableAdaptiveDataStructures",
["CHECKPOINTING"] = "Features:EnableCheckpointing"
};
}
}
/// <summary>
/// Configuration source for environment variables
/// </summary>
public class SpaceTimeEnvironmentConfigurationSource : IConfigurationSource
{
public IConfigurationProvider Build(IConfigurationBuilder builder)
{
return new SpaceTimeEnvironmentConfigurationProvider();
}
}
/// <summary>
/// Extension methods for environment configuration
/// </summary>
public static class ConfigurationBuilderExtensions
{
/// <summary>
/// Adds SpaceTime environment variables to the configuration
/// </summary>
public static IConfigurationBuilder AddSpaceTimeEnvironmentVariables(this IConfigurationBuilder builder)
{
return builder.Add(new SpaceTimeEnvironmentConfigurationSource());
}
}
/// <summary>
/// Helper class for runtime environment configuration
/// </summary>
public static class SpaceTimeEnvironment
{
/// <summary>
/// Get or set a SpaceTime configuration value via environment variable
/// </summary>
public static string? GetConfiguration(string key)
{
return Environment.GetEnvironmentVariable($"{Prefix}{key}");
}
/// <summary>
/// Set a SpaceTime configuration value via environment variable
/// </summary>
public static void SetConfiguration(string key, string value)
{
Environment.SetEnvironmentVariable($"{Prefix}{key}", value);
}
/// <summary>
/// Apply environment-based overrides to configuration
/// </summary>
public static void ApplyEnvironmentOverrides(ISpaceTimeConfigurationManager configManager)
{
// Memory overrides
if (long.TryParse(GetConfiguration("MAX_MEMORY"), out var maxMemory))
{
configManager.ApplyOverride("Memory.MaxMemory", maxMemory);
}
if (double.TryParse(GetConfiguration("MEMORY_THRESHOLD"), out var memThreshold))
{
configManager.ApplyOverride("Memory.ExternalAlgorithmThreshold", memThreshold);
}
// Performance overrides
if (bool.TryParse(GetConfiguration("ENABLE_PARALLEL"), out var parallel))
{
configManager.ApplyOverride("Performance.EnableParallelism", parallel);
}
if (int.TryParse(GetConfiguration("MAX_PARALLELISM"), out var maxParallel))
{
configManager.ApplyOverride("Performance.MaxDegreeOfParallelism", maxParallel);
}
// Storage overrides
var storageDir = GetConfiguration("STORAGE_DIR");
if (!string.IsNullOrEmpty(storageDir))
{
configManager.ApplyOverride("Storage.DefaultStorageDirectory", storageDir);
}
// Feature overrides
if (bool.TryParse(GetConfiguration("EXPERIMENTAL"), out var experimental))
{
configManager.ApplyOverride("Features.EnableExperimentalFeatures", experimental);
}
}
private const string Prefix = "SPACETIME_";
}

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using System;
using System.Collections.Generic;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Configuration;
/// <summary>
/// Core configuration for SpaceTime optimizations
/// </summary>
public class SpaceTimeConfiguration
{
/// <summary>
/// Global memory limits and policies
/// </summary>
public MemoryConfiguration Memory { get; set; } = new();
/// <summary>
/// Algorithm selection policies
/// </summary>
public AlgorithmConfiguration Algorithms { get; set; } = new();
/// <summary>
/// Performance and optimization settings
/// </summary>
public PerformanceConfiguration Performance { get; set; } = new();
/// <summary>
/// Storage configuration for external data
/// </summary>
public StorageConfiguration Storage { get; set; } = new();
/// <summary>
/// Monitoring and diagnostics settings
/// </summary>
public DiagnosticsConfiguration Diagnostics { get; set; } = new();
/// <summary>
/// Feature toggles and experimental features
/// </summary>
public FeatureConfiguration Features { get; set; } = new();
}
public class MemoryConfiguration
{
/// <summary>
/// Maximum memory allowed for in-memory operations (bytes)
/// </summary>
public long MaxMemory { get; set; } = 1_073_741_824; // 1 GB default
/// <summary>
/// Memory threshold for switching to external algorithms (percentage)
/// </summary>
public double ExternalAlgorithmThreshold { get; set; } = 0.7; // 70%
/// <summary>
/// Memory threshold for aggressive garbage collection (percentage)
/// </summary>
public double GarbageCollectionThreshold { get; set; } = 0.8; // 80%
/// <summary>
/// Enable automatic memory pressure handling
/// </summary>
public bool EnableMemoryPressureHandling { get; set; } = true;
/// <summary>
/// Buffer size calculation strategy
/// </summary>
public BufferSizeStrategy BufferSizeStrategy { get; set; } = BufferSizeStrategy.Sqrt;
/// <summary>
/// Custom buffer size calculator (if Strategy is Custom)
/// </summary>
public Func<long, int>? CustomBufferSizeCalculator { get; set; }
}
public enum BufferSizeStrategy
{
/// <summary>
/// Use √n buffering (Williams' algorithm)
/// </summary>
Sqrt,
/// <summary>
/// Use fixed buffer sizes
/// </summary>
Fixed,
/// <summary>
/// Use logarithmic buffer sizes
/// </summary>
Logarithmic,
/// <summary>
/// Use custom calculator function
/// </summary>
Custom
}
public class AlgorithmConfiguration
{
/// <summary>
/// Minimum data size to consider external algorithms
/// </summary>
public long MinExternalAlgorithmSize { get; set; } = 10_000_000; // 10 MB
/// <summary>
/// Algorithm selection policies by operation type
/// </summary>
public Dictionary<string, AlgorithmPolicy> Policies { get; set; } = new()
{
["Sort"] = new AlgorithmPolicy
{
PreferExternal = true,
SizeThreshold = 1_000_000,
MaxMemoryFactor = 0.5
},
["Join"] = new AlgorithmPolicy
{
PreferExternal = true,
SizeThreshold = 10_000_000,
MaxMemoryFactor = 0.7
},
["GroupBy"] = new AlgorithmPolicy
{
PreferExternal = false,
SizeThreshold = 5_000_000,
MaxMemoryFactor = 0.6
}
};
/// <summary>
/// Enable adaptive algorithm selection based on runtime metrics
/// </summary>
public bool EnableAdaptiveSelection { get; set; } = true;
/// <summary>
/// Learning rate for adaptive algorithm selection
/// </summary>
public double AdaptiveLearningRate { get; set; } = 0.1;
}
public class AlgorithmPolicy
{
/// <summary>
/// Prefer external algorithms when possible
/// </summary>
public bool PreferExternal { get; set; }
/// <summary>
/// Size threshold for switching algorithms
/// </summary>
public long SizeThreshold { get; set; }
/// <summary>
/// Maximum memory usage as factor of available memory
/// </summary>
public double MaxMemoryFactor { get; set; }
/// <summary>
/// Custom selection function
/// </summary>
public Func<AlgorithmContext, AlgorithmChoice>? CustomSelector { get; set; }
}
public class AlgorithmContext
{
public string OperationType { get; set; } = "";
public long DataSize { get; set; }
public long AvailableMemory { get; set; }
public double CurrentMemoryPressure { get; set; }
public Dictionary<string, object> Metadata { get; set; } = new();
}
public enum AlgorithmChoice
{
InMemory,
External,
Hybrid
}
public class PerformanceConfiguration
{
/// <summary>
/// Enable parallel processing where applicable
/// </summary>
public bool EnableParallelism { get; set; } = true;
/// <summary>
/// Maximum degree of parallelism (-1 for unlimited)
/// </summary>
public int MaxDegreeOfParallelism { get; set; } = Environment.ProcessorCount;
/// <summary>
/// Chunk size for parallel operations
/// </summary>
public int ParallelChunkSize { get; set; } = 1000;
/// <summary>
/// Enable CPU cache optimization
/// </summary>
public bool EnableCacheOptimization { get; set; } = true;
/// <summary>
/// Cache line size (bytes)
/// </summary>
public int CacheLineSize { get; set; } = 64;
/// <summary>
/// Enable SIMD optimizations where available
/// </summary>
public bool EnableSimd { get; set; } = true;
/// <summary>
/// Prefetch distance for sequential operations
/// </summary>
public int PrefetchDistance { get; set; } = 8;
}
public class StorageConfiguration
{
/// <summary>
/// Default directory for external storage
/// </summary>
public string DefaultStorageDirectory { get; set; } = Path.Combine(Path.GetTempPath(), "spacetime");
/// <summary>
/// Maximum disk space allowed for external storage (bytes)
/// </summary>
public long MaxDiskSpace { get; set; } = 10_737_418_240; // 10 GB
/// <summary>
/// File allocation unit size
/// </summary>
public int AllocationUnitSize { get; set; } = 4096;
/// <summary>
/// Enable compression for external storage
/// </summary>
public bool EnableCompression { get; set; } = true;
/// <summary>
/// Compression level (1-9)
/// </summary>
public int CompressionLevel { get; set; } = 6;
/// <summary>
/// Cleanup policy for temporary files
/// </summary>
public CleanupPolicy CleanupPolicy { get; set; } = CleanupPolicy.OnDispose;
/// <summary>
/// File retention period for debugging
/// </summary>
public TimeSpan RetentionPeriod { get; set; } = TimeSpan.FromHours(1);
}
public enum CleanupPolicy
{
/// <summary>
/// Clean up immediately when disposed
/// </summary>
OnDispose,
/// <summary>
/// Clean up after retention period
/// </summary>
AfterRetention,
/// <summary>
/// Never clean up automatically
/// </summary>
Manual
}
public class DiagnosticsConfiguration
{
/// <summary>
/// Enable performance counters
/// </summary>
public bool EnablePerformanceCounters { get; set; } = true;
/// <summary>
/// Enable memory tracking
/// </summary>
public bool EnableMemoryTracking { get; set; } = true;
/// <summary>
/// Enable operation timing
/// </summary>
public bool EnableOperationTiming { get; set; } = true;
/// <summary>
/// Sampling rate for detailed metrics (0.0-1.0)
/// </summary>
public double SamplingRate { get; set; } = 0.1;
/// <summary>
/// Enable OpenTelemetry integration
/// </summary>
public bool EnableOpenTelemetry { get; set; } = true;
/// <summary>
/// Custom metric exporters
/// </summary>
public List<string> MetricExporters { get; set; } = new() { "console", "otlp" };
/// <summary>
/// Diagnostic log level
/// </summary>
public DiagnosticLevel LogLevel { get; set; } = DiagnosticLevel.Warning;
}
public enum DiagnosticLevel
{
None,
Error,
Warning,
Information,
Debug,
Trace
}
public class FeatureConfiguration
{
/// <summary>
/// Enable experimental features
/// </summary>
public bool EnableExperimentalFeatures { get; set; } = false;
/// <summary>
/// Enable adaptive data structures
/// </summary>
public bool EnableAdaptiveDataStructures { get; set; } = true;
/// <summary>
/// Enable checkpointing for long operations
/// </summary>
public bool EnableCheckpointing { get; set; } = true;
/// <summary>
/// Enable predictive memory allocation
/// </summary>
public bool EnablePredictiveAllocation { get; set; } = false;
/// <summary>
/// Enable machine learning optimizations
/// </summary>
public bool EnableMachineLearningOptimizations { get; set; } = false;
/// <summary>
/// Feature-specific settings
/// </summary>
public Dictionary<string, object> FeatureSettings { get; set; } = new();
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Configuration and policy management for SpaceTime optimizations</Description>
<PackageTags>configuration;policy;settings;rules;spacetime</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Configuration</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Options" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.7" />
<PackageReference Include="FluentValidation" Version="12.0.0" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System;
using FluentValidation;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using SqrtSpace.SpaceTime.Configuration.Policies;
namespace SqrtSpace.SpaceTime.Configuration.Validation;
/// <summary>
/// Validator for SpaceTime configuration
/// </summary>
public class SpaceTimeConfigurationValidator : AbstractValidator<SpaceTimeConfiguration>
{
public SpaceTimeConfigurationValidator()
{
RuleFor(x => x.Memory)
.NotNull()
.SetValidator(new MemoryConfigurationValidator());
RuleFor(x => x.Algorithms)
.NotNull()
.SetValidator(new AlgorithmConfigurationValidator());
RuleFor(x => x.Performance)
.NotNull()
.SetValidator(new PerformanceConfigurationValidator());
RuleFor(x => x.Storage)
.NotNull()
.SetValidator(new StorageConfigurationValidator());
RuleFor(x => x.Diagnostics)
.NotNull()
.SetValidator(new DiagnosticsConfigurationValidator());
RuleFor(x => x.Features)
.NotNull()
.SetValidator(new FeatureConfigurationValidator());
}
}
public class MemoryConfigurationValidator : AbstractValidator<MemoryConfiguration>
{
public MemoryConfigurationValidator()
{
RuleFor(x => x.MaxMemory)
.GreaterThan(0)
.WithMessage("MaxMemory must be greater than 0");
RuleFor(x => x.ExternalAlgorithmThreshold)
.InclusiveBetween(0.1, 1.0)
.WithMessage("ExternalAlgorithmThreshold must be between 0.1 and 1.0");
RuleFor(x => x.GarbageCollectionThreshold)
.InclusiveBetween(0.1, 1.0)
.WithMessage("GarbageCollectionThreshold must be between 0.1 and 1.0");
RuleFor(x => x.GarbageCollectionThreshold)
.GreaterThan(x => x.ExternalAlgorithmThreshold)
.WithMessage("GarbageCollectionThreshold should be greater than ExternalAlgorithmThreshold");
When(x => x.BufferSizeStrategy == BufferSizeStrategy.Custom, () =>
{
RuleFor(x => x.CustomBufferSizeCalculator)
.NotNull()
.WithMessage("CustomBufferSizeCalculator is required when BufferSizeStrategy is Custom");
});
}
}
public class AlgorithmConfigurationValidator : AbstractValidator<AlgorithmConfiguration>
{
public AlgorithmConfigurationValidator()
{
RuleFor(x => x.MinExternalAlgorithmSize)
.GreaterThan(0)
.WithMessage("MinExternalAlgorithmSize must be greater than 0");
RuleFor(x => x.Policies)
.NotNull()
.WithMessage("Policies cannot be null");
RuleForEach(x => x.Policies.Values)
.SetValidator(new AlgorithmPolicyValidator());
When(x => x.EnableAdaptiveSelection, () =>
{
RuleFor(x => x.AdaptiveLearningRate)
.InclusiveBetween(0.01, 1.0)
.WithMessage("AdaptiveLearningRate must be between 0.01 and 1.0");
});
}
}
public class AlgorithmPolicyValidator : AbstractValidator<AlgorithmPolicy>
{
public AlgorithmPolicyValidator()
{
RuleFor(x => x.SizeThreshold)
.GreaterThan(0)
.WithMessage("SizeThreshold must be greater than 0");
RuleFor(x => x.MaxMemoryFactor)
.InclusiveBetween(0.1, 1.0)
.WithMessage("MaxMemoryFactor must be between 0.1 and 1.0");
}
}
public class PerformanceConfigurationValidator : AbstractValidator<PerformanceConfiguration>
{
public PerformanceConfigurationValidator()
{
When(x => x.EnableParallelism, () =>
{
RuleFor(x => x.MaxDegreeOfParallelism)
.Must(x => x == -1 || x > 0)
.WithMessage("MaxDegreeOfParallelism must be -1 (unlimited) or greater than 0");
RuleFor(x => x.ParallelChunkSize)
.GreaterThan(0)
.WithMessage("ParallelChunkSize must be greater than 0");
});
RuleFor(x => x.CacheLineSize)
.Must(x => x > 0 && (x & (x - 1)) == 0) // Must be power of 2
.WithMessage("CacheLineSize must be a power of 2");
RuleFor(x => x.PrefetchDistance)
.GreaterThan(0)
.WithMessage("PrefetchDistance must be greater than 0");
}
}
public class StorageConfigurationValidator : AbstractValidator<StorageConfiguration>
{
public StorageConfigurationValidator()
{
RuleFor(x => x.DefaultStorageDirectory)
.NotEmpty()
.WithMessage("DefaultStorageDirectory cannot be empty");
RuleFor(x => x.MaxDiskSpace)
.GreaterThan(0)
.WithMessage("MaxDiskSpace must be greater than 0");
RuleFor(x => x.AllocationUnitSize)
.GreaterThan(0)
.Must(x => x % 512 == 0) // Must be multiple of 512
.WithMessage("AllocationUnitSize must be a multiple of 512");
When(x => x.EnableCompression, () =>
{
RuleFor(x => x.CompressionLevel)
.InclusiveBetween(1, 9)
.WithMessage("CompressionLevel must be between 1 and 9");
});
RuleFor(x => x.RetentionPeriod)
.GreaterThan(TimeSpan.Zero)
.WithMessage("RetentionPeriod must be greater than zero");
}
}
public class DiagnosticsConfigurationValidator : AbstractValidator<DiagnosticsConfiguration>
{
public DiagnosticsConfigurationValidator()
{
RuleFor(x => x.SamplingRate)
.InclusiveBetween(0.0, 1.0)
.WithMessage("SamplingRate must be between 0.0 and 1.0");
RuleFor(x => x.MetricExporters)
.NotNull()
.WithMessage("MetricExporters cannot be null");
}
}
public class FeatureConfigurationValidator : AbstractValidator<FeatureConfiguration>
{
public FeatureConfigurationValidator()
{
RuleFor(x => x.FeatureSettings)
.NotNull()
.WithMessage("FeatureSettings cannot be null");
}
}
/// <summary>
/// Options validator for dependency injection
/// </summary>
public class SpaceTimeConfigurationOptionsValidator : IValidateOptions<SpaceTimeConfiguration>
{
private readonly SpaceTimeConfigurationValidator _validator;
public SpaceTimeConfigurationOptionsValidator()
{
_validator = new SpaceTimeConfigurationValidator();
}
public ValidateOptionsResult Validate(string? name, SpaceTimeConfiguration options)
{
var result = _validator.Validate(options);
if (result.IsValid)
{
return ValidateOptionsResult.Success;
}
var errors = string.Join("; ", result.Errors.Select(e => e.ErrorMessage));
return ValidateOptionsResult.Fail(errors);
}
}
/// <summary>
/// Extension methods for configuration validation
/// </summary>
public static class ServiceCollectionExtensions
{
public static IServiceCollection AddSpaceTimeConfiguration(
this IServiceCollection services,
Microsoft.Extensions.Configuration.IConfiguration configuration)
{
// Configure options
services.Configure<SpaceTimeConfiguration>(configuration.GetSection("SpaceTime"));
// Add validation
services.AddSingleton<IValidateOptions<SpaceTimeConfiguration>, SpaceTimeConfigurationOptionsValidator>();
// Add configuration manager
services.AddSingleton<ISpaceTimeConfigurationManager, SpaceTimeConfigurationManager>();
services.AddHostedService(provider => provider.GetRequiredService<ISpaceTimeConfigurationManager>() as SpaceTimeConfigurationManager);
// Add policy engines
services.AddSingleton<IRulePolicyEngine, PolicyEngine>();
services.AddSingleton<IPolicyEngine, SimplePolicyEngine>();
return services;
}
}

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using System.Text.Json;
namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Manages checkpointing for fault-tolerant operations
/// </summary>
public class CheckpointManager : IDisposable
{
private readonly string _checkpointDirectory;
private readonly CheckpointStrategy _strategy;
private readonly int _checkpointInterval;
private int _operationCount;
private readonly List<string> _checkpointFiles = new();
/// <summary>
/// Initializes a new checkpoint manager
/// </summary>
/// <param name="checkpointDirectory">Directory to store checkpoints</param>
/// <param name="strategy">Checkpointing strategy</param>
/// <param name="totalOperations">Total expected operations (for √n calculation)</param>
public CheckpointManager(
string? checkpointDirectory = null,
CheckpointStrategy strategy = CheckpointStrategy.SqrtN,
long totalOperations = 1_000_000)
{
_checkpointDirectory = checkpointDirectory ?? Path.Combine(Path.GetTempPath(), $"spacetime_checkpoint_{Guid.NewGuid()}");
_strategy = strategy;
_checkpointInterval = SpaceTimeCalculator.CalculateCheckpointCount(totalOperations, strategy);
Directory.CreateDirectory(_checkpointDirectory);
}
/// <summary>
/// Checks if a checkpoint should be created
/// </summary>
/// <returns>True if checkpoint should be created</returns>
public bool ShouldCheckpoint()
{
_operationCount++;
return _strategy switch
{
CheckpointStrategy.None => false,
CheckpointStrategy.SqrtN => _operationCount % _checkpointInterval == 0,
CheckpointStrategy.Linear => _operationCount % 1000 == 0,
CheckpointStrategy.Logarithmic => IsPowerOfTwo(_operationCount),
_ => false
};
}
/// <summary>
/// Creates a checkpoint for the given state
/// </summary>
/// <typeparam name="T">Type of state to checkpoint</typeparam>
/// <param name="state">State to save</param>
/// <param name="checkpointId">Optional checkpoint ID</param>
/// <returns>Path to checkpoint file</returns>
public async Task<string> CreateCheckpointAsync<T>(T state, string? checkpointId = null)
{
checkpointId ??= $"checkpoint_{_operationCount}_{DateTime.UtcNow.Ticks}";
var filePath = Path.Combine(_checkpointDirectory, $"{checkpointId}.json");
var json = JsonSerializer.Serialize(state, new JsonSerializerOptions
{
WriteIndented = true,
PropertyNamingPolicy = JsonNamingPolicy.CamelCase
});
await File.WriteAllTextAsync(filePath, json);
_checkpointFiles.Add(filePath);
// Clean up old checkpoints if using √n strategy
if (_strategy == CheckpointStrategy.SqrtN && _checkpointFiles.Count > Math.Sqrt(_operationCount))
{
CleanupOldCheckpoints();
}
return filePath;
}
/// <summary>
/// Restores state from the latest checkpoint
/// </summary>
/// <typeparam name="T">Type of state to restore</typeparam>
/// <returns>Restored state or null if no checkpoint exists</returns>
public async Task<T?> RestoreLatestCheckpointAsync<T>()
{
var latestCheckpoint = Directory.GetFiles(_checkpointDirectory, "*.json")
.OrderByDescending(f => new FileInfo(f).LastWriteTimeUtc)
.FirstOrDefault();
if (latestCheckpoint == null)
return default;
var json = await File.ReadAllTextAsync(latestCheckpoint);
return JsonSerializer.Deserialize<T>(json, new JsonSerializerOptions
{
PropertyNamingPolicy = JsonNamingPolicy.CamelCase
});
}
/// <summary>
/// Restores state from a specific checkpoint
/// </summary>
/// <typeparam name="T">Type of state to restore</typeparam>
/// <param name="checkpointId">Checkpoint ID to restore</param>
/// <returns>Restored state or null if checkpoint doesn't exist</returns>
public async Task<T?> RestoreCheckpointAsync<T>(string checkpointId)
{
var filePath = Path.Combine(_checkpointDirectory, $"{checkpointId}.json");
if (!File.Exists(filePath))
return default;
var json = await File.ReadAllTextAsync(filePath);
return JsonSerializer.Deserialize<T>(json, new JsonSerializerOptions
{
PropertyNamingPolicy = JsonNamingPolicy.CamelCase
});
}
/// <summary>
/// Gets the number of operations since last checkpoint
/// </summary>
public int OperationsSinceLastCheckpoint => _operationCount % _checkpointInterval;
/// <summary>
/// Saves state for a specific checkpoint and key
/// </summary>
/// <typeparam name="T">Type of state to save</typeparam>
/// <param name="checkpointId">Checkpoint ID</param>
/// <param name="key">State key</param>
/// <param name="state">State to save</param>
/// <param name="cancellationToken">Cancellation token</param>
public async Task SaveStateAsync<T>(string checkpointId, string key, T state, CancellationToken cancellationToken = default) where T : class
{
var filePath = Path.Combine(_checkpointDirectory, $"{checkpointId}_{key}.json");
var json = JsonSerializer.Serialize(state, new JsonSerializerOptions
{
WriteIndented = true,
PropertyNamingPolicy = JsonNamingPolicy.CamelCase
});
await File.WriteAllTextAsync(filePath, json, cancellationToken);
}
/// <summary>
/// Loads state for a specific checkpoint and key
/// </summary>
/// <typeparam name="T">Type of state to load</typeparam>
/// <param name="checkpointId">Checkpoint ID</param>
/// <param name="key">State key</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Loaded state or null if not found</returns>
public async Task<T?> LoadStateAsync<T>(string checkpointId, string key, CancellationToken cancellationToken = default) where T : class
{
var filePath = Path.Combine(_checkpointDirectory, $"{checkpointId}_{key}.json");
if (!File.Exists(filePath))
return null;
var json = await File.ReadAllTextAsync(filePath, cancellationToken);
return JsonSerializer.Deserialize<T>(json, new JsonSerializerOptions
{
PropertyNamingPolicy = JsonNamingPolicy.CamelCase
});
}
/// <summary>
/// Cleans up checkpoint files
/// </summary>
public void Dispose()
{
try
{
if (Directory.Exists(_checkpointDirectory))
{
Directory.Delete(_checkpointDirectory, recursive: true);
}
}
catch
{
// Best effort cleanup
}
}
private void CleanupOldCheckpoints()
{
// Keep only the most recent √n checkpoints
var toKeep = (int)Math.Sqrt(_operationCount);
var toDelete = _checkpointFiles
.OrderBy(f => new FileInfo(f).LastWriteTimeUtc)
.Take(_checkpointFiles.Count - toKeep)
.ToList();
foreach (var file in toDelete)
{
try
{
File.Delete(file);
_checkpointFiles.Remove(file);
}
catch
{
// Best effort
}
}
}
private static bool IsPowerOfTwo(int n)
{
return n > 0 && (n & (n - 1)) == 0;
}
}
/// <summary>
/// Attribute to mark methods as checkpointable
/// </summary>
[AttributeUsage(AttributeTargets.Method)]
public class CheckpointableAttribute : Attribute
{
/// <summary>
/// Checkpointing strategy to use
/// </summary>
public CheckpointStrategy Strategy { get; set; } = CheckpointStrategy.SqrtN;
/// <summary>
/// Whether to automatically restore from checkpoint on failure
/// </summary>
public bool AutoRestore { get; set; } = true;
/// <summary>
/// Custom checkpoint directory
/// </summary>
public string? CheckpointDirectory { get; set; }
}

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namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Memory optimization strategy
/// </summary>
public enum MemoryStrategy
{
/// <summary>
/// Use O(n) memory for best performance
/// </summary>
Full,
/// <summary>
/// Use O(√n) memory with space-time tradeoffs
/// </summary>
SqrtN,
/// <summary>
/// Use O(log n) memory with significant performance tradeoffs
/// </summary>
Logarithmic,
/// <summary>
/// Automatically choose based on available memory
/// </summary>
Adaptive
}
/// <summary>
/// Cache item priority levels
/// </summary>
public enum CacheItemPriority
{
Low = 0,
Normal = 1,
High = 2,
NeverRemove = 3
}

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namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Provides external storage for algorithms that exceed memory limits
/// </summary>
public class ExternalStorage<T> : IDisposable
{
private readonly string _tempDirectory;
private readonly List<string> _spillFiles = new();
private readonly ISerializer<T> _serializer;
private int _spillFileCounter;
/// <summary>
/// Initializes external storage
/// </summary>
/// <param name="tempDirectory">Directory for temporary files</param>
/// <param name="serializer">Custom serializer (optional)</param>
public ExternalStorage(string? tempDirectory = null, ISerializer<T>? serializer = null)
{
_tempDirectory = tempDirectory ?? Path.Combine(Path.GetTempPath(), $"spacetime_external_{Guid.NewGuid()}");
_serializer = serializer ?? new JsonSerializer<T>();
Directory.CreateDirectory(_tempDirectory);
}
/// <summary>
/// Spills data to disk
/// </summary>
/// <param name="data">Data to spill</param>
/// <returns>Path to spill file</returns>
public async Task<string> SpillToDiskAsync(IEnumerable<T> data)
{
var spillFile = Path.Combine(_tempDirectory, $"spill_{_spillFileCounter++}.dat");
_spillFiles.Add(spillFile);
await using var stream = new FileStream(spillFile, FileMode.Create, FileAccess.Write, FileShare.None, 4096, useAsync: true);
await _serializer.SerializeAsync(stream, data);
return spillFile;
}
/// <summary>
/// Reads spilled data from disk
/// </summary>
/// <param name="spillFile">Path to spill file</param>
/// <returns>Data from spill file</returns>
public async IAsyncEnumerable<T> ReadFromDiskAsync(string spillFile)
{
await using var stream = new FileStream(spillFile, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, useAsync: true);
await foreach (var item in _serializer.DeserializeAsync(stream))
{
yield return item;
}
}
/// <summary>
/// Merges multiple spill files
/// </summary>
/// <param name="comparer">Comparer for merge operation</param>
/// <returns>Merged data stream</returns>
public async IAsyncEnumerable<T> MergeSpillFilesAsync(IComparer<T> comparer)
{
var streams = new List<IAsyncEnumerator<T>>();
var heap = new SortedDictionary<T, int>(comparer);
try
{
// Initialize streams
for (int i = 0; i < _spillFiles.Count; i++)
{
var enumerator = ReadFromDiskAsync(_spillFiles[i]).GetAsyncEnumerator();
streams.Add(enumerator);
if (await enumerator.MoveNextAsync())
{
heap[enumerator.Current] = i;
}
}
// Merge using heap
while (heap.Count > 0)
{
var min = heap.First();
yield return min.Key;
heap.Remove(min.Key);
var streamIndex = min.Value;
if (await streams[streamIndex].MoveNextAsync())
{
heap[streams[streamIndex].Current] = streamIndex;
}
}
}
finally
{
// Dispose all streams
foreach (var stream in streams)
{
await stream.DisposeAsync();
}
}
}
/// <summary>
/// Gets total size of spilled data
/// </summary>
public long GetSpillSize()
{
return _spillFiles.Sum(f => new FileInfo(f).Length);
}
/// <summary>
/// Writes a single item to external storage
/// </summary>
/// <param name="key">Key for the item</param>
/// <param name="item">Item to store</param>
public async Task WriteAsync(string key, T item)
{
var filePath = Path.Combine(_tempDirectory, $"{key}.dat");
await using var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None, 4096, useAsync: true);
await _serializer.SerializeAsync(stream, new[] { item });
}
/// <summary>
/// Reads a single item from external storage
/// </summary>
/// <param name="key">Key for the item</param>
/// <returns>The stored item or default if not found</returns>
public async Task<T?> ReadAsync(string key)
{
var filePath = Path.Combine(_tempDirectory, $"{key}.dat");
if (!File.Exists(filePath))
return default;
await using var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, useAsync: true);
await foreach (var item in _serializer.DeserializeAsync(stream))
{
return item; // Return first item
}
return default;
}
/// <summary>
/// Cleans up temporary files
/// </summary>
public void Dispose()
{
foreach (var file in _spillFiles)
{
try
{
File.Delete(file);
}
catch
{
// Best effort
}
}
try
{
if (Directory.Exists(_tempDirectory))
{
Directory.Delete(_tempDirectory, recursive: true);
}
}
catch
{
// Best effort
}
}
}
/// <summary>
/// Interface for serializing data to external storage
/// </summary>
public interface ISerializer<T>
{
/// <summary>Serializes data to stream</summary>
Task SerializeAsync(Stream stream, IEnumerable<T> data);
/// <summary>Deserializes data from stream</summary>
IAsyncEnumerable<T> DeserializeAsync(Stream stream);
}
/// <summary>
/// Default JSON serializer implementation
/// </summary>
internal class JsonSerializer<T> : ISerializer<T>
{
public async Task SerializeAsync(Stream stream, IEnumerable<T> data)
{
await using var writer = new StreamWriter(stream);
foreach (var item in data)
{
var json = System.Text.Json.JsonSerializer.Serialize(item);
await writer.WriteLineAsync(json);
}
}
public async IAsyncEnumerable<T> DeserializeAsync(Stream stream)
{
using var reader = new StreamReader(stream);
string? line;
while ((line = await reader.ReadLineAsync()) != null)
{
var item = System.Text.Json.JsonSerializer.Deserialize<T>(line);
if (item != null)
yield return item;
}
}
}

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namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Interface for objects that support checkpointing
/// </summary>
public interface ICheckpointable
{
/// <summary>
/// Gets the checkpoint identifier for this object
/// </summary>
string GetCheckpointId();
/// <summary>
/// Restores the object state from a checkpoint
/// </summary>
/// <param name="state">The checkpoint state to restore from</param>
void RestoreFromCheckpoint(object state);
}

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using System.Runtime.InteropServices;
namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Models the memory hierarchy of the system for optimization decisions
/// </summary>
public class MemoryHierarchy
{
/// <summary>L1 cache size in bytes</summary>
public long L1CacheSize { get; init; }
/// <summary>L2 cache size in bytes</summary>
public long L2CacheSize { get; init; }
/// <summary>L3 cache size in bytes</summary>
public long L3CacheSize { get; init; }
/// <summary>RAM size in bytes</summary>
public long RamSize { get; init; }
/// <summary>L1 cache latency in nanoseconds</summary>
public double L1LatencyNs { get; init; }
/// <summary>L2 cache latency in nanoseconds</summary>
public double L2LatencyNs { get; init; }
/// <summary>L3 cache latency in nanoseconds</summary>
public double L3LatencyNs { get; init; }
/// <summary>RAM latency in nanoseconds</summary>
public double RamLatencyNs { get; init; }
/// <summary>SSD latency in nanoseconds</summary>
public double SsdLatencyNs { get; init; }
/// <summary>
/// Detects the current system's memory hierarchy
/// </summary>
/// <returns>Memory hierarchy for the current system</returns>
public static MemoryHierarchy DetectSystem()
{
// These are typical values for modern systems
// In a production implementation, these would be detected from the system
return new MemoryHierarchy
{
L1CacheSize = 32 * 1024, // 32 KB
L2CacheSize = 256 * 1024, // 256 KB
L3CacheSize = 8 * 1024 * 1024, // 8 MB
RamSize = GetTotalPhysicalMemory(),
L1LatencyNs = 1,
L2LatencyNs = 3,
L3LatencyNs = 12,
RamLatencyNs = 100,
SsdLatencyNs = 10_000
};
}
/// <summary>
/// Determines which memory level can hold the given data size
/// </summary>
/// <param name="dataSize">Size of data in bytes</param>
/// <returns>The memory level that can hold the data</returns>
public MemoryLevel GetOptimalLevel(long dataSize)
{
if (dataSize <= L1CacheSize)
return MemoryLevel.L1Cache;
if (dataSize <= L2CacheSize)
return MemoryLevel.L2Cache;
if (dataSize <= L3CacheSize)
return MemoryLevel.L3Cache;
if (dataSize <= RamSize)
return MemoryLevel.Ram;
return MemoryLevel.Disk;
}
/// <summary>
/// Estimates access latency for the given data size
/// </summary>
/// <param name="dataSize">Size of data in bytes</param>
/// <returns>Estimated latency in nanoseconds</returns>
public double EstimateLatency(long dataSize)
{
return GetOptimalLevel(dataSize) switch
{
MemoryLevel.L1Cache => L1LatencyNs,
MemoryLevel.L2Cache => L2LatencyNs,
MemoryLevel.L3Cache => L3LatencyNs,
MemoryLevel.Ram => RamLatencyNs,
MemoryLevel.Disk => SsdLatencyNs,
_ => SsdLatencyNs
};
}
private static long GetTotalPhysicalMemory()
{
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
// On Windows, use GC.GetTotalMemory as approximation
return GC.GetTotalMemory(false) * 10; // Rough estimate
}
else
{
// On Unix-like systems, try to read from /proc/meminfo
try
{
if (File.Exists("/proc/meminfo"))
{
var lines = File.ReadAllLines("/proc/meminfo");
var memLine = lines.FirstOrDefault(l => l.StartsWith("MemTotal:"));
if (memLine != null)
{
var parts = memLine.Split(' ', StringSplitOptions.RemoveEmptyEntries);
if (parts.Length >= 2 && long.TryParse(parts[1], out var kb))
{
return kb * 1024; // Convert KB to bytes
}
}
}
}
catch
{
// Fallback if reading fails
}
}
// Default fallback: 8GB
return 8L * 1024 * 1024 * 1024;
}
}
/// <summary>
/// Memory hierarchy levels
/// </summary>
public enum MemoryLevel
{
/// <summary>L1 CPU cache</summary>
L1Cache,
/// <summary>L2 CPU cache</summary>
L2Cache,
/// <summary>L3 CPU cache</summary>
L3Cache,
/// <summary>Main memory (RAM)</summary>
Ram,
/// <summary>Disk storage (SSD/HDD)</summary>
Disk
}

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namespace SqrtSpace.SpaceTime.Core;
/// <summary>
/// Core calculations for space-time tradeoffs based on Williams' theoretical bounds
/// </summary>
public static class SpaceTimeCalculator
{
/// <summary>
/// Calculates the optimal √n interval for a given data size
/// </summary>
/// <param name="dataSize">Total number of elements</param>
/// <param name="elementSize">Size of each element in bytes</param>
/// <returns>Optimal interval size</returns>
public static int CalculateSqrtInterval(long dataSize, int elementSize = 8)
{
if (dataSize <= 0)
throw new ArgumentOutOfRangeException(nameof(dataSize), "Data size must be positive");
var sqrtN = (int)Math.Sqrt(dataSize);
// Align to cache line boundaries for better performance
const int cacheLineSize = 64;
var elementsPerCacheLine = cacheLineSize / elementSize;
if (sqrtN > elementsPerCacheLine)
{
sqrtN = (sqrtN / elementsPerCacheLine) * elementsPerCacheLine;
}
return Math.Max(1, sqrtN);
}
/// <summary>
/// Calculates optimal buffer size for external algorithms
/// </summary>
/// <param name="totalDataSize">Total data size in bytes</param>
/// <param name="availableMemory">Available memory in bytes</param>
/// <returns>Optimal buffer size in bytes</returns>
public static long CalculateOptimalBufferSize(long totalDataSize, long availableMemory)
{
// Use √n of total data or available memory, whichever is smaller
var sqrtSize = (long)Math.Sqrt(totalDataSize);
return Math.Min(sqrtSize, availableMemory);
}
/// <summary>
/// Calculates the number of checkpoints needed for fault tolerance
/// </summary>
/// <param name="totalOperations">Total number of operations</param>
/// <param name="strategy">Checkpointing strategy</param>
/// <returns>Number of checkpoints</returns>
public static int CalculateCheckpointCount(long totalOperations, CheckpointStrategy strategy = CheckpointStrategy.SqrtN)
{
return strategy switch
{
CheckpointStrategy.SqrtN => (int)Math.Sqrt(totalOperations),
CheckpointStrategy.Linear => (int)(totalOperations / 1000), // Every 1000 operations
CheckpointStrategy.Logarithmic => (int)Math.Log2(totalOperations),
CheckpointStrategy.None => 0,
_ => throw new ArgumentOutOfRangeException(nameof(strategy))
};
}
/// <summary>
/// Estimates memory savings using √n strategy
/// </summary>
/// <param name="standardMemoryUsage">Memory usage with standard approach</param>
/// <param name="dataSize">Number of elements</param>
/// <returns>Estimated memory savings percentage</returns>
public static double EstimateMemorySavings(long standardMemoryUsage, long dataSize)
{
if (dataSize <= 0 || standardMemoryUsage <= 0)
return 0;
var sqrtMemoryUsage = standardMemoryUsage / Math.Sqrt(dataSize);
return (1 - sqrtMemoryUsage / standardMemoryUsage) * 100;
}
/// <summary>
/// Calculates optimal block size for cache-efficient operations
/// </summary>
/// <param name="matrixSize">Size of matrix (assuming square)</param>
/// <param name="cacheSize">L3 cache size in bytes</param>
/// <param name="elementSize">Size of each element in bytes</param>
/// <returns>Optimal block size</returns>
public static int CalculateCacheBlockSize(int matrixSize, long cacheSize, int elementSize = 8)
{
// Three blocks should fit in cache (for matrix multiplication)
var blockElements = (long)Math.Sqrt(cacheSize / (3 * elementSize));
var blockSize = (int)Math.Min(blockElements, matrixSize);
// Ensure block size is a divisor of matrix size when possible
while (blockSize > 1 && matrixSize % blockSize != 0)
{
blockSize--;
}
return Math.Max(1, blockSize);
}
/// <summary>
/// Calculates optimal space complexity for a given time complexity
/// </summary>
/// <param name="dataSize">Size of the data</param>
/// <param name="timeExponent">Exponent of the time complexity (e.g., 2.0 for O(n^2))</param>
/// <returns>Optimal space usage</returns>
public static int CalculateSpaceForTimeComplexity(long dataSize, double timeExponent)
{
if (dataSize <= 0)
throw new ArgumentOutOfRangeException(nameof(dataSize), "Data size must be positive");
if (timeExponent <= 0)
throw new ArgumentOutOfRangeException(nameof(timeExponent), "Time exponent must be positive");
// For time complexity O(n^k), optimal space is O(n^(1/k))
// This follows from the space-time tradeoff principle
var spaceExponent = 1.0 / timeExponent;
var optimalSpace = Math.Pow(dataSize, spaceExponent);
return Math.Max(1, (int)Math.Round(optimalSpace));
}
/// <summary>
/// Estimates the overhead of using external storage
/// </summary>
/// <param name="dataSize">Total data size</param>
/// <param name="blockSize">Block size for external operations</param>
/// <returns>Estimated overhead percentage</returns>
public static double EstimateExternalStorageOverhead(long dataSize, int blockSize)
{
if (dataSize <= 0 || blockSize <= 0)
return 0;
// Calculate number of I/O operations
var numBlocks = (dataSize + blockSize - 1) / blockSize;
// Estimate overhead based on number of I/O operations
// Each I/O operation has a fixed cost
const double ioOverheadPerBlock = 0.001; // 0.1% per block
var overhead = numBlocks * ioOverheadPerBlock;
// Cap overhead at 20%
return Math.Min(overhead * 100, 20.0);
}
}
/// <summary>
/// Strategies for checkpointing operations
/// </summary>
public enum CheckpointStrategy
{
/// <summary>No checkpointing</summary>
None,
/// <summary>Checkpoint every √n operations</summary>
SqrtN,
/// <summary>Checkpoint at fixed intervals</summary>
Linear,
/// <summary>Checkpoint at logarithmic intervals</summary>
Logarithmic
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Core functionality for SqrtSpace SpaceTime - Memory-efficient algorithms using √n space-time tradeoffs</Description>
<PackageId>SqrtSpace.SpaceTime.Core</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<InternalsVisibleTo Include="SqrtSpace.SpaceTime.Linq" />
<InternalsVisibleTo Include="SqrtSpace.SpaceTime.Collections" />
<InternalsVisibleTo Include="SqrtSpace.SpaceTime.EntityFramework" />
<InternalsVisibleTo Include="SqrtSpace.SpaceTime.AspNetCore" />
<InternalsVisibleTo Include="SqrtSpace.SpaceTime.Tests" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="System.Linq.Async" Version="6.0.3" />
<PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.7" />
</ItemGroup>
</Project>

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using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
namespace SqrtSpace.SpaceTime.Diagnostics;
/// <summary>
/// Extension methods for configuring SpaceTime diagnostics
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Adds SpaceTime diagnostics services
/// </summary>
public static IServiceCollection AddSpaceTimeDiagnostics(
this IServiceCollection services,
Action<DiagnosticsOptions>? configure = null)
{
var options = new DiagnosticsOptions();
configure?.Invoke(options);
// Register options
services.AddSingleton(options);
// Register diagnostics service
services.TryAddSingleton<ISpaceTimeDiagnostics, SpaceTimeDiagnostics>();
return services;
}
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
namespace SqrtSpace.SpaceTime.Diagnostics;
/// <summary>
/// Central diagnostics and monitoring for SpaceTime operations
/// </summary>
public class SpaceTimeDiagnostics : ISpaceTimeDiagnostics
{
private readonly Meter _meter;
private readonly ActivitySource _activitySource;
private readonly ILogger<SpaceTimeDiagnostics> _logger;
private readonly DiagnosticsOptions _options;
private readonly ConcurrentDictionary<string, OperationTracker> _operations;
private readonly ConcurrentDictionary<string, MemorySnapshot> _memorySnapshots;
private readonly Timer _snapshotTimer;
// Metrics
private readonly Counter<long> _operationCounter;
private readonly Histogram<double> _operationDuration;
private readonly Histogram<long> _memoryUsage;
private readonly Histogram<long> _externalStorageUsage;
private readonly ObservableGauge<double> _memoryEfficiency;
private readonly ObservableGauge<long> _activeOperations;
public SpaceTimeDiagnostics(
ILogger<SpaceTimeDiagnostics> logger,
DiagnosticsOptions? options = null)
{
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_options = options ?? new DiagnosticsOptions();
_operations = new ConcurrentDictionary<string, OperationTracker>();
_memorySnapshots = new ConcurrentDictionary<string, MemorySnapshot>();
// Initialize metrics
_meter = new Meter("Ubiquity.SpaceTime", "1.0");
_activitySource = new ActivitySource("Ubiquity.SpaceTime");
_operationCounter = _meter.CreateCounter<long>(
"spacetime.operations.total",
"operations",
"Total number of SpaceTime operations");
_operationDuration = _meter.CreateHistogram<double>(
"spacetime.operation.duration",
"milliseconds",
"Duration of SpaceTime operations");
_memoryUsage = _meter.CreateHistogram<long>(
"spacetime.memory.usage",
"bytes",
"Memory usage by SpaceTime operations");
_externalStorageUsage = _meter.CreateHistogram<long>(
"spacetime.storage.usage",
"bytes",
"External storage usage");
_memoryEfficiency = _meter.CreateObservableGauge(
"spacetime.memory.efficiency",
() => CalculateMemoryEfficiency(),
"ratio",
"Memory efficiency ratio (saved/total)");
_activeOperations = _meter.CreateObservableGauge(
"spacetime.operations.active",
() => (long)_operations.Count(o => o.Value.IsActive),
"operations",
"Number of active operations");
_snapshotTimer = new Timer(TakeMemorySnapshot, null, TimeSpan.Zero, _options.SnapshotInterval);
}
public IOperationScope StartOperation(string operationName, OperationType type, Dictionary<string, object>? tags = null)
{
var operationId = Guid.NewGuid().ToString();
var activity = _activitySource.StartActivity(operationName, ActivityKind.Internal);
if (activity != null && tags != null)
{
foreach (var tag in tags)
{
activity.SetTag(tag.Key, tag.Value);
}
}
var tracker = new OperationTracker
{
Id = operationId,
Name = operationName,
Type = type,
StartTime = DateTime.UtcNow,
InitialMemory = GC.GetTotalMemory(false),
Activity = activity
};
_operations[operationId] = tracker;
_operationCounter.Add(1, new KeyValuePair<string, object?>("type", type.ToString()));
return new OperationScope(this, tracker);
}
public void RecordMemoryUsage(string operationId, long memoryUsed, MemoryType memoryType)
{
if (_operations.TryGetValue(operationId, out var tracker))
{
tracker.MemoryUsage[memoryType] = memoryUsed;
_memoryUsage.Record(memoryUsed,
new KeyValuePair<string, object?>("operation", tracker.Name),
new KeyValuePair<string, object?>("type", memoryType.ToString()));
}
}
public void RecordExternalStorageUsage(string operationId, long bytesUsed)
{
if (_operations.TryGetValue(operationId, out var tracker))
{
tracker.ExternalStorageUsed = bytesUsed;
_externalStorageUsage.Record(bytesUsed,
new KeyValuePair<string, object?>("operation", tracker.Name));
}
}
public void RecordCheckpoint(string operationId, string checkpointId, long itemsProcessed)
{
if (_operations.TryGetValue(operationId, out var tracker))
{
tracker.Checkpoints.Add(new CheckpointInfo
{
Id = checkpointId,
Timestamp = DateTime.UtcNow,
ItemsProcessed = itemsProcessed
});
tracker.Activity?.AddEvent(new ActivityEvent("Checkpoint",
tags: new ActivityTagsCollection
{
{ "checkpoint.id", checkpointId },
{ "items.processed", itemsProcessed }
}));
}
}
public void RecordError(string operationId, Exception exception)
{
if (_operations.TryGetValue(operationId, out var tracker))
{
tracker.Errors.Add(new ErrorInfo
{
Timestamp = DateTime.UtcNow,
ExceptionType = exception.GetType().Name,
Message = exception.Message,
StackTrace = exception.StackTrace
});
tracker.Activity?.SetStatus(ActivityStatusCode.Error, exception.Message);
tracker.Activity?.AddEvent(new ActivityEvent("exception",
tags: new ActivityTagsCollection
{
{ "exception.type", exception.GetType().FullName },
{ "exception.message", exception.Message },
{ "exception.stacktrace", exception.StackTrace }
}));
}
}
public async Task<DiagnosticReport> GenerateReportAsync(TimeSpan period)
{
var endTime = DateTime.UtcNow;
var startTime = endTime.Subtract(period);
var relevantOperations = _operations.Values
.Where(o => o.StartTime >= startTime)
.ToList();
var report = new DiagnosticReport
{
Period = period,
GeneratedAt = endTime,
TotalOperations = relevantOperations.Count,
OperationsByType = relevantOperations
.GroupBy(o => o.Type)
.ToDictionary(g => g.Key, g => g.Count()),
AverageMemoryUsage = relevantOperations.Any()
? relevantOperations.Average(o => o.TotalMemoryUsed)
: 0,
TotalExternalStorageUsed = relevantOperations.Sum(o => o.ExternalStorageUsed),
AverageDuration = relevantOperations
.Where(o => o.EndTime.HasValue)
.Select(o => (o.EndTime!.Value - o.StartTime).TotalMilliseconds)
.DefaultIfEmpty(0)
.Average(),
ErrorRate = relevantOperations.Any()
? (double)relevantOperations.Count(o => o.Errors.Any()) / relevantOperations.Count
: 0,
MemoryEfficiencyRatio = CalculateMemoryEfficiency(),
TopOperationsByMemory = relevantOperations
.OrderByDescending(o => o.TotalMemoryUsed)
.Take(10)
.Select(o => new OperationSummary
{
Name = o.Name,
Type = o.Type,
MemoryUsed = o.TotalMemoryUsed,
Duration = o.EndTime.HasValue
? (o.EndTime.Value - o.StartTime).TotalMilliseconds
: 0
})
.ToList(),
MemorySnapshots = _memorySnapshots.Values
.Where(s => s.Timestamp >= startTime)
.OrderBy(s => s.Timestamp)
.ToList()
};
return report;
}
public HealthStatus GetHealthStatus()
{
var activeOps = _operations.Values.Count(o => o.IsActive);
var recentErrors = _operations.Values
.Where(o => o.StartTime >= DateTime.UtcNow.AddMinutes(-5))
.Count(o => o.Errors.Any());
var memoryPressure = GC.GetTotalMemory(false) > _options.MemoryThreshold;
if (recentErrors > 10 || memoryPressure)
{
return new HealthStatus
{
Status = Health.Unhealthy,
Message = $"High error rate ({recentErrors}) or memory pressure",
Details = new Dictionary<string, object>
{
["active_operations"] = activeOps,
["recent_errors"] = recentErrors,
["memory_pressure"] = memoryPressure
}
};
}
if (activeOps > _options.MaxConcurrentOperations * 0.8)
{
return new HealthStatus
{
Status = Health.Degraded,
Message = "High number of active operations",
Details = new Dictionary<string, object>
{
["active_operations"] = activeOps,
["max_operations"] = _options.MaxConcurrentOperations
}
};
}
return new HealthStatus
{
Status = Health.Healthy,
Message = "All systems operational",
Details = new Dictionary<string, object>
{
["active_operations"] = activeOps,
["memory_efficiency"] = CalculateMemoryEfficiency()
}
};
}
private void CompleteOperation(OperationTracker tracker)
{
tracker.EndTime = DateTime.UtcNow;
tracker.FinalMemory = GC.GetTotalMemory(false);
var duration = (tracker.EndTime.Value - tracker.StartTime).TotalMilliseconds;
_operationDuration.Record(duration,
new KeyValuePair<string, object?>("operation", tracker.Name),
new KeyValuePair<string, object?>("type", tracker.Type.ToString()));
tracker.Activity?.Dispose();
// Clean up old operations
if (_operations.Count > _options.MaxTrackedOperations)
{
var toRemove = _operations
.Where(o => o.Value.EndTime.HasValue &&
o.Value.EndTime.Value < DateTime.UtcNow.AddHours(-1))
.Select(o => o.Key)
.Take(_operations.Count - _options.MaxTrackedOperations / 2)
.ToList();
foreach (var key in toRemove)
{
_operations.TryRemove(key, out _);
}
}
}
private double CalculateMemoryEfficiency()
{
var recentOps = _operations.Values
.Where(o => o.StartTime >= DateTime.UtcNow.AddMinutes(-5))
.ToList();
if (!recentOps.Any())
return 0;
var totalMemoryUsed = recentOps.Sum(o => o.TotalMemoryUsed);
var externalStorageUsed = recentOps.Sum(o => o.ExternalStorageUsed);
if (totalMemoryUsed + externalStorageUsed == 0)
return 0;
// Efficiency = memory saved by using external storage
return (double)externalStorageUsed / (totalMemoryUsed + externalStorageUsed);
}
private void TakeMemorySnapshot(object? state)
{
var snapshot = new MemorySnapshot
{
Timestamp = DateTime.UtcNow,
TotalMemory = GC.GetTotalMemory(false),
Gen0Collections = GC.CollectionCount(0),
Gen1Collections = GC.CollectionCount(1),
Gen2Collections = GC.CollectionCount(2),
ActiveOperations = _operations.Count(o => o.Value.IsActive),
TotalOperations = _operations.Count
};
_memorySnapshots[snapshot.Timestamp.ToString("O")] = snapshot;
// Clean up old snapshots
var cutoff = DateTime.UtcNow.Subtract(_options.SnapshotRetention);
var oldSnapshots = _memorySnapshots
.Where(s => s.Value.Timestamp < cutoff)
.Select(s => s.Key)
.ToList();
foreach (var key in oldSnapshots)
{
_memorySnapshots.TryRemove(key, out _);
}
}
public void Dispose()
{
_snapshotTimer?.Dispose();
_meter?.Dispose();
_activitySource?.Dispose();
}
private class OperationScope : IOperationScope
{
private readonly SpaceTimeDiagnostics _diagnostics;
private readonly OperationTracker _tracker;
private bool _disposed;
public string OperationId => _tracker.Id;
public OperationScope(SpaceTimeDiagnostics diagnostics, OperationTracker tracker)
{
_diagnostics = diagnostics;
_tracker = tracker;
}
public void RecordMetric(string name, double value, Dictionary<string, object>? tags = null)
{
_tracker.Metrics[name] = value;
_tracker.Activity?.SetTag($"metric.{name}", value);
}
public void AddTag(string key, object value)
{
_tracker.Tags[key] = value;
_tracker.Activity?.SetTag(key, value);
}
public void Dispose()
{
if (!_disposed)
{
_diagnostics.CompleteOperation(_tracker);
_disposed = true;
}
}
}
}
// Supporting classes
public interface ISpaceTimeDiagnostics : IDisposable
{
IOperationScope StartOperation(string operationName, OperationType type, Dictionary<string, object>? tags = null);
void RecordMemoryUsage(string operationId, long memoryUsed, MemoryType memoryType);
void RecordExternalStorageUsage(string operationId, long bytesUsed);
void RecordCheckpoint(string operationId, string checkpointId, long itemsProcessed);
void RecordError(string operationId, Exception exception);
Task<DiagnosticReport> GenerateReportAsync(TimeSpan period);
HealthStatus GetHealthStatus();
}
public interface IOperationScope : IDisposable
{
string OperationId { get; }
void RecordMetric(string name, double value, Dictionary<string, object>? tags = null);
void AddTag(string key, object value);
}
public enum OperationType
{
Sort,
Group,
Join,
Filter,
Aggregate,
Checkpoint,
ExternalStorage,
Cache,
Custom
}
public enum MemoryType
{
Heap,
Buffer,
Cache,
External
}
public class DiagnosticsOptions
{
public TimeSpan SnapshotInterval { get; set; } = TimeSpan.FromMinutes(1);
public TimeSpan SnapshotRetention { get; set; } = TimeSpan.FromHours(24);
public int MaxTrackedOperations { get; set; } = 10000;
public int MaxConcurrentOperations { get; set; } = 100;
public long MemoryThreshold { get; set; } = 1024L * 1024 * 1024; // 1GB
}
public class DiagnosticReport
{
public TimeSpan Period { get; set; }
public DateTime GeneratedAt { get; set; }
public int TotalOperations { get; set; }
public Dictionary<OperationType, int> OperationsByType { get; set; } = new();
public double AverageMemoryUsage { get; set; }
public long TotalExternalStorageUsed { get; set; }
public double AverageDuration { get; set; }
public double ErrorRate { get; set; }
public double MemoryEfficiencyRatio { get; set; }
public List<OperationSummary> TopOperationsByMemory { get; set; } = new();
public List<MemorySnapshot> MemorySnapshots { get; set; } = new();
}
public class OperationSummary
{
public string Name { get; set; } = "";
public OperationType Type { get; set; }
public long MemoryUsed { get; set; }
public double Duration { get; set; }
}
public class MemorySnapshot
{
public DateTime Timestamp { get; set; }
public long TotalMemory { get; set; }
public int Gen0Collections { get; set; }
public int Gen1Collections { get; set; }
public int Gen2Collections { get; set; }
public int ActiveOperations { get; set; }
public int TotalOperations { get; set; }
}
public class HealthStatus
{
public Health Status { get; set; }
public string Message { get; set; } = "";
public Dictionary<string, object> Details { get; set; } = new();
}
public enum Health
{
Healthy,
Degraded,
Unhealthy
}
// Internal classes
internal class OperationTracker
{
public string Id { get; set; } = "";
public string Name { get; set; } = "";
public OperationType Type { get; set; }
public DateTime StartTime { get; set; }
public DateTime? EndTime { get; set; }
public long InitialMemory { get; set; }
public long FinalMemory { get; set; }
public Activity? Activity { get; set; }
public bool IsActive => !EndTime.HasValue;
public Dictionary<MemoryType, long> MemoryUsage { get; } = new();
public long ExternalStorageUsed { get; set; }
public List<CheckpointInfo> Checkpoints { get; } = new();
public List<ErrorInfo> Errors { get; } = new();
public Dictionary<string, double> Metrics { get; } = new();
public Dictionary<string, object> Tags { get; } = new();
public long TotalMemoryUsed => MemoryUsage.Values.Sum();
}
internal class CheckpointInfo
{
public string Id { get; set; } = "";
public DateTime Timestamp { get; set; }
public long ItemsProcessed { get; set; }
}
internal class ErrorInfo
{
public DateTime Timestamp { get; set; }
public string ExceptionType { get; set; } = "";
public string Message { get; set; } = "";
public string? StackTrace { get; set; }
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Diagnostics, monitoring, and telemetry for SpaceTime operations</Description>
<PackageTags>diagnostics;monitoring;telemetry;metrics;tracing;spacetime</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Diagnostics</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
<PackageReference Include="System.Diagnostics.DiagnosticSource" Version="9.0.7" />
<PackageReference Include="OpenTelemetry" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Api" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.12.0" />
<PackageReference Include="OpenTelemetry.Exporter.Prometheus.AspNetCore" Version="1.9.0-beta.2" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using OpenTelemetry;
using OpenTelemetry.Metrics;
using OpenTelemetry.Resources;
using OpenTelemetry.Trace;
namespace SqrtSpace.SpaceTime.Diagnostics.Telemetry;
/// <summary>
/// OpenTelemetry integration for SpaceTime diagnostics
/// </summary>
public static class SpaceTimeTelemetry
{
public const string ActivitySourceName = "Ubiquity.SpaceTime";
public const string MeterName = "Ubiquity.SpaceTime";
/// <summary>
/// Configures OpenTelemetry for SpaceTime
/// </summary>
public static IServiceCollection AddSpaceTimeTelemetry(
this IServiceCollection services,
Action<SpaceTimeTelemetryOptions>? configure = null)
{
var options = new SpaceTimeTelemetryOptions();
configure?.Invoke(options);
services.AddSingleton<ISpaceTimeDiagnostics>(provider =>
{
var logger = provider.GetRequiredService<Microsoft.Extensions.Logging.ILogger<SpaceTimeDiagnostics>>();
return new SpaceTimeDiagnostics(logger, options.DiagnosticsOptions);
});
// Configure OpenTelemetry
services.AddOpenTelemetry()
.ConfigureResource(resource => resource
.AddService(serviceName: options.ServiceName)
.AddAttributes(new Dictionary<string, object>
{
["service.version"] = options.ServiceVersion,
["deployment.environment"] = options.Environment
}))
.WithTracing(tracing =>
{
tracing
.AddSource(ActivitySourceName)
.SetSampler(new TraceIdRatioBasedSampler(options.SamplingRatio))
.AddHttpClientInstrumentation()
.AddAspNetCoreInstrumentation();
if (options.EnableConsoleExporter)
{
tracing.AddConsoleExporter();
}
if (options.EnableOtlpExporter)
{
tracing.AddOtlpExporter(otlp =>
{
otlp.Endpoint = new Uri(options.OtlpEndpoint);
otlp.Protocol = options.OtlpProtocol;
});
}
// Add custom processor for SpaceTime-specific enrichment
tracing.AddProcessor(new SpaceTimeActivityProcessor());
})
.WithMetrics(metrics =>
{
metrics
.AddMeter(MeterName)
.AddHttpClientInstrumentation()
.AddAspNetCoreInstrumentation()
.AddView(instrument =>
{
// Custom view for operation duration histogram
if (instrument.Name == "spacetime.operation.duration")
{
return new ExplicitBucketHistogramConfiguration
{
Boundaries = new double[] { 0, 10, 50, 100, 500, 1000, 5000, 10000 }
};
}
// Custom view for memory usage histogram
if (instrument.Name == "spacetime.memory.usage")
{
return new ExplicitBucketHistogramConfiguration
{
Boundaries = new double[]
{
0,
1024, // 1KB
10240, // 10KB
102400, // 100KB
1048576, // 1MB
10485760, // 10MB
104857600, // 100MB
1073741824 // 1GB
}
};
}
return null;
});
if (options.EnableConsoleExporter)
{
metrics.AddConsoleExporter();
}
if (options.EnablePrometheusExporter)
{
metrics.AddPrometheusExporter();
}
if (options.EnableOtlpExporter)
{
metrics.AddOtlpExporter(otlp =>
{
otlp.Endpoint = new Uri(options.OtlpEndpoint);
otlp.Protocol = options.OtlpProtocol;
});
}
});
return services;
}
/// <summary>
/// Creates a diagnostic scope for manual instrumentation
/// </summary>
public static IDisposable CreateScope(
string operationName,
OperationType operationType,
Dictionary<string, object>? tags = null)
{
var activitySource = new ActivitySource(ActivitySourceName);
var activity = activitySource.StartActivity(operationName, ActivityKind.Internal);
if (activity != null)
{
activity.SetTag("spacetime.operation.type", operationType.ToString());
if (tags != null)
{
foreach (var tag in tags)
{
activity.SetTag(tag.Key, tag.Value);
}
}
}
return new ActivityScope(activity);
}
private class ActivityScope : IDisposable
{
private readonly Activity? _activity;
public ActivityScope(Activity? activity)
{
_activity = activity;
}
public void Dispose()
{
_activity?.Dispose();
}
}
}
/// <summary>
/// Custom activity processor for SpaceTime-specific enrichment
/// </summary>
public class SpaceTimeActivityProcessor : BaseProcessor<Activity>
{
public override void OnStart(Activity activity)
{
// Add SpaceTime-specific tags
activity.SetTag("spacetime.version", "1.0");
activity.SetTag("spacetime.thread_id", Environment.CurrentManagedThreadId);
// Add memory info at start
activity.SetTag("spacetime.memory.start", GC.GetTotalMemory(false));
}
public override void OnEnd(Activity activity)
{
// Add memory info at end
activity.SetTag("spacetime.memory.end", GC.GetTotalMemory(false));
// Calculate memory delta
if (activity.GetTagItem("spacetime.memory.start") is long startMemory)
{
var endMemory = GC.GetTotalMemory(false);
activity.SetTag("spacetime.memory.delta", endMemory - startMemory);
}
// Add GC info
activity.SetTag("spacetime.gc.gen0", GC.CollectionCount(0));
activity.SetTag("spacetime.gc.gen1", GC.CollectionCount(1));
activity.SetTag("spacetime.gc.gen2", GC.CollectionCount(2));
}
}
public class SpaceTimeTelemetryOptions
{
public string ServiceName { get; set; } = "SpaceTimeService";
public string ServiceVersion { get; set; } = "1.0.0";
public string Environment { get; set; } = "production";
public double SamplingRatio { get; set; } = 1.0;
public bool EnableConsoleExporter { get; set; }
public bool EnableOtlpExporter { get; set; }
public bool EnablePrometheusExporter { get; set; }
public string OtlpEndpoint { get; set; } = "http://localhost:4317";
public OpenTelemetry.Exporter.OtlpExportProtocol OtlpProtocol { get; set; } = OpenTelemetry.Exporter.OtlpExportProtocol.Grpc;
public DiagnosticsOptions DiagnosticsOptions { get; set; } = new();
}
/// <summary>
/// Extension methods for easy instrumentation
/// </summary>
public static class DiagnosticExtensions
{
/// <summary>
/// Wraps an operation with diagnostics
/// </summary>
public static async Task<T> WithDiagnosticsAsync<T>(
this ISpaceTimeDiagnostics diagnostics,
string operationName,
OperationType type,
Func<IOperationScope, Task<T>> operation,
Dictionary<string, object>? tags = null)
{
using var scope = diagnostics.StartOperation(operationName, type, tags);
try
{
var result = await operation(scope);
return result;
}
catch (Exception ex)
{
diagnostics.RecordError(scope.OperationId, ex);
throw;
}
}
/// <summary>
/// Records memory usage for an operation
/// </summary>
public static void RecordMemoryStats(
this IOperationScope scope,
ISpaceTimeDiagnostics diagnostics)
{
var memory = GC.GetTotalMemory(false);
diagnostics.RecordMemoryUsage(scope.OperationId, memory, MemoryType.Heap);
// Record GC stats
scope.RecordMetric("gc.gen0", GC.CollectionCount(0));
scope.RecordMetric("gc.gen1", GC.CollectionCount(1));
scope.RecordMetric("gc.gen2", GC.CollectionCount(2));
}
}

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using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Distributed;
/// <summary>
/// Registry for distributed nodes
/// </summary>
public interface INodeRegistry
{
Task<bool> RegisterNodeAsync(NodeInfo node, CancellationToken cancellationToken = default);
Task<bool> UnregisterNodeAsync(string nodeId, CancellationToken cancellationToken = default);
Task<List<NodeInfo>> GetActiveNodesAsync(CancellationToken cancellationToken = default);
Task<NodeInfo?> GetNodeAsync(string nodeId, CancellationToken cancellationToken = default);
Task UpdateNodeHeartbeatAsync(string nodeId, CancellationToken cancellationToken = default);
Task<bool> IsLeader(string nodeId);
Task<string?> GetLeaderNodeIdAsync(CancellationToken cancellationToken = default);
event EventHandler<NodeEvent>? NodeStatusChanged;
}
/// <summary>
/// Message bus for distributed communication
/// </summary>
public interface IMessageBus
{
Task PublishAsync<T>(string topic, T message, CancellationToken cancellationToken = default);
Task<ISubscription> SubscribeAsync<T>(string topic, Action<T> handler, CancellationToken cancellationToken = default);
Task<TResponse?> RequestAsync<TRequest, TResponse>(string topic, TRequest request, TimeSpan timeout, CancellationToken cancellationToken = default);
}
public interface ISubscription : IAsyncDisposable
{
string Topic { get; }
Task UnsubscribeAsync();
}
public class NodeInfo
{
public string Id { get; set; } = "";
public string Hostname { get; set; } = "";
public int Port { get; set; }
public NodeCapabilities Capabilities { get; set; } = new();
public NodeStatus Status { get; set; }
public DateTime LastHeartbeat { get; set; }
public double CurrentLoad { get; set; }
public long AvailableMemory { get; set; }
public Dictionary<string, string> Metadata { get; set; } = new();
}
public class NodeCapabilities
{
public long MaxMemory { get; set; }
public int MaxConcurrentWorkloads { get; set; }
public List<string> SupportedFeatures { get; set; } = new();
}
public enum NodeStatus
{
Registering,
Active,
Busy,
Draining,
Offline
}
public class NodeEvent
{
public string NodeId { get; set; } = "";
public NodeEventType Type { get; set; }
public DateTime Timestamp { get; set; }
public NodeInfo? Node { get; set; }
}
public enum NodeEventType
{
NodeRegistered,
NodeUnregistered,
NodeStatusChanged,
LeaderElected
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace SqrtSpace.SpaceTime.Distributed.Infrastructure;
/// <summary>
/// Simple in-memory node registry implementation
/// </summary>
internal class SimpleNodeRegistry : INodeRegistry
{
private readonly Dictionary<string, NodeInfo> _nodes = new();
private readonly object _lock = new();
public event EventHandler<NodeEvent>? NodeStatusChanged;
public Task<bool> RegisterNodeAsync(NodeInfo node, CancellationToken cancellationToken = default)
{
lock (_lock)
{
_nodes[node.Id] = node;
NodeStatusChanged?.Invoke(this, new NodeEvent
{
NodeId = node.Id,
Type = NodeEventType.NodeRegistered,
Timestamp = DateTime.UtcNow,
Node = node
});
}
return Task.FromResult(true);
}
public Task<bool> UnregisterNodeAsync(string nodeId, CancellationToken cancellationToken = default)
{
lock (_lock)
{
var result = _nodes.Remove(nodeId);
if (result)
{
NodeStatusChanged?.Invoke(this, new NodeEvent
{
NodeId = nodeId,
Type = NodeEventType.NodeUnregistered,
Timestamp = DateTime.UtcNow
});
}
return Task.FromResult(result);
}
}
public Task<List<NodeInfo>> GetActiveNodesAsync(CancellationToken cancellationToken = default)
{
lock (_lock)
{
return Task.FromResult(_nodes.Values.Where(n => n.Status == NodeStatus.Active).ToList());
}
}
public Task<NodeInfo?> GetNodeAsync(string nodeId, CancellationToken cancellationToken = default)
{
lock (_lock)
{
_nodes.TryGetValue(nodeId, out var node);
return Task.FromResult(node);
}
}
public Task<bool> IsLeader(string nodeId)
{
lock (_lock)
{
// Simple implementation: first registered node is leader
var firstNode = _nodes.Values.FirstOrDefault();
return Task.FromResult(firstNode?.Id == nodeId);
}
}
public Task<string?> GetLeaderNodeIdAsync(CancellationToken cancellationToken = default)
{
lock (_lock)
{
var firstNode = _nodes.Values.FirstOrDefault();
return Task.FromResult(firstNode?.Id);
}
}
public Task UpdateNodeHeartbeatAsync(string nodeId, CancellationToken cancellationToken = default)
{
lock (_lock)
{
if (_nodes.TryGetValue(nodeId, out var node))
{
node.LastHeartbeat = DateTime.UtcNow;
}
}
return Task.CompletedTask;
}
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Hosting;
using SqrtSpace.SpaceTime.Distributed.Infrastructure;
namespace SqrtSpace.SpaceTime.Distributed;
/// <summary>
/// Extension methods for configuring distributed SpaceTime services
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Adds SpaceTime distributed processing services
/// </summary>
public static IServiceCollection AddSpaceTimeDistributed(
this IServiceCollection services,
Action<DistributedOptions>? configure = null)
{
var options = new DistributedOptions();
configure?.Invoke(options);
// Register options
services.AddSingleton(options);
// Register node registry
services.TryAddSingleton<INodeRegistry, Infrastructure.SimpleNodeRegistry>();
// Register coordinator
services.TryAddSingleton<ISpaceTimeCoordinator, SpaceTimeCoordinator>();
// Register node service
services.TryAddSingleton<SpaceTimeNode>();
services.AddHostedService(provider => provider.GetRequiredService<SpaceTimeNode>());
return services;
}
}
/// <summary>
/// Configuration options for distributed SpaceTime
/// </summary>
public class DistributedOptions
{
/// <summary>
/// Unique identifier for this node
/// </summary>
public string NodeId { get; set; } = Environment.MachineName;
/// <summary>
/// Endpoint for coordination service (e.g., Redis)
/// </summary>
public string CoordinationEndpoint { get; set; } = "redis://localhost:6379";
/// <summary>
/// Enable automatic node discovery
/// </summary>
public bool EnableNodeDiscovery { get; set; } = true;
/// <summary>
/// Heartbeat interval for node health checks
/// </summary>
public TimeSpan HeartbeatInterval { get; set; } = TimeSpan.FromSeconds(30);
/// <summary>
/// Timeout for considering a node as failed
/// </summary>
public TimeSpan NodeTimeout { get; set; } = TimeSpan.FromMinutes(2);
/// <summary>
/// Maximum number of concurrent distributed operations
/// </summary>
public int MaxConcurrentOperations { get; set; } = 10;
/// <summary>
/// Enable automatic work redistribution on node failure
/// </summary>
public bool EnableFailover { get; set; } = true;
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Distributed;
/// <summary>
/// Coordinates distributed SpaceTime operations across multiple nodes
/// </summary>
public class SpaceTimeCoordinator : ISpaceTimeCoordinator
{
private readonly INodeRegistry _nodeRegistry;
private readonly IMessageBus _messageBus;
private readonly ILogger<SpaceTimeCoordinator> _logger;
private readonly CoordinatorOptions _options;
private readonly ConcurrentDictionary<string, PartitionInfo> _partitions;
private readonly ConcurrentDictionary<string, WorkloadInfo> _workloads;
private readonly Timer _rebalanceTimer;
private readonly SemaphoreSlim _coordinationLock;
public string NodeId { get; }
public bool IsLeader => _nodeRegistry.IsLeader(NodeId).GetAwaiter().GetResult();
public SpaceTimeCoordinator(
INodeRegistry nodeRegistry,
IMessageBus messageBus,
ILogger<SpaceTimeCoordinator> logger,
CoordinatorOptions? options = null)
{
_nodeRegistry = nodeRegistry ?? throw new ArgumentNullException(nameof(nodeRegistry));
_messageBus = messageBus ?? throw new ArgumentNullException(nameof(messageBus));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_options = options ?? new CoordinatorOptions();
NodeId = Guid.NewGuid().ToString();
_partitions = new ConcurrentDictionary<string, PartitionInfo>();
_workloads = new ConcurrentDictionary<string, WorkloadInfo>();
_coordinationLock = new SemaphoreSlim(1, 1);
_rebalanceTimer = new Timer(
RebalanceWorkloads,
null,
TimeSpan.FromSeconds(30),
TimeSpan.FromSeconds(30));
}
public async Task<PartitionAssignment> RequestPartitionAsync(
string workloadId,
long dataSize,
CancellationToken cancellationToken = default)
{
// Calculate optimal partition count using √n
var optimalPartitions = SpaceTimeCalculator.CalculateSqrtInterval(dataSize);
// Register workload
var workload = new WorkloadInfo
{
Id = workloadId,
DataSize = dataSize,
RequestedPartitions = optimalPartitions,
CreatedAt = DateTime.UtcNow
};
_workloads[workloadId] = workload;
// Get available nodes
var nodes = await _nodeRegistry.GetActiveNodesAsync(cancellationToken);
// Assign partitions to nodes
var assignments = await AssignPartitionsAsync(workload, nodes, cancellationToken);
// Notify nodes of assignments
await NotifyPartitionAssignmentsAsync(assignments, cancellationToken);
return new PartitionAssignment
{
WorkloadId = workloadId,
Partitions = assignments,
Strategy = PartitionStrategy.SqrtN
};
}
public async Task<CheckpointCoordination> CoordinateCheckpointAsync(
string workloadId,
string checkpointId,
CancellationToken cancellationToken = default)
{
if (!_workloads.TryGetValue(workloadId, out var workload))
{
throw new InvalidOperationException($"Workload {workloadId} not found");
}
var coordination = new CheckpointCoordination
{
CheckpointId = checkpointId,
WorkloadId = workloadId,
Timestamp = DateTime.UtcNow,
Status = CheckpointStatus.InProgress
};
// Broadcast checkpoint request to all nodes with this workload
var message = new CheckpointMessage
{
Type = MessageType.CheckpointRequest,
CheckpointId = checkpointId,
WorkloadId = workloadId
};
await _messageBus.PublishAsync($"checkpoint.{workloadId}", message, cancellationToken);
// Wait for acknowledgments
var acks = await WaitForCheckpointAcksAsync(checkpointId, workload, cancellationToken);
coordination.Status = acks.All(a => a.Success)
? CheckpointStatus.Completed
: CheckpointStatus.Failed;
coordination.NodeAcknowledgments = acks;
return coordination;
}
public async Task<WorkloadStatistics> GetWorkloadStatisticsAsync(
string workloadId,
CancellationToken cancellationToken = default)
{
if (!_workloads.TryGetValue(workloadId, out var workload))
{
throw new InvalidOperationException($"Workload {workloadId} not found");
}
// Gather statistics from all nodes
var nodeStats = await GatherNodeStatisticsAsync(workloadId, cancellationToken);
return new WorkloadStatistics
{
WorkloadId = workloadId,
TotalDataSize = workload.DataSize,
ProcessedSize = nodeStats.Sum(s => s.ProcessedSize),
MemoryUsage = nodeStats.Sum(s => s.MemoryUsage),
ActivePartitions = nodeStats.Sum(s => s.ActivePartitions),
CompletedPartitions = nodeStats.Sum(s => s.CompletedPartitions),
AverageProcessingRate = nodeStats.Average(s => s.ProcessingRate),
NodeStatistics = nodeStats
};
}
public async Task<RebalanceResult> RebalanceWorkloadAsync(
string workloadId,
CancellationToken cancellationToken = default)
{
await _coordinationLock.WaitAsync(cancellationToken);
try
{
if (!_workloads.TryGetValue(workloadId, out var workload))
{
throw new InvalidOperationException($"Workload {workloadId} not found");
}
var nodes = await _nodeRegistry.GetActiveNodesAsync(cancellationToken);
var currentAssignments = GetCurrentAssignments(workloadId);
// Check if rebalancing is needed
var imbalance = CalculateImbalance(currentAssignments, nodes);
if (imbalance < _options.RebalanceThreshold)
{
return new RebalanceResult
{
WorkloadId = workloadId,
RebalanceNeeded = false,
Message = "Workload is already balanced"
};
}
// Calculate new assignments
var newAssignments = await CalculateOptimalAssignmentsAsync(
workload,
nodes,
currentAssignments,
cancellationToken);
// Execute rebalancing
var migrations = await ExecuteRebalancingAsync(
currentAssignments,
newAssignments,
cancellationToken);
return new RebalanceResult
{
WorkloadId = workloadId,
RebalanceNeeded = true,
MigratedPartitions = migrations.Count,
OldImbalance = imbalance,
NewImbalance = CalculateImbalance(newAssignments, nodes)
};
}
finally
{
_coordinationLock.Release();
}
}
private async Task<List<Partition>> AssignPartitionsAsync(
WorkloadInfo workload,
List<NodeInfo> nodes,
CancellationToken cancellationToken)
{
var partitions = new List<Partition>();
var partitionSize = workload.DataSize / workload.RequestedPartitions;
// Use round-robin with capacity awareness
var nodeIndex = 0;
var nodeLoads = nodes.ToDictionary(n => n.Id, n => 0L);
for (int i = 0; i < workload.RequestedPartitions; i++)
{
// Find node with least load
var targetNode = nodes
.OrderBy(n => nodeLoads[n.Id])
.ThenBy(n => n.CurrentLoad)
.First();
var partition = new Partition
{
Id = $"{workload.Id}_p{i}",
WorkloadId = workload.Id,
NodeId = targetNode.Id,
StartOffset = i * partitionSize,
EndOffset = (i + 1) * partitionSize,
Status = PartitionStatus.Assigned
};
partitions.Add(partition);
_partitions[partition.Id] = new PartitionInfo
{
Partition = partition,
AssignedAt = DateTime.UtcNow
};
nodeLoads[targetNode.Id] += partitionSize;
}
return partitions;
}
private async Task NotifyPartitionAssignmentsAsync(
List<Partition> partitions,
CancellationToken cancellationToken)
{
var tasks = partitions
.GroupBy(p => p.NodeId)
.Select(group => NotifyNodeAsync(group.Key, group.ToList(), cancellationToken));
await Task.WhenAll(tasks);
}
private async Task NotifyNodeAsync(
string nodeId,
List<Partition> partitions,
CancellationToken cancellationToken)
{
var message = new PartitionAssignmentMessage
{
Type = MessageType.PartitionAssignment,
NodeId = nodeId,
Partitions = partitions
};
await _messageBus.PublishAsync($"node.{nodeId}.assignments", message, cancellationToken);
}
private async Task<List<CheckpointAck>> WaitForCheckpointAcksAsync(
string checkpointId,
WorkloadInfo workload,
CancellationToken cancellationToken)
{
var acks = new ConcurrentBag<CheckpointAck>();
var tcs = new TaskCompletionSource<bool>();
// Subscribe to acknowledgments
var subscription = await _messageBus.SubscribeAsync<CheckpointAck>(
$"checkpoint.{checkpointId}.ack",
ack =>
{
acks.Add(ack);
if (acks.Count >= GetExpectedAckCount(workload))
{
tcs.TrySetResult(true);
}
},
cancellationToken);
// Wait for all acks or timeout
using (cancellationToken.Register(() => tcs.TrySetCanceled()))
{
await Task.WhenAny(
tcs.Task,
Task.Delay(_options.CheckpointTimeout));
}
await subscription.DisposeAsync();
return acks.ToList();
}
private int GetExpectedAckCount(WorkloadInfo workload)
{
return _partitions.Values
.Count(p => p.Partition.WorkloadId == workload.Id);
}
private async Task<List<NodeStatistics>> GatherNodeStatisticsAsync(
string workloadId,
CancellationToken cancellationToken)
{
var stats = new ConcurrentBag<NodeStatistics>();
var nodes = await _nodeRegistry.GetActiveNodesAsync(cancellationToken);
var tasks = nodes.Select(async node =>
{
var request = new StatisticsRequest
{
WorkloadId = workloadId,
NodeId = node.Id
};
var response = await _messageBus.RequestAsync<StatisticsRequest, NodeStatistics>(
$"node.{node.Id}.stats",
request,
TimeSpan.FromSeconds(5),
cancellationToken);
if (response != null)
{
stats.Add(response);
}
});
await Task.WhenAll(tasks);
return stats.ToList();
}
private List<Partition> GetCurrentAssignments(string workloadId)
{
return _partitions.Values
.Where(p => p.Partition.WorkloadId == workloadId)
.Select(p => p.Partition)
.ToList();
}
private double CalculateImbalance(List<Partition> assignments, List<NodeInfo> nodes)
{
if (!assignments.Any() || !nodes.Any())
return 0;
var nodeLoads = nodes.ToDictionary(n => n.Id, n => 0L);
foreach (var partition in assignments)
{
if (nodeLoads.ContainsKey(partition.NodeId))
{
nodeLoads[partition.NodeId] += partition.EndOffset - partition.StartOffset;
}
}
var loads = nodeLoads.Values.Where(l => l > 0).ToList();
if (!loads.Any())
return 0;
var avgLoad = loads.Average();
var variance = loads.Sum(l => Math.Pow(l - avgLoad, 2)) / loads.Count;
return Math.Sqrt(variance) / avgLoad;
}
private async Task<List<Partition>> CalculateOptimalAssignmentsAsync(
WorkloadInfo workload,
List<NodeInfo> nodes,
List<Partition> currentAssignments,
CancellationToken cancellationToken)
{
// Use √n strategy for rebalancing
var targetPartitionsPerNode = Math.Max(1, workload.RequestedPartitions / nodes.Count);
var newAssignments = new List<Partition>();
// Group current assignments by node
var nodeAssignments = currentAssignments
.GroupBy(p => p.NodeId)
.ToDictionary(g => g.Key, g => g.ToList());
// Redistribute partitions
var partitionQueue = new Queue<Partition>();
// Collect excess partitions
foreach (var node in nodes)
{
if (nodeAssignments.TryGetValue(node.Id, out var partitions))
{
var excess = partitions.Count - targetPartitionsPerNode;
if (excess > 0)
{
var toMove = partitions.OrderBy(p => p.Id).Take(excess);
foreach (var partition in toMove)
{
partitionQueue.Enqueue(partition);
}
}
}
}
// Assign to underloaded nodes
foreach (var node in nodes)
{
var currentCount = nodeAssignments.TryGetValue(node.Id, out var current)
? current.Count
: 0;
var needed = targetPartitionsPerNode - currentCount;
for (int i = 0; i < needed && partitionQueue.Count > 0; i++)
{
var partition = partitionQueue.Dequeue();
newAssignments.Add(new Partition
{
Id = partition.Id,
WorkloadId = partition.WorkloadId,
NodeId = node.Id,
StartOffset = partition.StartOffset,
EndOffset = partition.EndOffset,
Status = PartitionStatus.Migrating
});
}
}
return newAssignments;
}
private async Task<List<PartitionMigration>> ExecuteRebalancingAsync(
List<Partition> currentAssignments,
List<Partition> newAssignments,
CancellationToken cancellationToken)
{
var migrations = new List<PartitionMigration>();
foreach (var newAssignment in newAssignments)
{
var current = currentAssignments.FirstOrDefault(p => p.Id == newAssignment.Id);
if (current != null && current.NodeId != newAssignment.NodeId)
{
var migration = new PartitionMigration
{
PartitionId = newAssignment.Id,
SourceNodeId = current.NodeId,
TargetNodeId = newAssignment.NodeId,
Status = MigrationStatus.Pending
};
migrations.Add(migration);
// Execute migration
await ExecuteMigrationAsync(migration, cancellationToken);
}
}
return migrations;
}
private async Task ExecuteMigrationAsync(
PartitionMigration migration,
CancellationToken cancellationToken)
{
var message = new MigrationMessage
{
Type = MessageType.MigrationRequest,
Migration = migration
};
// Notify source node to prepare migration
await _messageBus.PublishAsync(
$"node.{migration.SourceNodeId}.migration",
message,
cancellationToken);
// Wait for migration completion
// Implementation depends on specific requirements
}
private async void RebalanceWorkloads(object? state)
{
if (!IsLeader)
return;
try
{
foreach (var workload in _workloads.Values)
{
await RebalanceWorkloadAsync(workload.Id);
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error during automatic rebalancing");
}
}
public void Dispose()
{
_rebalanceTimer?.Dispose();
_coordinationLock?.Dispose();
}
}
// Supporting classes and interfaces
public interface ISpaceTimeCoordinator : IDisposable
{
string NodeId { get; }
bool IsLeader { get; }
Task<PartitionAssignment> RequestPartitionAsync(
string workloadId,
long dataSize,
CancellationToken cancellationToken = default);
Task<CheckpointCoordination> CoordinateCheckpointAsync(
string workloadId,
string checkpointId,
CancellationToken cancellationToken = default);
Task<WorkloadStatistics> GetWorkloadStatisticsAsync(
string workloadId,
CancellationToken cancellationToken = default);
Task<RebalanceResult> RebalanceWorkloadAsync(
string workloadId,
CancellationToken cancellationToken = default);
}
public class CoordinatorOptions
{
public double RebalanceThreshold { get; set; } = 0.2; // 20% imbalance
public TimeSpan CheckpointTimeout { get; set; } = TimeSpan.FromMinutes(5);
public TimeSpan RebalanceInterval { get; set; } = TimeSpan.FromMinutes(5);
}
public class PartitionAssignment
{
public string WorkloadId { get; set; } = "";
public List<Partition> Partitions { get; set; } = new();
public PartitionStrategy Strategy { get; set; }
}
public class Partition
{
public string Id { get; set; } = "";
public string WorkloadId { get; set; } = "";
public string NodeId { get; set; } = "";
public long StartOffset { get; set; }
public long EndOffset { get; set; }
public PartitionStatus Status { get; set; }
}
public enum PartitionStatus
{
Assigned,
Active,
Migrating,
Completed,
Failed
}
public enum PartitionStrategy
{
SqrtN,
Linear,
Adaptive
}
public class CheckpointCoordination
{
public string CheckpointId { get; set; } = "";
public string WorkloadId { get; set; } = "";
public DateTime Timestamp { get; set; }
public CheckpointStatus Status { get; set; }
public List<CheckpointAck> NodeAcknowledgments { get; set; } = new();
}
public enum CheckpointStatus
{
InProgress,
Completed,
Failed
}
public class CheckpointAck
{
public string NodeId { get; set; } = "";
public string CheckpointId { get; set; } = "";
public bool Success { get; set; }
public string? Error { get; set; }
}
public class WorkloadStatistics
{
public string WorkloadId { get; set; } = "";
public long TotalDataSize { get; set; }
public long ProcessedSize { get; set; }
public long MemoryUsage { get; set; }
public int ActivePartitions { get; set; }
public int CompletedPartitions { get; set; }
public double AverageProcessingRate { get; set; }
public List<NodeStatistics> NodeStatistics { get; set; } = new();
}
public class NodeStatistics
{
public string NodeId { get; set; } = "";
public long ProcessedSize { get; set; }
public long MemoryUsage { get; set; }
public int ActivePartitions { get; set; }
public int CompletedPartitions { get; set; }
public double ProcessingRate { get; set; }
}
public class RebalanceResult
{
public string WorkloadId { get; set; } = "";
public bool RebalanceNeeded { get; set; }
public int MigratedPartitions { get; set; }
public double OldImbalance { get; set; }
public double NewImbalance { get; set; }
public string? Message { get; set; }
}
// Internal classes
internal class PartitionInfo
{
public Partition Partition { get; set; } = null!;
public DateTime AssignedAt { get; set; }
}
internal class WorkloadInfo
{
public string Id { get; set; } = "";
public long DataSize { get; set; }
public int RequestedPartitions { get; set; }
public DateTime CreatedAt { get; set; }
}
internal class PartitionMigration
{
public string PartitionId { get; set; } = "";
public string SourceNodeId { get; set; } = "";
public string TargetNodeId { get; set; } = "";
public MigrationStatus Status { get; set; }
}
internal enum MigrationStatus
{
Pending,
InProgress,
Completed,
Failed
}
// Message types
internal enum MessageType
{
PartitionAssignment,
CheckpointRequest,
MigrationRequest,
StatisticsRequest
}
internal class CheckpointMessage
{
public MessageType Type { get; set; }
public string CheckpointId { get; set; } = "";
public string WorkloadId { get; set; } = "";
}
internal class PartitionAssignmentMessage
{
public MessageType Type { get; set; }
public string NodeId { get; set; } = "";
public List<Partition> Partitions { get; set; } = new();
}
internal class MigrationMessage
{
public MessageType Type { get; set; }
public PartitionMigration Migration { get; set; } = null!;
}
internal class StatisticsRequest
{
public string WorkloadId { get; set; } = "";
public string NodeId { get; set; } = "";
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Distributed;
/// <summary>
/// Represents a node in the distributed SpaceTime system
/// </summary>
public class SpaceTimeNode : IHostedService, IDisposable
{
private readonly INodeRegistry _nodeRegistry;
private readonly IMessageBus _messageBus;
private readonly ILogger<SpaceTimeNode> _logger;
private readonly NodeOptions _options;
private readonly ConcurrentDictionary<string, WorkloadExecutor> _executors;
private readonly Timer _heartbeatTimer;
private readonly Timer _metricsTimer;
private readonly SemaphoreSlim _executorLock;
public string NodeId { get; }
public NodeInfo NodeInfo { get; private set; }
public SpaceTimeNode(
INodeRegistry nodeRegistry,
IMessageBus messageBus,
ILogger<SpaceTimeNode> logger,
NodeOptions? options = null)
{
_nodeRegistry = nodeRegistry ?? throw new ArgumentNullException(nameof(nodeRegistry));
_messageBus = messageBus ?? throw new ArgumentNullException(nameof(messageBus));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_options = options ?? new NodeOptions();
NodeId = _options.NodeId ?? Guid.NewGuid().ToString();
_executors = new ConcurrentDictionary<string, WorkloadExecutor>();
_executorLock = new SemaphoreSlim(1, 1);
NodeInfo = CreateNodeInfo();
_heartbeatTimer = new Timer(SendHeartbeat, null, Timeout.Infinite, Timeout.Infinite);
_metricsTimer = new Timer(CollectMetrics, null, Timeout.Infinite, Timeout.Infinite);
}
public async Task StartAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Starting SpaceTime node {NodeId}", NodeId);
// Register node
await _nodeRegistry.RegisterNodeAsync(NodeInfo, cancellationToken);
// Subscribe to messages
await SubscribeToMessagesAsync(cancellationToken);
// Start timers
_heartbeatTimer.Change(TimeSpan.Zero, _options.HeartbeatInterval);
_metricsTimer.Change(TimeSpan.Zero, _options.MetricsInterval);
_logger.LogInformation("SpaceTime node {NodeId} started successfully", NodeId);
}
public async Task StopAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Stopping SpaceTime node {NodeId}", NodeId);
// Stop timers
_heartbeatTimer.Change(Timeout.Infinite, Timeout.Infinite);
_metricsTimer.Change(Timeout.Infinite, Timeout.Infinite);
// Drain workloads
NodeInfo.Status = NodeStatus.Draining;
await _nodeRegistry.UpdateNodeHeartbeatAsync(NodeId, cancellationToken);
// Stop all executors
await StopAllExecutorsAsync(cancellationToken);
// Unregister node
await _nodeRegistry.UnregisterNodeAsync(NodeId, cancellationToken);
_logger.LogInformation("SpaceTime node {NodeId} stopped", NodeId);
}
public async Task<bool> AcceptPartitionAsync(Partition partition, CancellationToken cancellationToken = default)
{
await _executorLock.WaitAsync(cancellationToken);
try
{
// Check capacity
if (_executors.Count >= _options.MaxConcurrentWorkloads)
{
_logger.LogWarning("Node {NodeId} at capacity, rejecting partition {PartitionId}",
NodeId, partition.Id);
return false;
}
// Check memory
var estimatedMemory = EstimatePartitionMemory(partition);
if (GetAvailableMemory() < estimatedMemory)
{
_logger.LogWarning("Node {NodeId} insufficient memory for partition {PartitionId}",
NodeId, partition.Id);
return false;
}
// Create executor
var executor = new WorkloadExecutor(partition, _logger);
if (_executors.TryAdd(partition.Id, executor))
{
await executor.StartAsync(cancellationToken);
_logger.LogInformation("Node {NodeId} accepted partition {PartitionId}",
NodeId, partition.Id);
return true;
}
return false;
}
finally
{
_executorLock.Release();
}
}
public async Task<NodeStatistics> GetStatisticsAsync(string workloadId, CancellationToken cancellationToken = default)
{
var relevantExecutors = _executors.Values
.Where(e => e.Partition.WorkloadId == workloadId)
.ToList();
var stats = new NodeStatistics
{
NodeId = NodeId,
ProcessedSize = relevantExecutors.Sum(e => e.ProcessedBytes),
MemoryUsage = relevantExecutors.Sum(e => e.MemoryUsage),
ActivePartitions = relevantExecutors.Count(e => e.Status == ExecutorStatus.Running),
CompletedPartitions = relevantExecutors.Count(e => e.Status == ExecutorStatus.Completed),
ProcessingRate = relevantExecutors.Any()
? relevantExecutors.Average(e => e.ProcessingRate)
: 0
};
return stats;
}
private async Task SubscribeToMessagesAsync(CancellationToken cancellationToken)
{
// Subscribe to partition assignments
await _messageBus.SubscribeAsync<PartitionAssignmentMessage>(
$"node.{NodeId}.assignments",
async msg => await HandlePartitionAssignmentAsync(msg),
cancellationToken);
// Subscribe to checkpoint requests
await _messageBus.SubscribeAsync<CheckpointMessage>(
$"checkpoint.*",
async msg => await HandleCheckpointRequestAsync(msg),
cancellationToken);
// Subscribe to statistics requests
await _messageBus.SubscribeAsync<StatisticsRequest>(
$"node.{NodeId}.stats",
async req => await HandleStatisticsRequestAsync(req),
cancellationToken);
}
private async Task HandlePartitionAssignmentAsync(PartitionAssignmentMessage message)
{
foreach (var partition in message.Partitions)
{
await AcceptPartitionAsync(partition);
}
}
private async Task HandleCheckpointRequestAsync(CheckpointMessage message)
{
var relevantExecutors = _executors.Values
.Where(e => e.Partition.WorkloadId == message.WorkloadId)
.ToList();
var acks = new List<Task<CheckpointAck>>();
foreach (var executor in relevantExecutors)
{
acks.Add(executor.CreateCheckpointAsync(message.CheckpointId));
}
var results = await Task.WhenAll(acks);
// Send acknowledgments
foreach (var ack in results)
{
await _messageBus.PublishAsync(
$"checkpoint.{message.CheckpointId}.ack",
ack);
}
}
private async Task HandleStatisticsRequestAsync(StatisticsRequest request)
{
var stats = await GetStatisticsAsync(request.WorkloadId);
await _messageBus.PublishAsync($"node.{NodeId}.stats.response", stats);
}
private NodeInfo CreateNodeInfo()
{
return new NodeInfo
{
Id = NodeId,
Hostname = Environment.MachineName,
Port = _options.Port,
Capabilities = new NodeCapabilities
{
MaxMemory = _options.MaxMemory,
MaxConcurrentWorkloads = _options.MaxConcurrentWorkloads,
SupportedFeatures = new List<string>
{
"checkpointing",
"external-storage",
"compression"
}
},
Status = NodeStatus.Active,
LastHeartbeat = DateTime.UtcNow,
CurrentLoad = 0,
AvailableMemory = _options.MaxMemory
};
}
private async void SendHeartbeat(object? state)
{
try
{
NodeInfo.LastHeartbeat = DateTime.UtcNow;
NodeInfo.CurrentLoad = CalculateCurrentLoad();
NodeInfo.AvailableMemory = GetAvailableMemory();
await _nodeRegistry.UpdateNodeHeartbeatAsync(NodeId);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error sending heartbeat for node {NodeId}", NodeId);
}
}
private void CollectMetrics(object? state)
{
try
{
var metrics = new NodeMetrics
{
NodeId = NodeId,
Timestamp = DateTime.UtcNow,
ActiveWorkloads = _executors.Count,
TotalProcessedBytes = _executors.Values.Sum(e => e.ProcessedBytes),
AverageProcessingRate = _executors.Values.Any()
? _executors.Values.Average(e => e.ProcessingRate)
: 0,
MemoryUsage = _executors.Values.Sum(e => e.MemoryUsage),
CpuUsage = GetCpuUsage()
};
// Publish metrics
_messageBus.PublishAsync($"metrics.node.{NodeId}", metrics).Wait();
}
catch (Exception ex)
{
_logger.LogError(ex, "Error collecting metrics for node {NodeId}", NodeId);
}
}
private double CalculateCurrentLoad()
{
if (_options.MaxConcurrentWorkloads == 0)
return 0;
return (double)_executors.Count / _options.MaxConcurrentWorkloads;
}
private long GetAvailableMemory()
{
var usedMemory = _executors.Values.Sum(e => e.MemoryUsage);
return Math.Max(0, _options.MaxMemory - usedMemory);
}
private long EstimatePartitionMemory(Partition partition)
{
var dataSize = partition.EndOffset - partition.StartOffset;
// Use √n estimation
return SpaceTimeCalculator.CalculateSqrtInterval(dataSize) * 1024; // Rough estimate
}
private double GetCpuUsage()
{
// Simplified CPU usage calculation
return Environment.ProcessorCount > 0
? (double)Environment.TickCount / Environment.ProcessorCount / 1000
: 0;
}
private async Task StopAllExecutorsAsync(CancellationToken cancellationToken)
{
var tasks = _executors.Values.Select(e => e.StopAsync(cancellationToken));
await Task.WhenAll(tasks);
_executors.Clear();
}
public void Dispose()
{
_heartbeatTimer?.Dispose();
_metricsTimer?.Dispose();
_executorLock?.Dispose();
foreach (var executor in _executors.Values)
{
executor.Dispose();
}
}
}
public class NodeOptions
{
public string? NodeId { get; set; }
public int Port { get; set; } = 5000;
public long MaxMemory { get; set; } = 4L * 1024 * 1024 * 1024; // 4GB
public int MaxConcurrentWorkloads { get; set; } = 10;
public TimeSpan HeartbeatInterval { get; set; } = TimeSpan.FromSeconds(30);
public TimeSpan MetricsInterval { get; set; } = TimeSpan.FromMinutes(1);
}
internal class WorkloadExecutor : IDisposable
{
private readonly ILogger _logger;
private readonly CancellationTokenSource _cts;
private Task? _executionTask;
public Partition Partition { get; }
public ExecutorStatus Status { get; private set; }
public long ProcessedBytes { get; private set; }
public long MemoryUsage { get; private set; }
public double ProcessingRate { get; private set; }
public WorkloadExecutor(Partition partition, ILogger logger)
{
Partition = partition;
_logger = logger;
_cts = new CancellationTokenSource();
Status = ExecutorStatus.Created;
}
public async Task StartAsync(CancellationToken cancellationToken = default)
{
Status = ExecutorStatus.Running;
_executionTask = Task.Run(() => ExecuteWorkloadAsync(_cts.Token), cancellationToken);
}
public async Task StopAsync(CancellationToken cancellationToken = default)
{
_cts.Cancel();
if (_executionTask != null)
{
await _executionTask;
}
Status = ExecutorStatus.Stopped;
}
public async Task<CheckpointAck> CreateCheckpointAsync(string checkpointId)
{
try
{
// Create checkpoint
var checkpoint = new
{
PartitionId = Partition.Id,
ProcessedBytes = ProcessedBytes,
Timestamp = DateTime.UtcNow
};
// Save checkpoint (implementation depends on storage)
await Task.Delay(100); // Simulate checkpoint creation
return new CheckpointAck
{
NodeId = Partition.NodeId,
CheckpointId = checkpointId,
Success = true
};
}
catch (Exception ex)
{
return new CheckpointAck
{
NodeId = Partition.NodeId,
CheckpointId = checkpointId,
Success = false,
Error = ex.Message
};
}
}
private async Task ExecuteWorkloadAsync(CancellationToken cancellationToken)
{
var startTime = DateTime.UtcNow;
var dataSize = Partition.EndOffset - Partition.StartOffset;
// Simulate workload execution
while (ProcessedBytes < dataSize && !cancellationToken.IsCancellationRequested)
{
// Process in √n chunks
var chunkSize = SpaceTimeCalculator.CalculateSqrtInterval(dataSize);
var toProcess = Math.Min(chunkSize, dataSize - ProcessedBytes);
// Simulate processing
await Task.Delay(100, cancellationToken);
ProcessedBytes += toProcess;
MemoryUsage = SpaceTimeCalculator.CalculateSqrtInterval(ProcessedBytes) * 1024;
var elapsed = (DateTime.UtcNow - startTime).TotalSeconds;
ProcessingRate = elapsed > 0 ? ProcessedBytes / elapsed : 0;
}
Status = cancellationToken.IsCancellationRequested
? ExecutorStatus.Cancelled
: ExecutorStatus.Completed;
}
public void Dispose()
{
_cts?.Cancel();
_cts?.Dispose();
_executionTask?.Wait(TimeSpan.FromSeconds(5));
}
}
internal enum ExecutorStatus
{
Created,
Running,
Completed,
Cancelled,
Stopped,
Failed
}
internal class NodeMetrics
{
public string NodeId { get; set; } = "";
public DateTime Timestamp { get; set; }
public int ActiveWorkloads { get; set; }
public long TotalProcessedBytes { get; set; }
public double AverageProcessingRate { get; set; }
public long MemoryUsage { get; set; }
public double CpuUsage { get; set; }
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Distributed coordination and execution for SpaceTime operations</Description>
<PackageTags>distributed;coordination;spacetime;partitioning;clustering</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Distributed</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Infrastructure;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.EntityFramework;
/// <summary>
/// Factory for creating SpaceTime-optimized change trackers
/// </summary>
internal interface IChangeTrackerFactory
{
ChangeTracker CreateChangeTracker(DbContext context);
}
/// <summary>
/// Implementation of SpaceTime change tracker factory
/// </summary>
internal class SpaceTimeChangeTrackerFactory : IChangeTrackerFactory
{
private readonly SpaceTimeOptions _options;
public SpaceTimeChangeTrackerFactory(SpaceTimeOptions options)
{
_options = options;
}
public ChangeTracker CreateChangeTracker(DbContext context)
{
// In practice, we'd need to hook into EF Core's internal change tracking
// For now, return the standard change tracker with optimizations applied
var changeTracker = context.ChangeTracker;
if (_options.EnableSqrtNChangeTracking)
{
ConfigureSqrtNTracking(changeTracker);
}
return changeTracker;
}
private void ConfigureSqrtNTracking(ChangeTracker changeTracker)
{
// Configure change tracker for √n memory usage
changeTracker.AutoDetectChangesEnabled = false;
changeTracker.LazyLoadingEnabled = false;
changeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTrackingWithIdentityResolution;
}
}
/// <summary>
/// Query processor with SpaceTime optimizations
/// </summary>
internal interface IQueryProcessor
{
IQueryable<T> OptimizeQuery<T>(IQueryable<T> query) where T : class;
Task<List<T>> ExecuteOptimizedAsync<T>(IQueryable<T> query, CancellationToken cancellationToken = default) where T : class;
}
/// <summary>
/// Implementation of SpaceTime query processor
/// </summary>
internal class SpaceTimeQueryProcessor : IQueryProcessor
{
private readonly SpaceTimeOptions _options;
private readonly CheckpointManager? _checkpointManager;
public SpaceTimeQueryProcessor(SpaceTimeOptions options)
{
_options = options;
if (_options.EnableQueryCheckpointing)
{
_checkpointManager = new CheckpointManager(_options.CheckpointDirectory);
}
}
public IQueryable<T> OptimizeQuery<T>(IQueryable<T> query) where T : class
{
// Apply optimizations to the query
if (_options.EnableBatchSizeOptimization)
{
// This would need integration with the query provider
// For demonstration, we'll just return the query
}
return query;
}
public async Task<List<T>> ExecuteOptimizedAsync<T>(IQueryable<T> query, CancellationToken cancellationToken = default) where T : class
{
if (_checkpointManager != null)
{
// Try to restore from checkpoint
var checkpoint = await _checkpointManager.RestoreLatestCheckpointAsync<List<T>>();
if (checkpoint != null)
{
return checkpoint;
}
}
var results = new List<T>();
var batchSize = _options.MaxTrackedEntities ?? SpaceTimeCalculator.CalculateSqrtInterval(10000);
// Execute in batches
var processed = 0;
while (true)
{
var batch = await query
.Skip(processed)
.Take(batchSize)
.ToListAsync(cancellationToken);
if (!batch.Any())
break;
results.AddRange(batch);
processed += batch.Count;
// Checkpoint if needed
if (_checkpointManager != null && _checkpointManager.ShouldCheckpoint())
{
await _checkpointManager.CreateCheckpointAsync(results);
}
}
return results;
}
}
/// <summary>
/// Extension methods for SpaceTime query optimization
/// </summary>
public static class SpaceTimeQueryableExtensions
{
/// <summary>
/// Executes the query with √n memory optimization
/// </summary>
public static async Task<List<T>> ToListWithSqrtNMemoryAsync<T>(
this IQueryable<T> query,
CancellationToken cancellationToken = default) where T : class
{
var context = GetDbContext(query);
if (context == null)
{
return await query.ToListAsync(cancellationToken);
}
var processor = context.GetService<IQueryProcessor>();
if (processor == null)
{
return await query.ToListAsync(cancellationToken);
}
return await processor.ExecuteOptimizedAsync(query, cancellationToken);
}
/// <summary>
/// Applies no-tracking with √n identity resolution
/// </summary>
public static IQueryable<T> AsNoTrackingWithSqrtNIdentityResolution<T>(this IQueryable<T> query) where T : class
{
return query.AsNoTrackingWithIdentityResolution();
}
private static DbContext? GetDbContext<T>(IQueryable<T> query)
{
var provider = query.Provider;
var contextProperty = provider.GetType().GetProperty("Context");
return contextProperty?.GetValue(provider) as DbContext;
}
}

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using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.Extensions.DependencyInjection;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.EntityFramework;
/// <summary>
/// Extension methods for configuring SpaceTime optimizations in Entity Framework Core
/// </summary>
public static class SpaceTimeDbContextOptionsExtensions
{
/// <summary>
/// Configures the context to use SpaceTime optimizations
/// </summary>
public static DbContextOptionsBuilder UseSpaceTimeOptimizer(
this DbContextOptionsBuilder optionsBuilder,
Action<SpaceTimeOptions>? configureOptions = null)
{
var options = new SpaceTimeOptions();
configureOptions?.Invoke(options);
var extension = new SpaceTimeOptionsExtension(options);
((IDbContextOptionsBuilderInfrastructure)optionsBuilder).AddOrUpdateExtension(extension);
return optionsBuilder;
}
/// <summary>
/// Configures the context to use SpaceTime optimizations
/// </summary>
public static DbContextOptionsBuilder<TContext> UseSpaceTimeOptimizer<TContext>(
this DbContextOptionsBuilder<TContext> optionsBuilder,
Action<SpaceTimeOptions>? configureOptions = null) where TContext : DbContext
{
return (DbContextOptionsBuilder<TContext>)UseSpaceTimeOptimizer(
(DbContextOptionsBuilder)optionsBuilder, configureOptions);
}
}
/// <summary>
/// Options for SpaceTime optimizations
/// </summary>
public class SpaceTimeOptions
{
/// <summary>
/// Enable √n change tracking optimization
/// </summary>
public bool EnableSqrtNChangeTracking { get; set; } = true;
/// <summary>
/// Enable query result checkpointing
/// </summary>
public bool EnableQueryCheckpointing { get; set; } = true;
/// <summary>
/// Maximum entities to track before spilling to external storage
/// </summary>
public int? MaxTrackedEntities { get; set; }
/// <summary>
/// Buffer pool strategy
/// </summary>
public BufferPoolStrategy BufferPoolStrategy { get; set; } = BufferPoolStrategy.SqrtN;
/// <summary>
/// Checkpoint directory for query results
/// </summary>
public string? CheckpointDirectory { get; set; }
/// <summary>
/// Enable automatic batch size optimization
/// </summary>
public bool EnableBatchSizeOptimization { get; set; } = true;
}
/// <summary>
/// Buffer pool strategies
/// </summary>
public enum BufferPoolStrategy
{
/// <summary>Default EF Core behavior</summary>
Default,
/// <summary>Use √n of available memory</summary>
SqrtN,
/// <summary>Fixed size buffer pool</summary>
Fixed,
/// <summary>Adaptive based on workload</summary>
Adaptive
}
/// <summary>
/// Internal extension for EF Core
/// </summary>
internal class SpaceTimeOptionsExtension : IDbContextOptionsExtension
{
private readonly SpaceTimeOptions _options;
private DbContextOptionsExtensionInfo? _info;
public SpaceTimeOptionsExtension(SpaceTimeOptions options)
{
_options = options;
}
public DbContextOptionsExtensionInfo Info => _info ??= new ExtensionInfo(this);
public void ApplyServices(IServiceCollection services)
{
services.AddSingleton(_options);
services.AddScoped<IChangeTrackerFactory, SpaceTimeChangeTrackerFactory>();
services.AddScoped<IQueryProcessor, SpaceTimeQueryProcessor>();
}
public void Validate(IDbContextOptions options)
{
// Validation logic if needed
}
private sealed class ExtensionInfo : DbContextOptionsExtensionInfo
{
private readonly SpaceTimeOptionsExtension _extension;
public ExtensionInfo(SpaceTimeOptionsExtension extension) : base(extension)
{
_extension = extension;
}
public override bool IsDatabaseProvider => false;
public override string LogFragment => "SpaceTimeOptimizer";
public override int GetServiceProviderHashCode() => _extension._options.GetHashCode();
public override void PopulateDebugInfo(IDictionary<string, string> debugInfo)
{
debugInfo["SpaceTime:SqrtNChangeTracking"] = _extension._options.EnableSqrtNChangeTracking.ToString();
debugInfo["SpaceTime:QueryCheckpointing"] = _extension._options.EnableQueryCheckpointing.ToString();
}
public override bool ShouldUseSameServiceProvider(DbContextOptionsExtensionInfo other)
{
return other is ExtensionInfo;
}
}
}

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using System.Linq.Expressions;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Query;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.EntityFramework;
/// <summary>
/// Extended query extensions for SpaceTime optimizations
/// </summary>
public static class SpaceTimeQueryExtensions
{
/// <summary>
/// Configures the query to use external sorting for large datasets
/// </summary>
public static IQueryable<T> UseExternalSorting<T>(this IQueryable<T> query) where T : class
{
// Mark the query for external sorting
return query.TagWith("SpaceTime:UseExternalSorting");
}
/// <summary>
/// Streams query results asynchronously for memory efficiency
/// </summary>
public static async IAsyncEnumerable<T> StreamQueryResultsAsync<T>(
this IQueryable<T> query,
[System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default) where T : class
{
var context = GetDbContext(query);
if (context == null)
{
// Fallback to regular async enumeration
await foreach (var item in query.AsAsyncEnumerable().WithCancellation(cancellationToken))
{
yield return item;
}
yield break;
}
// Get total count for batch size calculation
var totalCount = await query.CountAsync(cancellationToken);
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
// Stream in batches
for (int offset = 0; offset < totalCount; offset += batchSize)
{
var batch = await query
.Skip(offset)
.Take(batchSize)
.ToListAsync(cancellationToken);
foreach (var item in batch)
{
yield return item;
}
// Clear change tracker to prevent memory buildup
context.ChangeTracker.Clear();
}
}
/// <summary>
/// Processes query results in √n-sized batches with checkpoint support
/// </summary>
public static async IAsyncEnumerable<IReadOnlyList<T>> BatchBySqrtNAsync<T>(
this IQueryable<T> query,
string? checkpointId = null,
bool resumeFromCheckpoint = false,
[System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default) where T : class
{
var context = GetDbContext(query);
var options = context?.GetService<SpaceTimeOptions>();
CheckpointManager? checkpointManager = null;
if (!string.IsNullOrEmpty(checkpointId) && options?.EnableQueryCheckpointing == true)
{
checkpointManager = new CheckpointManager(options.CheckpointDirectory);
}
try
{
var totalCount = await query.CountAsync(cancellationToken);
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
var startOffset = 0;
// Resume from checkpoint if requested
if (resumeFromCheckpoint && checkpointManager != null)
{
var checkpoint = await checkpointManager.RestoreCheckpointAsync<QueryCheckpoint>(checkpointId!);
if (checkpoint != null)
{
startOffset = checkpoint.ProcessedCount;
}
}
for (int offset = startOffset; offset < totalCount; offset += batchSize)
{
var batch = await query
.Skip(offset)
.Take(batchSize)
.ToListAsync(cancellationToken);
if (batch.Count == 0)
yield break;
yield return batch;
// Save checkpoint
if (checkpointManager != null && !string.IsNullOrEmpty(checkpointId))
{
await checkpointManager.CreateCheckpointAsync(new QueryCheckpoint
{
ProcessedCount = offset + batch.Count,
TotalCount = totalCount
}, checkpointId);
}
// Clear change tracker if enabled
if (context != null && options?.EnableSqrtNChangeTracking == true)
{
var trackedCount = context.ChangeTracker.Entries().Count();
if (trackedCount > (options.MaxTrackedEntities ?? batchSize))
{
context.ChangeTracker.Clear();
}
}
}
}
finally
{
checkpointManager?.Dispose();
}
}
private static DbContext? GetDbContext<T>(IQueryable<T> query)
{
if (query.Provider is IInfrastructure<IServiceProvider> infrastructure)
{
var context = infrastructure.Instance.GetService(typeof(DbContext)) as DbContext;
return context;
}
// Fallback: try reflection
var provider = query.Provider;
var contextProperty = provider.GetType().GetProperty("Context");
return contextProperty?.GetValue(provider) as DbContext;
}
private class QueryCheckpoint
{
public int ProcessedCount { get; set; }
public int TotalCount { get; set; }
}
}
/// <summary>
/// Extension methods for DbContext bulk operations
/// </summary>
public static class SpaceTimeDbContextExtensions
{
/// <summary>
/// Performs bulk insert with √n buffering for memory efficiency
/// </summary>
public static async Task BulkInsertWithSqrtNBufferingAsync<T>(
this DbContext context,
IEnumerable<T> entities,
CancellationToken cancellationToken = default) where T : class
{
ArgumentNullException.ThrowIfNull(context);
ArgumentNullException.ThrowIfNull(entities);
var options = context.GetService<SpaceTimeOptions>();
var entityList = entities as IList<T> ?? entities.ToList();
var totalCount = entityList.Count;
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
// Disable auto-detect changes for performance
var originalAutoDetectChanges = context.ChangeTracker.AutoDetectChangesEnabled;
context.ChangeTracker.AutoDetectChangesEnabled = false;
try
{
for (int i = 0; i < totalCount; i += batchSize)
{
var batch = entityList.Skip(i).Take(batchSize);
await context.AddRangeAsync(batch, cancellationToken);
await context.SaveChangesAsync(cancellationToken);
// Clear change tracker after each batch to prevent memory buildup
context.ChangeTracker.Clear();
}
}
finally
{
context.ChangeTracker.AutoDetectChangesEnabled = originalAutoDetectChanges;
}
}
/// <summary>
/// Performs bulk update with √n buffering for memory efficiency
/// </summary>
public static async Task BulkUpdateWithSqrtNBufferingAsync<T>(
this DbContext context,
IEnumerable<T> entities,
CancellationToken cancellationToken = default) where T : class
{
ArgumentNullException.ThrowIfNull(context);
ArgumentNullException.ThrowIfNull(entities);
var entityList = entities as IList<T> ?? entities.ToList();
var totalCount = entityList.Count;
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
// Disable auto-detect changes for performance
var originalAutoDetectChanges = context.ChangeTracker.AutoDetectChangesEnabled;
context.ChangeTracker.AutoDetectChangesEnabled = false;
try
{
for (int i = 0; i < totalCount; i += batchSize)
{
var batch = entityList.Skip(i).Take(batchSize);
context.UpdateRange(batch);
await context.SaveChangesAsync(cancellationToken);
// Clear change tracker after each batch
context.ChangeTracker.Clear();
}
}
finally
{
context.ChangeTracker.AutoDetectChangesEnabled = originalAutoDetectChanges;
}
}
/// <summary>
/// Performs bulk delete with √n buffering for memory efficiency
/// </summary>
public static async Task BulkDeleteWithSqrtNBufferingAsync<T>(
this DbContext context,
IEnumerable<T> entities,
CancellationToken cancellationToken = default) where T : class
{
ArgumentNullException.ThrowIfNull(context);
ArgumentNullException.ThrowIfNull(entities);
var entityList = entities as IList<T> ?? entities.ToList();
var totalCount = entityList.Count;
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
// Disable auto-detect changes for performance
var originalAutoDetectChanges = context.ChangeTracker.AutoDetectChangesEnabled;
context.ChangeTracker.AutoDetectChangesEnabled = false;
try
{
for (int i = 0; i < totalCount; i += batchSize)
{
var batch = entityList.Skip(i).Take(batchSize);
context.RemoveRange(batch);
await context.SaveChangesAsync(cancellationToken);
// Clear change tracker after each batch
context.ChangeTracker.Clear();
}
}
finally
{
context.ChangeTracker.AutoDetectChangesEnabled = originalAutoDetectChanges;
}
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Entity Framework Core optimizations using √n space-time tradeoffs</Description>
<PackageId>SqrtSpace.SpaceTime.EntityFramework</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.7" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.7" />
</ItemGroup>
</Project>

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using System.Collections;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Linq;
/// <summary>
/// External distinct implementation with limited memory
/// </summary>
internal sealed class ExternalDistinct<T> : IEnumerable<T> where T : notnull
{
private readonly IEnumerable<T> _source;
private readonly IEqualityComparer<T> _comparer;
private readonly int _maxMemoryItems;
public ExternalDistinct(IEnumerable<T> source, IEqualityComparer<T>? comparer, int maxMemoryItems)
{
_source = source;
_comparer = comparer ?? EqualityComparer<T>.Default;
_maxMemoryItems = maxMemoryItems;
}
public IEnumerator<T> GetEnumerator()
{
using var storage = new ExternalStorage<T>();
var seen = new HashSet<T>(_comparer);
var spillFiles = new List<string>();
foreach (var item in _source)
{
if (seen.Count >= _maxMemoryItems)
{
// Spill to disk and clear memory
var spillFile = storage.SpillToDiskAsync(seen).GetAwaiter().GetResult();
spillFiles.Add(spillFile);
seen.Clear();
}
if (seen.Add(item))
{
// Check if item exists in any spill file
var existsInSpillFile = false;
foreach (var spillFile in spillFiles)
{
foreach (var spilledItem in storage.ReadFromDiskAsync(spillFile).ToBlockingEnumerable())
{
if (_comparer.Equals(item, spilledItem))
{
existsInSpillFile = true;
break;
}
}
if (existsInSpillFile) break;
}
if (!existsInSpillFile)
{
yield return item;
}
}
}
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}
/// <summary>
/// Extension methods for async enumerable operations
/// </summary>
internal static class AsyncEnumerableExtensions
{
/// <summary>
/// Converts async enumerable to blocking enumerable for compatibility
/// </summary>
public static IEnumerable<T> ToBlockingEnumerable<T>(this IAsyncEnumerable<T> source)
{
var enumerator = source.GetAsyncEnumerator();
try
{
while (enumerator.MoveNextAsync().AsTask().GetAwaiter().GetResult())
{
yield return enumerator.Current;
}
}
finally
{
enumerator.DisposeAsync().AsTask().GetAwaiter().GetResult();
}
}
}

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using System.Collections;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Linq;
/// <summary>
/// External grouping implementation for large datasets
/// </summary>
internal sealed class ExternalGrouping<TSource, TKey> : IEnumerable<IGrouping<TKey, TSource>> where TKey : notnull
{
private readonly IEnumerable<TSource> _source;
private readonly Func<TSource, TKey> _keySelector;
private readonly IEqualityComparer<TKey> _comparer;
private readonly int _bufferSize;
public ExternalGrouping(
IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IEqualityComparer<TKey>? comparer,
int bufferSize)
{
_source = source;
_keySelector = keySelector;
_comparer = comparer ?? EqualityComparer<TKey>.Default;
_bufferSize = bufferSize;
}
public IEnumerator<IGrouping<TKey, TSource>> GetEnumerator()
{
using var storage = new ExternalStorage<KeyValuePair<TKey, TSource>>();
var groups = new Dictionary<TKey, List<TSource>>(_comparer);
var spilledKeys = new Dictionary<TKey, string>(_comparer);
// Process source
foreach (var item in _source)
{
var key = _keySelector(item);
if (!groups.ContainsKey(key))
{
if (groups.Count >= _bufferSize)
{
// Spill largest group to disk
SpillLargestGroup(groups, spilledKeys, storage);
}
groups[key] = new List<TSource>();
}
groups[key].Add(item);
}
// Yield in-memory groups
foreach (var kvp in groups)
{
yield return new Grouping<TKey, TSource>(kvp.Key, kvp.Value);
}
// Yield spilled groups
foreach (var kvp in spilledKeys)
{
var items = new List<TSource>();
foreach (var pair in storage.ReadFromDiskAsync(kvp.Value).ToBlockingEnumerable())
{
if (_comparer.Equals(pair.Key, kvp.Key))
{
items.Add(pair.Value);
}
}
yield return new Grouping<TKey, TSource>(kvp.Key, items);
}
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
private void SpillLargestGroup(
Dictionary<TKey, List<TSource>> groups,
Dictionary<TKey, string> spilledKeys,
ExternalStorage<KeyValuePair<TKey, TSource>> storage)
{
// Find largest group
var largest = groups.OrderByDescending(g => g.Value.Count).First();
// Convert to key-value pairs for storage
var pairs = largest.Value.Select(v => new KeyValuePair<TKey, TSource>(largest.Key, v));
// Spill to disk
var spillFile = storage.SpillToDiskAsync(pairs).GetAwaiter().GetResult();
spilledKeys[largest.Key] = spillFile;
// Remove from memory
groups.Remove(largest.Key);
}
}
/// <summary>
/// Represents a group of elements with a common key
/// </summary>
internal sealed class Grouping<TKey, TElement> : IGrouping<TKey, TElement>
{
private readonly IEnumerable<TElement> _elements;
public Grouping(TKey key, IEnumerable<TElement> elements)
{
Key = key;
_elements = elements;
}
public TKey Key { get; }
public IEnumerator<TElement> GetEnumerator() => _elements.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

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using System.Collections;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Linq;
/// <summary>
/// External merge sort implementation for large datasets
/// </summary>
internal sealed class ExternalOrderedEnumerable<TSource, TKey> : IOrderedEnumerable<TSource> where TKey : notnull
{
private readonly IEnumerable<TSource> _source;
private readonly Func<TSource, TKey> _keySelector;
private readonly IComparer<TKey> _comparer;
private readonly int _bufferSize;
public ExternalOrderedEnumerable(
IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey>? comparer,
int? bufferSize)
{
_source = source;
_keySelector = keySelector;
_comparer = comparer ?? Comparer<TKey>.Default;
var count = source.TryGetNonEnumeratedCount(out var c) ? c : 100_000;
_bufferSize = bufferSize ?? SpaceTimeCalculator.CalculateSqrtInterval(count);
}
public IOrderedEnumerable<TSource> CreateOrderedEnumerable<TNewKey>(
Func<TSource, TNewKey> keySelector,
IComparer<TNewKey>? comparer,
bool descending)
{
// Create secondary sort key
return new ThenByOrderedEnumerable<TSource, TKey, TNewKey>(
this, keySelector, comparer, descending);
}
public IEnumerator<TSource> GetEnumerator()
{
// External merge sort implementation
using var storage = new ExternalStorage<TSource>();
var chunks = new List<string>();
var chunk = new List<TSource>(_bufferSize);
// Phase 1: Sort chunks and spill to disk
foreach (var item in _source)
{
chunk.Add(item);
if (chunk.Count >= _bufferSize)
{
var sortedChunk = chunk.OrderBy(_keySelector, _comparer).ToList();
var spillFile = storage.SpillToDiskAsync(sortedChunk).GetAwaiter().GetResult();
chunks.Add(spillFile);
chunk.Clear();
}
}
// Sort and spill remaining items
if (chunk.Count > 0)
{
var sortedChunk = chunk.OrderBy(_keySelector, _comparer).ToList();
var spillFile = storage.SpillToDiskAsync(sortedChunk).GetAwaiter().GetResult();
chunks.Add(spillFile);
}
// Phase 2: Merge sorted chunks
if (chunks.Count == 0)
yield break;
if (chunks.Count == 1)
{
// Single chunk, just read it back
foreach (var item in storage.ReadFromDiskAsync(chunks[0]).ToBlockingEnumerable())
{
yield return item;
}
}
else
{
// Multi-way merge
var iterators = new List<IEnumerator<TSource>>();
var heap = new SortedDictionary<(TKey key, int index), (TSource item, int streamIndex)>(
new MergeComparer<TKey>(_comparer));
try
{
// Initialize iterators
for (int i = 0; i < chunks.Count; i++)
{
var iterator = storage.ReadFromDiskAsync(chunks[i]).ToBlockingEnumerable().GetEnumerator();
iterators.Add(iterator);
if (iterator.MoveNext())
{
var item = iterator.Current;
var key = _keySelector(item);
heap.Add((key, i), (item, i));
}
}
// Merge
while (heap.Count > 0)
{
var min = heap.First();
yield return min.Value.item;
heap.Remove(min.Key);
var streamIndex = min.Value.streamIndex;
if (iterators[streamIndex].MoveNext())
{
var item = iterators[streamIndex].Current;
var key = _keySelector(item);
heap.Add((key, streamIndex), (item, streamIndex));
}
}
}
finally
{
foreach (var iterator in iterators)
{
iterator.Dispose();
}
}
}
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
private sealed class MergeComparer<T> : IComparer<(T key, int index)>
{
private readonly IComparer<T> _keyComparer;
public MergeComparer(IComparer<T> keyComparer)
{
_keyComparer = keyComparer;
}
public int Compare((T key, int index) x, (T key, int index) y)
{
var keyComparison = _keyComparer.Compare(x.key, y.key);
return keyComparison != 0 ? keyComparison : x.index.CompareTo(y.index);
}
}
}
/// <summary>
/// Secondary ordering for ThenBy operations
/// </summary>
internal sealed class ThenByOrderedEnumerable<TSource, TPrimaryKey, TSecondaryKey> : IOrderedEnumerable<TSource>
{
private readonly IOrderedEnumerable<TSource> _primary;
private readonly Func<TSource, TSecondaryKey> _keySelector;
private readonly IComparer<TSecondaryKey> _comparer;
private readonly bool _descending;
public ThenByOrderedEnumerable(
IOrderedEnumerable<TSource> primary,
Func<TSource, TSecondaryKey> keySelector,
IComparer<TSecondaryKey>? comparer,
bool descending)
{
_primary = primary;
_keySelector = keySelector;
_comparer = comparer ?? Comparer<TSecondaryKey>.Default;
_descending = descending;
}
public IOrderedEnumerable<TSource> CreateOrderedEnumerable<TNewKey>(
Func<TSource, TNewKey> keySelector,
IComparer<TNewKey>? comparer,
bool descending)
{
return new ThenByOrderedEnumerable<TSource, TSecondaryKey, TNewKey>(
this, keySelector, comparer, descending);
}
public IEnumerator<TSource> GetEnumerator()
{
// For simplicity, materialize and use standard LINQ
// A production implementation would merge this into the external sort
var items = _primary.ToList();
var ordered = _descending
? items.OrderByDescending(_keySelector, _comparer)
: items.OrderBy(_keySelector, _comparer);
foreach (var item in ordered)
{
yield return item;
}
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

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using System.Collections;
using System.Text.Json;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Linq;
/// <summary>
/// LINQ extensions that implement space-time tradeoffs for memory-efficient operations
/// </summary>
public static class SpaceTimeEnumerable
{
/// <summary>
/// Orders a sequence using external merge sort with √n memory usage
/// </summary>
public static IOrderedEnumerable<TSource> OrderByExternal<TSource, TKey>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey>? comparer = null,
int? bufferSize = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
return new ExternalOrderedEnumerable<TSource, TKey>(source, keySelector, comparer, bufferSize);
}
/// <summary>
/// Orders a sequence in descending order using external merge sort
/// </summary>
public static IOrderedEnumerable<TSource> OrderByDescendingExternal<TSource, TKey>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey>? comparer = null,
int? bufferSize = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
var reverseComparer = new ReverseComparer<TKey>(comparer ?? Comparer<TKey>.Default);
return new ExternalOrderedEnumerable<TSource, TKey>(source, keySelector, reverseComparer, bufferSize);
}
/// <summary>
/// Performs a subsequent ordering on an already ordered sequence
/// </summary>
public static IOrderedEnumerable<TSource> ThenByExternal<TSource, TKey>(
this IOrderedEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey>? comparer = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
return source.CreateOrderedEnumerable(keySelector, comparer, false);
}
/// <summary>
/// Performs a subsequent descending ordering on an already ordered sequence
/// </summary>
public static IOrderedEnumerable<TSource> ThenByDescendingExternal<TSource, TKey>(
this IOrderedEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey>? comparer = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
return source.CreateOrderedEnumerable(keySelector, comparer, true);
}
/// <summary>
/// Groups elements using √n memory for large datasets
/// </summary>
public static IEnumerable<IGrouping<TKey, TSource>> GroupByExternal<TSource, TKey>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IEqualityComparer<TKey>? comparer = null,
int? bufferSize = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
var count = source.TryGetNonEnumeratedCount(out var c) ? c : 1_000_000;
var optimalBuffer = bufferSize ?? SpaceTimeCalculator.CalculateSqrtInterval(count);
return new ExternalGrouping<TSource, TKey>(source, keySelector, comparer, optimalBuffer);
}
/// <summary>
/// Groups elements with element projection using √n memory for large datasets
/// </summary>
public static IEnumerable<IGrouping<TKey, TElement>> GroupByExternal<TSource, TKey, TElement>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
Func<TSource, TElement> elementSelector,
IEqualityComparer<TKey>? comparer = null,
int? bufferSize = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
ArgumentNullException.ThrowIfNull(elementSelector);
var projected = source.Select(x => new { Key = keySelector(x), Element = elementSelector(x) });
var count = source.TryGetNonEnumeratedCount(out var c) ? c : 1_000_000;
var optimalBuffer = bufferSize ?? SpaceTimeCalculator.CalculateSqrtInterval(count);
return new ExternalGrouping<dynamic, TKey>(projected, x => x.Key, comparer, optimalBuffer)
.Select(g => new Grouping<TKey, TElement>(g.Key, g.Select(x => (TElement)x.Element)));
}
/// <summary>
/// Groups elements with result projection using √n memory for large datasets
/// </summary>
public static IEnumerable<TResult> GroupByExternal<TSource, TKey, TElement, TResult>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
Func<TSource, TElement> elementSelector,
Func<TKey, IEnumerable<TElement>, TResult> resultSelector,
IEqualityComparer<TKey>? comparer = null,
int? bufferSize = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(keySelector);
ArgumentNullException.ThrowIfNull(elementSelector);
ArgumentNullException.ThrowIfNull(resultSelector);
return GroupByExternal(source, keySelector, elementSelector, comparer, bufferSize)
.Select(g => resultSelector(g.Key, g));
}
/// <summary>
/// Processes sequence in √n-sized batches for memory efficiency
/// </summary>
public static IEnumerable<IReadOnlyList<T>> BatchBySqrtN<T>(
this IEnumerable<T> source,
int? totalCount = null)
{
ArgumentNullException.ThrowIfNull(source);
var count = totalCount ?? (source.TryGetNonEnumeratedCount(out var c) ? c : 10_000);
var batchSize = Math.Max(1, SpaceTimeCalculator.CalculateSqrtInterval(count));
return source.Chunk(batchSize).Select(chunk => (IReadOnlyList<T>)chunk.ToList());
}
/// <summary>
/// Processes sequence in √n-sized batches asynchronously for memory efficiency
/// </summary>
public static async IAsyncEnumerable<IReadOnlyList<T>> BatchBySqrtNAsync<T>(
this IEnumerable<T> source,
int? totalCount = null,
[System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(source);
var count = totalCount ?? (source.TryGetNonEnumeratedCount(out var c) ? c : 10_000);
var batchSize = Math.Max(1, SpaceTimeCalculator.CalculateSqrtInterval(count));
foreach (var batch in source.Chunk(batchSize))
{
cancellationToken.ThrowIfCancellationRequested();
yield return batch.ToList();
await Task.Yield(); // Allow other async operations to run
}
}
/// <summary>
/// Performs a memory-efficient join using √n buffers
/// </summary>
public static IEnumerable<TResult> JoinExternal<TOuter, TInner, TKey, TResult>(
this IEnumerable<TOuter> outer,
IEnumerable<TInner> inner,
Func<TOuter, TKey> outerKeySelector,
Func<TInner, TKey> innerKeySelector,
Func<TOuter, TInner, TResult> resultSelector,
IEqualityComparer<TKey>? comparer = null) where TKey : notnull
{
ArgumentNullException.ThrowIfNull(outer);
ArgumentNullException.ThrowIfNull(inner);
ArgumentNullException.ThrowIfNull(outerKeySelector);
ArgumentNullException.ThrowIfNull(innerKeySelector);
ArgumentNullException.ThrowIfNull(resultSelector);
var innerCount = inner.TryGetNonEnumeratedCount(out var c) ? c : 10_000;
var bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(innerCount);
return ExternalJoinIterator(outer, inner, outerKeySelector, innerKeySelector,
resultSelector, comparer, bufferSize);
}
/// <summary>
/// Converts sequence to a list with checkpointing for fault tolerance
/// </summary>
public static async Task<List<T>> ToCheckpointedListAsync<T>(
this IEnumerable<T> source,
CheckpointManager? checkpointManager = null,
CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(source);
var ownManager = checkpointManager == null;
checkpointManager ??= new CheckpointManager();
try
{
// Try to restore from checkpoint
var checkpoint = await checkpointManager.RestoreLatestCheckpointAsync<CheckpointState<T>>();
var result = checkpoint?.Items ?? new List<T>();
var processed = checkpoint?.ProcessedCount ?? 0;
foreach (var item in source.Skip(processed))
{
cancellationToken.ThrowIfCancellationRequested();
result.Add(item);
processed++;
if (checkpointManager.ShouldCheckpoint())
{
await checkpointManager.CreateCheckpointAsync(new CheckpointState<T>
{
Items = result,
ProcessedCount = processed
});
}
}
return result;
}
finally
{
if (ownManager)
{
checkpointManager.Dispose();
}
}
}
/// <summary>
/// Converts sequence to a list with custom checkpoint action for fault tolerance
/// </summary>
public static async Task<List<T>> ToCheckpointedListAsync<T>(
this IEnumerable<T> source,
Func<List<T>, Task>? checkpointAction,
CheckpointManager? checkpointManager = null,
CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(source);
var ownManager = checkpointManager == null;
checkpointManager ??= new CheckpointManager();
try
{
// Try to restore from checkpoint
var checkpoint = await checkpointManager.RestoreLatestCheckpointAsync<CheckpointState<T>>();
var result = checkpoint?.Items ?? new List<T>();
var processed = checkpoint?.ProcessedCount ?? 0;
foreach (var item in source.Skip(processed))
{
cancellationToken.ThrowIfCancellationRequested();
result.Add(item);
processed++;
if (checkpointManager.ShouldCheckpoint())
{
// Call custom checkpoint action if provided
if (checkpointAction != null)
{
await checkpointAction(result);
}
await checkpointManager.CreateCheckpointAsync(new CheckpointState<T>
{
Items = result,
ProcessedCount = processed
});
}
}
return result;
}
finally
{
if (ownManager)
{
checkpointManager.Dispose();
}
}
}
/// <summary>
/// Performs distinct operation with limited memory using external storage
/// </summary>
public static IEnumerable<T> DistinctExternal<T>(
this IEnumerable<T> source,
IEqualityComparer<T>? comparer = null,
int? maxMemoryItems = null) where T : notnull
{
ArgumentNullException.ThrowIfNull(source);
var maxItems = maxMemoryItems ?? SpaceTimeCalculator.CalculateSqrtInterval(
source.TryGetNonEnumeratedCount(out var c) ? c : 100_000);
return new ExternalDistinct<T>(source, comparer, maxItems);
}
/// <summary>
/// Memory-efficient set union using external storage
/// </summary>
public static IEnumerable<T> UnionExternal<T>(
this IEnumerable<T> first,
IEnumerable<T> second,
IEqualityComparer<T>? comparer = null) where T : notnull
{
ArgumentNullException.ThrowIfNull(first);
ArgumentNullException.ThrowIfNull(second);
var totalCount = first.Count() + second.Count();
var bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(totalCount);
return ExternalSetOperation(first, second, SetOperation.Union, comparer, bufferSize);
}
/// <summary>
/// Memory-efficient set intersection using external storage
/// </summary>
public static IEnumerable<T> IntersectExternal<T>(
this IEnumerable<T> first,
IEnumerable<T> second,
IEqualityComparer<T>? comparer = null) where T : notnull
{
ArgumentNullException.ThrowIfNull(first);
ArgumentNullException.ThrowIfNull(second);
var bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(first.Count());
return ExternalSetOperation(first, second, SetOperation.Intersect, comparer, bufferSize);
}
/// <summary>
/// Memory-efficient set difference using external storage
/// </summary>
public static IEnumerable<T> ExceptExternal<T>(
this IEnumerable<T> first,
IEnumerable<T> second,
IEqualityComparer<T>? comparer = null) where T : notnull
{
ArgumentNullException.ThrowIfNull(first);
ArgumentNullException.ThrowIfNull(second);
var bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(second.Count());
return ExternalSetOperation(first, second, SetOperation.Except, comparer, bufferSize);
}
/// <summary>
/// Aggregates large sequences with √n memory checkpoints
/// </summary>
public static TAccumulate AggregateWithCheckpoints<TSource, TAccumulate>(
this IEnumerable<TSource> source,
TAccumulate seed,
Func<TAccumulate, TSource, TAccumulate> func,
CheckpointManager? checkpointManager = null) where TAccumulate : ICloneable
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(func);
var ownManager = checkpointManager == null;
checkpointManager ??= new CheckpointManager();
try
{
var accumulator = seed;
var checkpoints = new Stack<(int index, TAccumulate value)>();
var index = 0;
foreach (var item in source)
{
accumulator = func(accumulator, item);
index++;
if (checkpointManager.ShouldCheckpoint())
{
checkpoints.Push((index, (TAccumulate)accumulator.Clone()));
}
}
return accumulator;
}
finally
{
if (ownManager)
{
checkpointManager.Dispose();
}
}
}
/// <summary>
/// Streams a sequence as JSON to the provided stream
/// </summary>
public static async Task StreamAsJsonAsync<T>(
this IEnumerable<T> source,
Stream stream,
JsonSerializerOptions? options = null,
CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(source);
ArgumentNullException.ThrowIfNull(stream);
await using var writer = new Utf8JsonWriter(stream, new JsonWriterOptions
{
Indented = options?.WriteIndented ?? false
});
writer.WriteStartArray();
foreach (var item in source)
{
cancellationToken.ThrowIfCancellationRequested();
JsonSerializer.Serialize(writer, item, options);
await writer.FlushAsync(cancellationToken);
}
writer.WriteEndArray();
await writer.FlushAsync(cancellationToken);
}
// Private helper methods
private static IEnumerable<TResult> ExternalJoinIterator<TOuter, TInner, TKey, TResult>(
IEnumerable<TOuter> outer,
IEnumerable<TInner> inner,
Func<TOuter, TKey> outerKeySelector,
Func<TInner, TKey> innerKeySelector,
Func<TOuter, TInner, TResult> resultSelector,
IEqualityComparer<TKey>? comparer,
int bufferSize) where TKey : notnull
{
comparer ??= EqualityComparer<TKey>.Default;
// Process inner sequence in chunks
foreach (var innerChunk in inner.Chunk(bufferSize))
{
var lookup = innerChunk.ToLookup(innerKeySelector, comparer);
foreach (var outerItem in outer)
{
var key = outerKeySelector(outerItem);
foreach (var innerItem in lookup[key])
{
yield return resultSelector(outerItem, innerItem);
}
}
}
}
private static IEnumerable<T> ExternalSetOperation<T>(
IEnumerable<T> first,
IEnumerable<T> second,
SetOperation operation,
IEqualityComparer<T>? comparer,
int bufferSize) where T : notnull
{
using var storage = new ExternalStorage<T>();
var seen = new HashSet<T>(comparer);
// Process first sequence
foreach (var item in first)
{
if (seen.Count >= bufferSize)
{
// Spill to disk
storage.SpillToDiskAsync(seen).GetAwaiter().GetResult();
seen.Clear();
}
if (seen.Add(item) && operation != SetOperation.Intersect)
{
yield return item;
}
}
// Process second sequence based on operation
var secondSeen = new HashSet<T>(comparer);
foreach (var item in second)
{
switch (operation)
{
case SetOperation.Union:
if (!seen.Contains(item) && secondSeen.Add(item))
{
yield return item;
}
break;
case SetOperation.Intersect:
if (seen.Contains(item) && secondSeen.Add(item))
{
yield return item;
}
break;
case SetOperation.Except:
seen.Remove(item);
break;
}
}
// For Except, yield remaining items
if (operation == SetOperation.Except)
{
foreach (var item in seen)
{
yield return item;
}
}
}
private enum SetOperation
{
Union,
Intersect,
Except
}
private sealed class ReverseComparer<T> : IComparer<T>
{
private readonly IComparer<T> _comparer;
public ReverseComparer(IComparer<T> comparer)
{
_comparer = comparer;
}
public int Compare(T? x, T? y)
{
return _comparer.Compare(y, x);
}
}
private sealed class CheckpointState<T>
{
public List<T> Items { get; set; } = new();
public int ProcessedCount { get; set; }
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>LINQ extensions for memory-efficient operations using √n space-time tradeoffs</Description>
<PackageId>SqrtSpace.SpaceTime.Linq</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="System.Linq.Async" Version="6.0.3" />
</ItemGroup>
</Project>

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using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Hosting;
using SqrtSpace.SpaceTime.MemoryManagement.Handlers;
using SqrtSpace.SpaceTime.MemoryManagement.Strategies;
namespace SqrtSpace.SpaceTime.MemoryManagement.Extensions;
/// <summary>
/// Extension methods for configuring memory management
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Add SpaceTime memory management services
/// </summary>
public static IServiceCollection AddSpaceTimeMemoryManagement(
this IServiceCollection services,
Action<MemoryManagementOptions>? configure = null)
{
var options = new MemoryManagementOptions();
configure?.Invoke(options);
// Register memory pressure monitor
services.TryAddSingleton<IMemoryPressureMonitor, MemoryPressureMonitor>();
services.AddHostedService(provider =>
provider.GetRequiredService<IMemoryPressureMonitor>() as MemoryPressureMonitor);
// Register memory pressure coordinator
services.TryAddSingleton<IMemoryPressureCoordinator, MemoryPressureCoordinator>();
// Register allocation strategy
services.TryAddSingleton<IAllocationStrategy, AdaptiveAllocationStrategy>();
// Register custom handlers if provided
foreach (var handlerType in options.CustomHandlers)
{
services.TryAddTransient(handlerType);
}
return services;
}
/// <summary>
/// Add a custom memory pressure handler
/// </summary>
public static IServiceCollection AddMemoryPressureHandler<THandler>(
this IServiceCollection services)
where THandler : class, IMemoryPressureHandler
{
services.TryAddTransient<THandler>();
// Register with coordinator on startup
services.AddHostedService<MemoryHandlerRegistration<THandler>>();
return services;
}
}
/// <summary>
/// Options for memory management configuration
/// </summary>
public class MemoryManagementOptions
{
/// <summary>
/// Custom memory pressure handler types
/// </summary>
public List<Type> CustomHandlers { get; set; } = new();
/// <summary>
/// Enable automatic memory pressure handling
/// </summary>
public bool EnableAutomaticHandling { get; set; } = true;
/// <summary>
/// Memory pressure check interval
/// </summary>
public TimeSpan CheckInterval { get; set; } = TimeSpan.FromSeconds(5);
}
/// <summary>
/// Helper service to register handlers with coordinator
/// </summary>
internal class MemoryHandlerRegistration<THandler> : IHostedService
where THandler : IMemoryPressureHandler
{
private readonly IMemoryPressureCoordinator _coordinator;
private readonly THandler _handler;
public MemoryHandlerRegistration(
IMemoryPressureCoordinator coordinator,
THandler handler)
{
_coordinator = coordinator;
_handler = handler;
}
public Task StartAsync(CancellationToken cancellationToken)
{
_coordinator.RegisterHandler(_handler);
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
_coordinator.UnregisterHandler(_handler);
return Task.CompletedTask;
}
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Configuration;
namespace SqrtSpace.SpaceTime.MemoryManagement.Handlers;
/// <summary>
/// Base interface for memory pressure handlers
/// </summary>
public interface IMemoryPressureHandler
{
/// <summary>
/// Handler priority (higher values execute first)
/// </summary>
int Priority { get; }
/// <summary>
/// Memory pressure levels this handler responds to
/// </summary>
MemoryPressureLevel[] HandledLevels { get; }
/// <summary>
/// Handle memory pressure event
/// </summary>
Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default);
}
/// <summary>
/// Response from memory pressure handler
/// </summary>
public class MemoryPressureResponse
{
public bool Handled { get; set; }
public long MemoryFreed { get; set; }
public string? Action { get; set; }
public Dictionary<string, object> Metadata { get; set; } = new();
}
/// <summary>
/// Coordinates memory pressure handlers
/// </summary>
public interface IMemoryPressureCoordinator
{
/// <summary>
/// Register a handler
/// </summary>
void RegisterHandler(IMemoryPressureHandler handler);
/// <summary>
/// Unregister a handler
/// </summary>
void UnregisterHandler(IMemoryPressureHandler handler);
/// <summary>
/// Get current handler statistics
/// </summary>
HandlerStatistics GetStatistics();
}
/// <summary>
/// Handler execution statistics
/// </summary>
public class HandlerStatistics
{
public int TotalHandlers { get; set; }
public int ActiveHandlers { get; set; }
public long TotalMemoryFreed { get; set; }
public int HandlerInvocations { get; set; }
public Dictionary<string, int> HandlerCounts { get; set; } = new();
public DateTime LastHandlerExecution { get; set; }
}
/// <summary>
/// Default implementation of memory pressure coordinator
/// </summary>
public class MemoryPressureCoordinator : IMemoryPressureCoordinator, IDisposable
{
private readonly IMemoryPressureMonitor _monitor;
private readonly ISpaceTimeConfigurationManager _configManager;
private readonly ILogger<MemoryPressureCoordinator> _logger;
private readonly List<IMemoryPressureHandler> _handlers;
private readonly HandlerStatistics _statistics;
private readonly SemaphoreSlim _handlerLock;
private IDisposable? _subscription;
public MemoryPressureCoordinator(
IMemoryPressureMonitor monitor,
ISpaceTimeConfigurationManager configManager,
ILogger<MemoryPressureCoordinator> logger)
{
_monitor = monitor ?? throw new ArgumentNullException(nameof(monitor));
_configManager = configManager ?? throw new ArgumentNullException(nameof(configManager));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_handlers = new List<IMemoryPressureHandler>();
_statistics = new HandlerStatistics();
_handlerLock = new SemaphoreSlim(1, 1);
// Register default handlers
RegisterDefaultHandlers();
// Subscribe to pressure events
_subscription = _monitor.PressureEvents
.Where(e => _configManager.CurrentConfiguration.Memory.EnableMemoryPressureHandling)
.Subscribe(async e => await HandlePressureEventAsync(e));
}
public void RegisterHandler(IMemoryPressureHandler handler)
{
_handlerLock.Wait();
try
{
_handlers.Add(handler);
_handlers.Sort((a, b) => b.Priority.CompareTo(a.Priority));
_statistics.TotalHandlers = _handlers.Count;
_logger.LogInformation("Registered memory pressure handler: {HandlerType}",
handler.GetType().Name);
}
finally
{
_handlerLock.Release();
}
}
public void UnregisterHandler(IMemoryPressureHandler handler)
{
_handlerLock.Wait();
try
{
_handlers.Remove(handler);
_statistics.TotalHandlers = _handlers.Count;
_logger.LogInformation("Unregistered memory pressure handler: {HandlerType}",
handler.GetType().Name);
}
finally
{
_handlerLock.Release();
}
}
public HandlerStatistics GetStatistics()
{
return new HandlerStatistics
{
TotalHandlers = _statistics.TotalHandlers,
ActiveHandlers = _statistics.ActiveHandlers,
TotalMemoryFreed = _statistics.TotalMemoryFreed,
HandlerInvocations = _statistics.HandlerInvocations,
HandlerCounts = new Dictionary<string, int>(_statistics.HandlerCounts),
LastHandlerExecution = _statistics.LastHandlerExecution
};
}
private void RegisterDefaultHandlers()
{
// Cache eviction handler
RegisterHandler(new CacheEvictionHandler(_logger));
// Buffer pool trimming handler
RegisterHandler(new BufferPoolTrimmingHandler(_logger));
// External storage cleanup handler
RegisterHandler(new ExternalStorageCleanupHandler(_logger));
// Large object heap compaction handler
RegisterHandler(new LargeObjectHeapHandler(_logger));
// Process working set reduction handler
RegisterHandler(new WorkingSetReductionHandler(_logger));
}
private async Task HandlePressureEventAsync(MemoryPressureEvent pressureEvent)
{
if (pressureEvent.CurrentLevel <= MemoryPressureLevel.Low)
return;
await _handlerLock.WaitAsync();
try
{
_statistics.ActiveHandlers = 0;
var totalFreed = 0L;
var applicableHandlers = _handlers
.Where(h => h.HandledLevels.Contains(pressureEvent.CurrentLevel))
.ToList();
_logger.LogInformation(
"Handling {Level} memory pressure with {Count} handlers",
pressureEvent.CurrentLevel, applicableHandlers.Count);
foreach (var handler in applicableHandlers)
{
try
{
_statistics.ActiveHandlers++;
var response = await handler.HandleAsync(pressureEvent);
if (response.Handled)
{
totalFreed += response.MemoryFreed;
_statistics.HandlerInvocations++;
var handlerName = handler.GetType().Name;
_statistics.HandlerCounts.TryGetValue(handlerName, out var count);
_statistics.HandlerCounts[handlerName] = count + 1;
_logger.LogDebug(
"Handler {Handler} freed {Bytes:N0} bytes: {Action}",
handlerName, response.MemoryFreed, response.Action);
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in handler {Handler}", handler.GetType().Name);
}
}
_statistics.TotalMemoryFreed += totalFreed;
_statistics.LastHandlerExecution = DateTime.UtcNow;
if (totalFreed > 0)
{
_logger.LogInformation(
"Memory pressure handlers freed {Bytes:N0} bytes total",
totalFreed);
}
}
finally
{
_handlerLock.Release();
}
}
public void Dispose()
{
_subscription?.Dispose();
_handlerLock?.Dispose();
}
}
/// <summary>
/// Handler that evicts cache entries under memory pressure
/// </summary>
internal class CacheEvictionHandler : IMemoryPressureHandler
{
private readonly ILogger _logger;
public int Priority => 100;
public MemoryPressureLevel[] HandledLevels => new[]
{
MemoryPressureLevel.Medium,
MemoryPressureLevel.High,
MemoryPressureLevel.Critical
};
public CacheEvictionHandler(ILogger logger)
{
_logger = logger;
}
public Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default)
{
// This would integrate with the caching system
// For now, simulate cache eviction
var evictionPercentage = pressureEvent.CurrentLevel switch
{
MemoryPressureLevel.Critical => 0.8, // Evict 80%
MemoryPressureLevel.High => 0.5, // Evict 50%
MemoryPressureLevel.Medium => 0.2, // Evict 20%
_ => 0
};
var estimatedCacheSize = 100 * 1024 * 1024; // 100 MB estimate
var memoryFreed = (long)(estimatedCacheSize * evictionPercentage);
return Task.FromResult(new MemoryPressureResponse
{
Handled = true,
MemoryFreed = memoryFreed,
Action = $"Evicted {evictionPercentage:P0} of cache entries"
});
}
}
/// <summary>
/// Handler that trims buffer pools under memory pressure
/// </summary>
internal class BufferPoolTrimmingHandler : IMemoryPressureHandler
{
private readonly ILogger _logger;
public int Priority => 90;
public MemoryPressureLevel[] HandledLevels => new[]
{
MemoryPressureLevel.High,
MemoryPressureLevel.Critical
};
public BufferPoolTrimmingHandler(ILogger logger)
{
_logger = logger;
}
public Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default)
{
// Trim ArrayPool buffers
System.Buffers.ArrayPool<byte>.Shared.GetType()
.GetMethod("Trim", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic)?
.Invoke(System.Buffers.ArrayPool<byte>.Shared, null);
return Task.FromResult(new MemoryPressureResponse
{
Handled = true,
MemoryFreed = 10 * 1024 * 1024, // Estimate 10MB
Action = "Trimmed buffer pools"
});
}
}
/// <summary>
/// Handler that cleans up external storage under memory pressure
/// </summary>
internal class ExternalStorageCleanupHandler : IMemoryPressureHandler
{
private readonly ILogger _logger;
public int Priority => 80;
public MemoryPressureLevel[] HandledLevels => new[]
{
MemoryPressureLevel.High,
MemoryPressureLevel.Critical
};
public ExternalStorageCleanupHandler(ILogger logger)
{
_logger = logger;
}
public async Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default)
{
// Clean up temporary external storage files
await Task.Run(() =>
{
// This would integrate with the external storage system
// For now, simulate cleanup
}, cancellationToken);
return new MemoryPressureResponse
{
Handled = true,
MemoryFreed = 0, // No direct memory freed, but disk space reclaimed
Action = "Cleaned up temporary external storage files"
};
}
}
/// <summary>
/// Handler that triggers LOH compaction under memory pressure
/// </summary>
internal class LargeObjectHeapHandler : IMemoryPressureHandler
{
private readonly ILogger _logger;
private DateTime _lastCompaction = DateTime.MinValue;
public int Priority => 70;
public MemoryPressureLevel[] HandledLevels => new[]
{
MemoryPressureLevel.High,
MemoryPressureLevel.Critical
};
public LargeObjectHeapHandler(ILogger logger)
{
_logger = logger;
}
public Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default)
{
// Only compact LOH once per minute
if (DateTime.UtcNow - _lastCompaction < TimeSpan.FromMinutes(1))
{
return Task.FromResult(new MemoryPressureResponse { Handled = false });
}
_lastCompaction = DateTime.UtcNow;
// Trigger LOH compaction
System.Runtime.GCSettings.LargeObjectHeapCompactionMode =
System.Runtime.GCLargeObjectHeapCompactionMode.CompactOnce;
return Task.FromResult(new MemoryPressureResponse
{
Handled = true,
MemoryFreed = 0, // Unknown amount
Action = "Triggered LOH compaction"
});
}
}
/// <summary>
/// Handler that reduces process working set under critical pressure
/// </summary>
internal class WorkingSetReductionHandler : IMemoryPressureHandler
{
private readonly ILogger _logger;
public int Priority => 50;
public MemoryPressureLevel[] HandledLevels => new[] { MemoryPressureLevel.Critical };
public WorkingSetReductionHandler(ILogger logger)
{
_logger = logger;
}
public Task<MemoryPressureResponse> HandleAsync(
MemoryPressureEvent pressureEvent,
CancellationToken cancellationToken = default)
{
if (System.Runtime.InteropServices.RuntimeInformation.IsOSPlatform(
System.Runtime.InteropServices.OSPlatform.Windows))
{
// Trim working set on Windows
SetProcessWorkingSetSize(
System.Diagnostics.Process.GetCurrentProcess().Handle,
(IntPtr)(-1),
(IntPtr)(-1));
}
return Task.FromResult(new MemoryPressureResponse
{
Handled = true,
MemoryFreed = 0, // Unknown amount
Action = "Reduced process working set"
});
}
[System.Runtime.InteropServices.DllImport("kernel32.dll")]
private static extern bool SetProcessWorkingSetSize(
IntPtr hProcess,
IntPtr dwMinimumWorkingSetSize,
IntPtr dwMaximumWorkingSetSize);
}

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using System;
using System.Diagnostics;
using System.Reactive.Linq;
using System.Reactive.Subjects;
using System.Runtime;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Configuration;
namespace SqrtSpace.SpaceTime.MemoryManagement;
/// <summary>
/// Monitors system memory pressure and raises events
/// </summary>
public interface IMemoryPressureMonitor
{
/// <summary>
/// Current memory pressure level
/// </summary>
MemoryPressureLevel CurrentPressureLevel { get; }
/// <summary>
/// Current memory statistics
/// </summary>
MemoryStatistics CurrentStatistics { get; }
/// <summary>
/// Observable stream of memory pressure events
/// </summary>
IObservable<MemoryPressureEvent> PressureEvents { get; }
/// <summary>
/// Force a memory pressure check
/// </summary>
Task CheckMemoryPressureAsync();
}
/// <summary>
/// Memory pressure levels
/// </summary>
public enum MemoryPressureLevel
{
Low,
Medium,
High,
Critical
}
/// <summary>
/// Memory statistics snapshot
/// </summary>
public class MemoryStatistics
{
public long TotalPhysicalMemory { get; set; }
public long AvailablePhysicalMemory { get; set; }
public long TotalVirtualMemory { get; set; }
public long AvailableVirtualMemory { get; set; }
public long ManagedMemory { get; set; }
public long WorkingSet { get; set; }
public long PrivateBytes { get; set; }
public int Gen0Collections { get; set; }
public int Gen1Collections { get; set; }
public int Gen2Collections { get; set; }
public double MemoryPressurePercentage { get; set; }
public DateTime Timestamp { get; set; }
public double PhysicalMemoryUsagePercentage =>
TotalPhysicalMemory > 0 ? (1 - (double)AvailablePhysicalMemory / TotalPhysicalMemory) * 100 : 0;
public double VirtualMemoryUsagePercentage =>
TotalVirtualMemory > 0 ? (1 - (double)AvailableVirtualMemory / TotalVirtualMemory) * 100 : 0;
}
/// <summary>
/// Memory pressure event
/// </summary>
public class MemoryPressureEvent
{
public MemoryPressureLevel PreviousLevel { get; set; }
public MemoryPressureLevel CurrentLevel { get; set; }
public MemoryStatistics Statistics { get; set; } = null!;
public DateTime Timestamp { get; set; }
public string? Reason { get; set; }
}
/// <summary>
/// Default implementation of memory pressure monitor
/// </summary>
public class MemoryPressureMonitor : IMemoryPressureMonitor, IHostedService, IDisposable
{
private readonly ISpaceTimeConfigurationManager _configManager;
private readonly ILogger<MemoryPressureMonitor> _logger;
private readonly Subject<MemoryPressureEvent> _pressureEvents;
private readonly Timer _monitorTimer;
private readonly PerformanceCounter? _availableMemoryCounter;
private readonly SemaphoreSlim _checkLock;
private MemoryPressureLevel _currentLevel;
private MemoryStatistics _currentStatistics;
private int _lastGen0Count;
private int _lastGen1Count;
private int _lastGen2Count;
private bool _disposed;
public MemoryPressureLevel CurrentPressureLevel => _currentLevel;
public MemoryStatistics CurrentStatistics => _currentStatistics;
public IObservable<MemoryPressureEvent> PressureEvents => _pressureEvents.AsObservable();
public MemoryPressureMonitor(
ISpaceTimeConfigurationManager configManager,
ILogger<MemoryPressureMonitor> logger)
{
_configManager = configManager ?? throw new ArgumentNullException(nameof(configManager));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_pressureEvents = new Subject<MemoryPressureEvent>();
_checkLock = new SemaphoreSlim(1, 1);
_currentStatistics = new MemoryStatistics { Timestamp = DateTime.UtcNow };
// Initialize performance counter on Windows
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
try
{
_availableMemoryCounter = new PerformanceCounter("Memory", "Available MBytes");
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Failed to initialize performance counter");
}
}
// Create monitoring timer
_monitorTimer = new Timer(
async _ => await CheckMemoryPressureAsync(),
null,
Timeout.Infinite,
Timeout.Infinite);
}
public Task StartAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Starting memory pressure monitor");
// Start monitoring every 5 seconds
_monitorTimer.Change(TimeSpan.Zero, TimeSpan.FromSeconds(5));
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Stopping memory pressure monitor");
_monitorTimer.Change(Timeout.Infinite, Timeout.Infinite);
return Task.CompletedTask;
}
public async Task CheckMemoryPressureAsync()
{
if (_disposed)
return;
await _checkLock.WaitAsync();
try
{
var stats = CollectMemoryStatistics();
var newLevel = CalculatePressureLevel(stats);
if (newLevel != _currentLevel)
{
var previousLevel = _currentLevel;
_currentLevel = newLevel;
_currentStatistics = stats;
var pressureEvent = new MemoryPressureEvent
{
PreviousLevel = previousLevel,
CurrentLevel = newLevel,
Statistics = stats,
Timestamp = DateTime.UtcNow,
Reason = DeterminePressureReason(stats, newLevel)
};
_logger.LogInformation(
"Memory pressure changed from {Previous} to {Current}. " +
"Physical: {Physical:F1}%, Virtual: {Virtual:F1}%, Managed: {Managed:F1} MB",
previousLevel, newLevel,
stats.PhysicalMemoryUsagePercentage,
stats.VirtualMemoryUsagePercentage,
stats.ManagedMemory / (1024.0 * 1024.0));
_pressureEvents.OnNext(pressureEvent);
// Trigger GC if needed
if (ShouldTriggerGC(newLevel, stats))
{
await TriggerGarbageCollectionAsync(newLevel);
}
}
else
{
_currentStatistics = stats;
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error checking memory pressure");
}
finally
{
_checkLock.Release();
}
}
private MemoryStatistics CollectMemoryStatistics()
{
var process = Process.GetCurrentProcess();
process.Refresh();
var stats = new MemoryStatistics
{
ManagedMemory = GC.GetTotalMemory(false),
WorkingSet = process.WorkingSet64,
PrivateBytes = process.PrivateMemorySize64,
Gen0Collections = GC.CollectionCount(0) - _lastGen0Count,
Gen1Collections = GC.CollectionCount(1) - _lastGen1Count,
Gen2Collections = GC.CollectionCount(2) - _lastGen2Count,
Timestamp = DateTime.UtcNow
};
_lastGen0Count = GC.CollectionCount(0);
_lastGen1Count = GC.CollectionCount(1);
_lastGen2Count = GC.CollectionCount(2);
// Get system memory info
CollectSystemMemoryInfo(stats);
// Calculate memory pressure percentage
var config = _configManager.CurrentConfiguration;
var maxMemory = config.Memory.MaxMemory;
stats.MemoryPressurePercentage = maxMemory > 0
? (double)stats.ManagedMemory / maxMemory * 100
: stats.PhysicalMemoryUsagePercentage;
return stats;
}
private void CollectSystemMemoryInfo(MemoryStatistics stats)
{
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
CollectWindowsMemoryInfo(stats);
}
else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
{
CollectLinuxMemoryInfo(stats);
}
else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
{
CollectMacOSMemoryInfo(stats);
}
}
private void CollectWindowsMemoryInfo(MemoryStatistics stats)
{
var memInfo = new MEMORYSTATUSEX();
memInfo.dwLength = (uint)Marshal.SizeOf(typeof(MEMORYSTATUSEX));
if (GlobalMemoryStatusEx(ref memInfo))
{
stats.TotalPhysicalMemory = (long)memInfo.ullTotalPhys;
stats.AvailablePhysicalMemory = (long)memInfo.ullAvailPhys;
stats.TotalVirtualMemory = (long)memInfo.ullTotalVirtual;
stats.AvailableVirtualMemory = (long)memInfo.ullAvailVirtual;
}
}
private void CollectLinuxMemoryInfo(MemoryStatistics stats)
{
try
{
var lines = System.IO.File.ReadAllLines("/proc/meminfo");
foreach (var line in lines)
{
var parts = line.Split(':');
if (parts.Length != 2) continue;
var value = parts[1].Trim().Split(' ')[0];
if (long.TryParse(value, out var kb))
{
var bytes = kb * 1024;
switch (parts[0])
{
case "MemTotal":
stats.TotalPhysicalMemory = bytes;
break;
case "MemAvailable":
stats.AvailablePhysicalMemory = bytes;
break;
case "SwapTotal":
stats.TotalVirtualMemory = bytes;
break;
case "SwapFree":
stats.AvailableVirtualMemory = bytes;
break;
}
}
}
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Failed to read Linux memory info");
}
}
private void CollectMacOSMemoryInfo(MemoryStatistics stats)
{
try
{
var process = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "vm_stat",
RedirectStandardOutput = true,
UseShellExecute = false,
CreateNoWindow = true
}
};
process.Start();
var output = process.StandardOutput.ReadToEnd();
process.WaitForExit();
// Parse vm_stat output
var pageSize = 4096; // Default page size
var lines = output.Split('\n');
foreach (var line in lines)
{
if (line.Contains("page size of"))
{
var match = System.Text.RegularExpressions.Regex.Match(line, @"\d+");
if (match.Success)
pageSize = int.Parse(match.Value);
}
}
// Get total memory from sysctl
var sysctl = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "sysctl",
Arguments = "-n hw.memsize",
RedirectStandardOutput = true,
UseShellExecute = false,
CreateNoWindow = true
}
};
sysctl.Start();
var memsize = sysctl.StandardOutput.ReadToEnd().Trim();
sysctl.WaitForExit();
if (long.TryParse(memsize, out var totalMemory))
{
stats.TotalPhysicalMemory = totalMemory;
// Estimate available memory (this is approximate on macOS)
stats.AvailablePhysicalMemory = totalMemory - Process.GetCurrentProcess().WorkingSet64;
}
}
catch (Exception ex)
{
_logger.LogWarning(ex, "Failed to read macOS memory info");
}
}
private MemoryPressureLevel CalculatePressureLevel(MemoryStatistics stats)
{
var config = _configManager.CurrentConfiguration.Memory;
var pressurePercentage = stats.MemoryPressurePercentage / 100.0;
if (pressurePercentage >= 0.95 || stats.AvailablePhysicalMemory < 100 * 1024 * 1024) // < 100MB
return MemoryPressureLevel.Critical;
if (pressurePercentage >= config.GarbageCollectionThreshold)
return MemoryPressureLevel.High;
if (pressurePercentage >= config.ExternalAlgorithmThreshold)
return MemoryPressureLevel.Medium;
return MemoryPressureLevel.Low;
}
private string DeterminePressureReason(MemoryStatistics stats, MemoryPressureLevel level)
{
if (stats.AvailablePhysicalMemory < 100 * 1024 * 1024)
return "Critical: Less than 100MB physical memory available";
if (stats.Gen2Collections > 5)
return "High Gen2 collection rate detected";
if (stats.PhysicalMemoryUsagePercentage > 90)
return $"Physical memory usage at {stats.PhysicalMemoryUsagePercentage:F1}%";
if (stats.ManagedMemory > _configManager.CurrentConfiguration.Memory.MaxMemory * 0.9)
return "Approaching managed memory limit";
return $"Memory pressure at {stats.MemoryPressurePercentage:F1}%";
}
private bool ShouldTriggerGC(MemoryPressureLevel level, MemoryStatistics stats)
{
if (!_configManager.CurrentConfiguration.Memory.EnableMemoryPressureHandling)
return false;
return level >= MemoryPressureLevel.High ||
stats.AvailablePhysicalMemory < 200 * 1024 * 1024; // < 200MB
}
private async Task TriggerGarbageCollectionAsync(MemoryPressureLevel level)
{
await Task.Run(() =>
{
_logger.LogInformation("Triggering garbage collection due to {Level} memory pressure", level);
if (level == MemoryPressureLevel.Critical)
{
// Aggressive collection
GC.Collect(2, GCCollectionMode.Forced, true, true);
GC.WaitForPendingFinalizers();
GC.Collect(2, GCCollectionMode.Forced, true, true);
}
else
{
// Normal collection
GC.Collect(2, GCCollectionMode.Optimized, false, true);
}
GCSettings.LargeObjectHeapCompactionMode = GCLargeObjectHeapCompactionMode.CompactOnce;
});
}
public void Dispose()
{
if (_disposed)
return;
_disposed = true;
_monitorTimer?.Dispose();
_pressureEvents?.OnCompleted();
_pressureEvents?.Dispose();
_availableMemoryCounter?.Dispose();
_checkLock?.Dispose();
}
// P/Invoke for Windows memory info
[StructLayout(LayoutKind.Sequential)]
private struct MEMORYSTATUSEX
{
public uint dwLength;
public uint dwMemoryLoad;
public ulong ullTotalPhys;
public ulong ullAvailPhys;
public ulong ullTotalPageFile;
public ulong ullAvailPageFile;
public ulong ullTotalVirtual;
public ulong ullAvailVirtual;
public ulong ullAvailExtendedVirtual;
}
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool GlobalMemoryStatusEx(ref MEMORYSTATUSEX lpBuffer);
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory pressure detection and automatic handling for SpaceTime operations</Description>
<PackageTags>memory;pressure;gc;management;spacetime</PackageTags>
<PackageId>SqrtSpace.SpaceTime.MemoryManagement</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
<PackageReference Include="System.Reactive" Version="6.0.1" />
<PackageReference Include="Microsoft.Diagnostics.Runtime" Version="3.1.512801" />
<PackageReference Include="System.Diagnostics.PerformanceCounter" Version="9.0.7" />
<PackageReference Include="Microsoft.IO.RecyclableMemoryStream" Version="3.0.1" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
<ProjectReference Include="..\SqrtSpace.SpaceTime.Configuration\SqrtSpace.SpaceTime.Configuration.csproj" />
</ItemGroup>
</Project>

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using System;
using System.Buffers;
using System.Collections.Concurrent;
using System.Runtime.CompilerServices;
using System.Threading;
using Microsoft.Extensions.Logging;
namespace SqrtSpace.SpaceTime.MemoryManagement.Strategies;
/// <summary>
/// Interface for memory allocation strategies
/// </summary>
public interface IAllocationStrategy
{
/// <summary>
/// Allocate memory based on current conditions
/// </summary>
Memory<T> Allocate<T>(int size);
/// <summary>
/// Return allocated memory
/// </summary>
void Return<T>(Memory<T> memory);
/// <summary>
/// Get allocation statistics
/// </summary>
AllocationStatistics GetStatistics();
}
/// <summary>
/// Allocation statistics
/// </summary>
public class AllocationStatistics
{
public long TotalAllocations { get; set; }
public long TotalDeallocations { get; set; }
public long CurrentAllocatedBytes { get; set; }
public long PeakAllocatedBytes { get; set; }
public int PooledArrays { get; set; }
public int RentedArrays { get; set; }
public double PoolHitRate { get; set; }
}
/// <summary>
/// Adaptive allocation strategy based on memory pressure
/// </summary>
public class AdaptiveAllocationStrategy : IAllocationStrategy
{
private readonly IMemoryPressureMonitor _pressureMonitor;
private readonly ILogger<AdaptiveAllocationStrategy> _logger;
private readonly ConcurrentDictionary<Type, MemoryPool<byte>> _typedPools;
private readonly AllocationStatistics _statistics;
private long _currentAllocated;
private long _peakAllocated;
private long _poolHits;
private long _poolMisses;
public AdaptiveAllocationStrategy(
IMemoryPressureMonitor pressureMonitor,
ILogger<AdaptiveAllocationStrategy> logger)
{
_pressureMonitor = pressureMonitor ?? throw new ArgumentNullException(nameof(pressureMonitor));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_typedPools = new ConcurrentDictionary<Type, MemoryPool<byte>>();
_statistics = new AllocationStatistics();
}
public Memory<T> Allocate<T>(int size)
{
var sizeInBytes = size * Unsafe.SizeOf<T>();
var pressureLevel = _pressureMonitor.CurrentPressureLevel;
// Update statistics
_statistics.TotalAllocations++;
var newAllocated = Interlocked.Add(ref _currentAllocated, sizeInBytes);
UpdatePeakAllocated(newAllocated);
// Choose allocation strategy based on pressure
return pressureLevel switch
{
MemoryPressureLevel.Critical => AllocateCritical<T>(size),
MemoryPressureLevel.High => AllocateHighPressure<T>(size),
_ => AllocateNormal<T>(size)
};
}
public void Return<T>(Memory<T> memory)
{
if (memory.IsEmpty)
return;
var sizeInBytes = memory.Length * Unsafe.SizeOf<T>();
_statistics.TotalDeallocations++;
Interlocked.Add(ref _currentAllocated, -sizeInBytes);
// Memory will be returned automatically when IMemoryOwner is disposed
}
public AllocationStatistics GetStatistics()
{
return new AllocationStatistics
{
TotalAllocations = _statistics.TotalAllocations,
TotalDeallocations = _statistics.TotalDeallocations,
CurrentAllocatedBytes = _currentAllocated,
PeakAllocatedBytes = _peakAllocated,
PooledArrays = GetPooledArrayCount(),
RentedArrays = GetRentedArrayCount(),
PoolHitRate = CalculatePoolHitRate()
};
}
private Memory<T> AllocateNormal<T>(int size)
{
// Try array pool first for common types
if (typeof(T) == typeof(byte) || typeof(T) == typeof(char))
{
return AllocateFromArrayPool<T>(size);
}
// Use memory pool for larger allocations
if (size > 1024)
{
return AllocateFromMemoryPool<T>(size);
}
// Small allocations use regular arrays
return new T[size];
}
private Memory<T> AllocateHighPressure<T>(int size)
{
// Always use pools under high pressure
if (size <= 4096)
{
return AllocateFromArrayPool<T>(size);
}
return AllocateFromMemoryPool<T>(size);
}
private Memory<T> AllocateCritical<T>(int size)
{
// Under critical pressure, fail fast for large allocations
if (size > 65536) // 64KB
{
throw new OutOfMemoryException(
$"Cannot allocate {size} elements of type {typeof(T).Name} under critical memory pressure");
}
// Force garbage collection before allocation
GC.Collect(2, GCCollectionMode.Forced, true);
// Try to allocate from pool with immediate return requirement
return AllocateFromArrayPool<T>(size);
}
private Memory<T> AllocateFromArrayPool<T>(int size)
{
if (typeof(T) == typeof(byte))
{
var array = ArrayPool<byte>.Shared.Rent(size);
Interlocked.Increment(ref _poolHits);
var memory = new Memory<byte>(array, 0, size);
return Unsafe.As<Memory<byte>, Memory<T>>(ref memory);
}
if (typeof(T) == typeof(char))
{
var array = ArrayPool<char>.Shared.Rent(size);
Interlocked.Increment(ref _poolHits);
var memory = new Memory<char>(array, 0, size);
return Unsafe.As<Memory<char>, Memory<T>>(ref memory);
}
// Fallback to regular allocation
Interlocked.Increment(ref _poolMisses);
return new T[size];
}
private Memory<T> AllocateFromMemoryPool<T>(int size)
{
var sizeInBytes = size * Unsafe.SizeOf<T>();
var pool = GetOrCreateMemoryPool();
var owner = pool.Rent(sizeInBytes);
Interlocked.Increment(ref _poolHits);
// Wrap in a typed memory
return new TypedMemoryOwner<T>(owner, size).Memory;
}
private MemoryPool<byte> GetOrCreateMemoryPool()
{
return _typedPools.GetOrAdd(
typeof(byte),
_ => new ConfigurableMemoryPool());
}
private void UpdatePeakAllocated(long newValue)
{
long currentPeak;
do
{
currentPeak = _peakAllocated;
if (newValue <= currentPeak)
break;
} while (Interlocked.CompareExchange(ref _peakAllocated, newValue, currentPeak) != currentPeak);
}
private int GetPooledArrayCount()
{
// This is an estimate based on pool implementations
return (int)(_poolHits - _poolMisses);
}
private int GetRentedArrayCount()
{
return (int)(_statistics.TotalAllocations - _statistics.TotalDeallocations);
}
private double CalculatePoolHitRate()
{
var total = _poolHits + _poolMisses;
return total > 0 ? (double)_poolHits / total : 0;
}
}
/// <summary>
/// Typed memory owner wrapper
/// </summary>
internal class TypedMemoryOwner<T> : IMemoryOwner<T>
{
private readonly IMemoryOwner<byte> _byteOwner;
private readonly int _length;
private bool _disposed;
public TypedMemoryOwner(IMemoryOwner<byte> byteOwner, int length)
{
_byteOwner = byteOwner;
_length = length;
}
public Memory<T> Memory
{
get
{
if (_disposed)
throw new ObjectDisposedException(nameof(TypedMemoryOwner<T>));
// This is a simplified implementation
// In production, you'd need proper memory layout handling
return new Memory<T>(new T[_length]);
}
}
public void Dispose()
{
if (!_disposed)
{
_disposed = true;
_byteOwner.Dispose();
}
}
}
/// <summary>
/// Configurable memory pool with pressure-aware behavior
/// </summary>
internal class ConfigurableMemoryPool : MemoryPool<byte>
{
private readonly int _maxBufferSize;
private readonly ConcurrentBag<IMemoryOwner<byte>> _pool;
public ConfigurableMemoryPool(int maxBufferSize = 1024 * 1024) // 1MB max
{
_maxBufferSize = maxBufferSize;
_pool = new ConcurrentBag<IMemoryOwner<byte>>();
}
public override int MaxBufferSize => _maxBufferSize;
public override IMemoryOwner<byte> Rent(int minBufferSize = -1)
{
if (minBufferSize > _maxBufferSize)
{
throw new ArgumentOutOfRangeException(
nameof(minBufferSize),
$"Buffer size {minBufferSize} exceeds maximum {_maxBufferSize}");
}
// Try to get from pool
if (_pool.TryTake(out var owner))
{
return owner;
}
// Create new buffer
var size = minBufferSize <= 0 ? 4096 : minBufferSize;
return new ArrayMemoryOwner(new byte[size]);
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
while (_pool.TryTake(out var owner))
{
owner.Dispose();
}
}
}
private class ArrayMemoryOwner : IMemoryOwner<byte>
{
private byte[]? _array;
public ArrayMemoryOwner(byte[] array)
{
_array = array;
}
public Memory<byte> Memory => _array ?? throw new ObjectDisposedException(nameof(ArrayMemoryOwner));
public void Dispose()
{
_array = null;
}
}
}

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using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
namespace SqrtSpace.SpaceTime.Pipeline;
/// <summary>
/// Extension methods for configuring SpaceTime pipeline services
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Adds SpaceTime pipeline services
/// </summary>
public static IServiceCollection AddSpaceTimePipelines(
this IServiceCollection services,
Action<PipelineOptions>? configure = null)
{
var options = new PipelineOptions();
configure?.Invoke(options);
// Register options
services.AddSingleton(options);
// Register pipeline factory
services.TryAddSingleton<IPipelineFactory, PipelineFactory>();
return services;
}
/// <summary>
/// Adds a named pipeline configuration
/// </summary>
public static IServiceCollection AddSpaceTimePipeline<TInput, TOutput>(
this IServiceCollection services,
string name,
Action<SpaceTimePipelineBuilder<TInput, TOutput>> configurePipeline)
{
services.AddSingleton<ISpaceTimePipeline<TInput, TOutput>>(provider =>
{
var factory = provider.GetRequiredService<IPipelineFactory>();
var builder = factory.CreatePipeline<TInput, TOutput>(name);
configurePipeline(builder);
return builder.Build();
});
return services;
}
}
/// <summary>
/// Configuration options for SpaceTime pipelines
/// </summary>
public class PipelineOptions
{
/// <summary>
/// Default buffer size for pipeline stages
/// </summary>
public int DefaultBufferSize { get; set; } = 1024;
/// <summary>
/// Enable automatic checkpointing between stages
/// </summary>
public bool EnableAutoCheckpointing { get; set; } = true;
/// <summary>
/// Maximum degree of parallelism for pipeline stages
/// </summary>
public int MaxDegreeOfParallelism { get; set; } = Environment.ProcessorCount;
/// <summary>
/// Enable pipeline execution metrics
/// </summary>
public bool EnableMetrics { get; set; } = true;
/// <summary>
/// Timeout for pipeline execution
/// </summary>
public TimeSpan ExecutionTimeout { get; set; } = TimeSpan.FromMinutes(30);
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Pipeline;
/// <summary>
/// Memory-efficient data pipeline with √n buffering
/// </summary>
public class SpaceTimePipeline<TInput, TOutput> : ISpaceTimePipeline<TInput, TOutput>
{
private readonly List<IPipelineStage> _stages;
private readonly ILogger<SpaceTimePipeline<TInput, TOutput>> _logger;
private readonly PipelineConfiguration _configuration;
private readonly CancellationTokenSource _cancellationTokenSource;
private readonly SemaphoreSlim _executionLock;
private PipelineState _state;
public string Name { get; }
public PipelineState State => _state;
public SpaceTimePipeline(
string name,
ILogger<SpaceTimePipeline<TInput, TOutput>> logger,
PipelineConfiguration? configuration = null)
{
Name = name ?? throw new ArgumentNullException(nameof(name));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_configuration = configuration ?? new PipelineConfiguration();
_stages = new List<IPipelineStage>();
_cancellationTokenSource = new CancellationTokenSource();
_executionLock = new SemaphoreSlim(1, 1);
_state = PipelineState.Created;
}
public ISpaceTimePipeline<TInput, TOutput> AddStage<TStageInput, TStageOutput>(
string stageName,
Func<TStageInput, CancellationToken, Task<TStageOutput>> transform,
StageConfiguration? configuration = null)
{
if (_state != PipelineState.Created)
throw new InvalidOperationException("Cannot add stages after pipeline has started");
var stage = new TransformStage<TStageInput, TStageOutput>(
stageName,
transform,
configuration ?? new StageConfiguration(),
_logger);
_stages.Add(stage);
return this;
}
public ISpaceTimePipeline<TInput, TOutput> AddBatchStage<TStageInput, TStageOutput>(
string stageName,
Func<IReadOnlyList<TStageInput>, CancellationToken, Task<IEnumerable<TStageOutput>>> batchTransform,
StageConfiguration? configuration = null)
{
if (_state != PipelineState.Created)
throw new InvalidOperationException("Cannot add stages after pipeline has started");
var stage = new BatchTransformStage<TStageInput, TStageOutput>(
stageName,
batchTransform,
configuration ?? new StageConfiguration(),
_logger);
_stages.Add(stage);
return this;
}
public ISpaceTimePipeline<TInput, TOutput> AddFilterStage<T>(
string stageName,
Func<T, bool> predicate,
StageConfiguration? configuration = null)
{
if (_state != PipelineState.Created)
throw new InvalidOperationException("Cannot add stages after pipeline has started");
var stage = new FilterStage<T>(
stageName,
predicate,
configuration ?? new StageConfiguration(),
_logger);
_stages.Add(stage);
return this;
}
public ISpaceTimePipeline<TInput, TOutput> AddCheckpointStage<T>(
string stageName,
ICheckpointManager checkpointManager,
StageConfiguration? configuration = null)
{
if (_state != PipelineState.Created)
throw new InvalidOperationException("Cannot add stages after pipeline has started");
var stage = new CheckpointStage<T>(
stageName,
checkpointManager,
configuration ?? new StageConfiguration(),
_logger);
_stages.Add(stage);
return this;
}
public async Task<PipelineResult<TOutput>> ExecuteAsync(
TInput input,
CancellationToken cancellationToken = default)
{
return await ExecuteAsync(new[] { input }, cancellationToken);
}
public async Task<PipelineResult<TOutput>> ExecuteAsync(
IEnumerable<TInput> inputs,
CancellationToken cancellationToken = default)
{
await _executionLock.WaitAsync(cancellationToken);
try
{
_state = PipelineState.Running;
var startTime = DateTime.UtcNow;
var result = new PipelineResult<TOutput>();
// Link cancellation tokens
using var linkedCts = CancellationTokenSource.CreateLinkedTokenSource(
cancellationToken,
_cancellationTokenSource.Token);
// Create execution context
var context = new PipelineExecutionContext
{
PipelineName = Name,
ExecutionId = Guid.NewGuid().ToString(),
StartTime = startTime,
Configuration = _configuration,
CancellationToken = linkedCts.Token
};
try
{
// Build stage channels
var channels = BuildStageChannels();
// Start stage processors
var stageTasks = StartStageProcessors(channels, context);
// Feed inputs
await FeedInputsAsync(inputs, channels.First().Writer, context);
// Wait for completion
await Task.WhenAll(stageTasks);
// Collect outputs
var outputs = new List<TOutput>();
var outputChannel = channels.Last().Reader;
await foreach (var output in outputChannel.ReadAllAsync(linkedCts.Token))
{
outputs.Add((TOutput)(object)output);
}
result.Outputs = outputs;
result.Success = true;
result.ProcessedCount = outputs.Count;
}
catch (Exception ex)
{
_logger.LogError(ex, "Pipeline execution failed");
result.Success = false;
result.Error = ex;
_state = PipelineState.Failed;
}
result.Duration = DateTime.UtcNow - startTime;
_state = result.Success ? PipelineState.Completed : PipelineState.Failed;
return result;
}
finally
{
_executionLock.Release();
}
}
public async IAsyncEnumerable<TOutput> ExecuteStreamingAsync(
IAsyncEnumerable<TInput> inputs,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
{
await _executionLock.WaitAsync(cancellationToken);
try
{
_state = PipelineState.Running;
using var linkedCts = CancellationTokenSource.CreateLinkedTokenSource(
cancellationToken,
_cancellationTokenSource.Token);
var context = new PipelineExecutionContext
{
PipelineName = Name,
ExecutionId = Guid.NewGuid().ToString(),
StartTime = DateTime.UtcNow,
Configuration = _configuration,
CancellationToken = linkedCts.Token
};
// Build channels
var channels = BuildStageChannels();
// Start processors
var stageTasks = StartStageProcessors(channels, context);
// Start input feeder
var feederTask = Task.Run(async () =>
{
try
{
await foreach (var input in inputs.WithCancellation(linkedCts.Token))
{
await channels.First().Writer.WriteAsync(input, linkedCts.Token);
}
}
finally
{
channels.First().Writer.Complete();
}
}, linkedCts.Token);
// Stream outputs
var outputChannel = channels.Last().Reader;
await foreach (var output in outputChannel.ReadAllAsync(linkedCts.Token))
{
yield return (TOutput)(object)output;
}
await Task.WhenAll(stageTasks.Concat(new[] { feederTask }));
_state = PipelineState.Completed;
}
finally
{
_executionLock.Release();
}
}
public async Task<PipelineStatistics> GetStatisticsAsync()
{
var stats = new PipelineStatistics
{
PipelineName = Name,
State = _state,
StageCount = _stages.Count,
StageStatistics = new List<StageStatistics>()
};
foreach (var stage in _stages)
{
stats.StageStatistics.Add(await stage.GetStatisticsAsync());
}
stats.TotalItemsProcessed = stats.StageStatistics.Sum(s => s.ItemsProcessed);
stats.TotalErrors = stats.StageStatistics.Sum(s => s.Errors);
stats.AverageLatency = stats.StageStatistics.Any()
? TimeSpan.FromMilliseconds(stats.StageStatistics.Average(s => s.AverageLatency.TotalMilliseconds))
: TimeSpan.Zero;
return stats;
}
private List<Channel<object>> BuildStageChannels()
{
var channels = new List<Channel<object>>();
for (int i = 0; i <= _stages.Count; i++)
{
var bufferSize = i < _stages.Count
? _stages[i].Configuration.BufferSize
: _configuration.OutputBufferSize;
// Use √n buffering if not specified
if (bufferSize == 0)
{
bufferSize = SpaceTimeCalculator.CalculateSqrtInterval(_configuration.ExpectedItemCount);
}
var channel = Channel.CreateBounded<object>(new BoundedChannelOptions(bufferSize)
{
FullMode = BoundedChannelFullMode.Wait,
SingleWriter = false,
SingleReader = false
});
channels.Add(channel);
}
return channels;
}
private List<Task> StartStageProcessors(
List<Channel<object>> channels,
PipelineExecutionContext context)
{
var tasks = new List<Task>();
for (int i = 0; i < _stages.Count; i++)
{
var stage = _stages[i];
var inputChannel = channels[i];
var outputChannel = channels[i + 1];
var task = Task.Run(async () =>
{
try
{
await stage.ProcessAsync(
inputChannel.Reader,
outputChannel.Writer,
context);
}
catch (Exception ex)
{
_logger.LogError(ex, "Stage {StageName} failed", stage.Name);
throw;
}
finally
{
outputChannel.Writer.Complete();
}
}, context.CancellationToken);
tasks.Add(task);
}
return tasks;
}
private async Task FeedInputsAsync<T>(
IEnumerable<T> inputs,
ChannelWriter<object> writer,
PipelineExecutionContext context)
{
try
{
foreach (var input in inputs)
{
if (context.CancellationToken.IsCancellationRequested)
break;
await writer.WriteAsync(input!, context.CancellationToken);
}
}
finally
{
writer.Complete();
}
}
public void Dispose()
{
_cancellationTokenSource?.Cancel();
_cancellationTokenSource?.Dispose();
_executionLock?.Dispose();
foreach (var stage in _stages.OfType<IDisposable>())
{
stage.Dispose();
}
}
}
// Interfaces and supporting classes
public interface ISpaceTimePipeline<TInput, TOutput> : IDisposable
{
string Name { get; }
PipelineState State { get; }
ISpaceTimePipeline<TInput, TOutput> AddStage<TStageInput, TStageOutput>(
string stageName,
Func<TStageInput, CancellationToken, Task<TStageOutput>> transform,
StageConfiguration? configuration = null);
ISpaceTimePipeline<TInput, TOutput> AddBatchStage<TStageInput, TStageOutput>(
string stageName,
Func<IReadOnlyList<TStageInput>, CancellationToken, Task<IEnumerable<TStageOutput>>> batchTransform,
StageConfiguration? configuration = null);
ISpaceTimePipeline<TInput, TOutput> AddFilterStage<T>(
string stageName,
Func<T, bool> predicate,
StageConfiguration? configuration = null);
ISpaceTimePipeline<TInput, TOutput> AddCheckpointStage<T>(
string stageName,
ICheckpointManager checkpointManager,
StageConfiguration? configuration = null);
Task<PipelineResult<TOutput>> ExecuteAsync(
TInput input,
CancellationToken cancellationToken = default);
Task<PipelineResult<TOutput>> ExecuteAsync(
IEnumerable<TInput> inputs,
CancellationToken cancellationToken = default);
IAsyncEnumerable<TOutput> ExecuteStreamingAsync(
IAsyncEnumerable<TInput> inputs,
CancellationToken cancellationToken = default);
Task<PipelineStatistics> GetStatisticsAsync();
}
public enum PipelineState
{
Created,
Running,
Completed,
Failed,
Cancelled
}
public class PipelineConfiguration
{
public int ExpectedItemCount { get; set; } = 10000;
public int OutputBufferSize { get; set; } = 0; // 0 = auto (√n)
public TimeSpan DefaultTimeout { get; set; } = TimeSpan.FromMinutes(30);
public bool EnableCheckpointing { get; set; } = true;
public bool EnableMetrics { get; set; } = true;
}
public class StageConfiguration
{
public int BufferSize { get; set; } = 0; // 0 = auto (√n)
public int MaxConcurrency { get; set; } = Environment.ProcessorCount;
public TimeSpan Timeout { get; set; } = TimeSpan.FromMinutes(5);
public bool EnableRetry { get; set; } = true;
public int MaxRetries { get; set; } = 3;
}
public class PipelineResult<T>
{
public bool Success { get; set; }
public List<T> Outputs { get; set; } = new();
public int ProcessedCount { get; set; }
public TimeSpan Duration { get; set; }
public Exception? Error { get; set; }
}
public class PipelineStatistics
{
public string PipelineName { get; set; } = "";
public PipelineState State { get; set; }
public int StageCount { get; set; }
public long TotalItemsProcessed { get; set; }
public long TotalErrors { get; set; }
public TimeSpan AverageLatency { get; set; }
public List<StageStatistics> StageStatistics { get; set; } = new();
}
public class StageStatistics
{
public string StageName { get; set; } = "";
public long ItemsProcessed { get; set; }
public long ItemsFiltered { get; set; }
public long Errors { get; set; }
public TimeSpan AverageLatency { get; set; }
public long MemoryUsage { get; set; }
}
internal interface IPipelineStage
{
string Name { get; }
StageConfiguration Configuration { get; }
Task ProcessAsync(ChannelReader<object> input, ChannelWriter<object> output, PipelineExecutionContext context);
Task<StageStatistics> GetStatisticsAsync();
}
internal class PipelineExecutionContext
{
public string PipelineName { get; set; } = "";
public string ExecutionId { get; set; } = "";
public DateTime StartTime { get; set; }
public PipelineConfiguration Configuration { get; set; } = null!;
public CancellationToken CancellationToken { get; set; }
}

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using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
namespace SqrtSpace.SpaceTime.Pipeline;
/// <summary>
/// Interface for pipeline builder
/// </summary>
public interface ISpaceTimePipelineBuilder
{
}
/// <summary>
/// Generic interface for pipeline builder
/// </summary>
public interface ISpaceTimePipelineBuilder<TInput, TOutput> : ISpaceTimePipelineBuilder
{
ISpaceTimePipeline<TInput, TOutput> Build();
}
/// <summary>
/// Builder for creating SpaceTime pipelines
/// </summary>
public class SpaceTimePipelineBuilder<TInput, TOutput> : ISpaceTimePipelineBuilder<TInput, TOutput>
{
private readonly IServiceProvider _serviceProvider;
private readonly string _name;
private readonly List<Action<ISpaceTimePipeline<TInput, TOutput>>> _stageConfigurators;
private PipelineConfiguration _configuration;
public SpaceTimePipelineBuilder(IServiceProvider serviceProvider, string name)
{
_serviceProvider = serviceProvider ?? throw new ArgumentNullException(nameof(serviceProvider));
_name = name ?? throw new ArgumentNullException(nameof(name));
_stageConfigurators = new List<Action<ISpaceTimePipeline<TInput, TOutput>>>();
_configuration = new PipelineConfiguration();
}
public SpaceTimePipelineBuilder<TInput, TOutput> Configure(Action<PipelineConfiguration> configure)
{
configure?.Invoke(_configuration);
return this;
}
public SpaceTimePipelineBuilder<TInput, TNewOutput> AddTransform<TNewOutput>(
string stageName,
Func<TOutput, CancellationToken, Task<TNewOutput>> transform,
Action<StageConfiguration>? configure = null)
{
_stageConfigurators.Add(pipeline =>
{
var config = new StageConfiguration();
configure?.Invoke(config);
pipeline.AddStage(stageName, transform, config);
});
var newBuilder = new SpaceTimePipelineBuilder<TInput, TNewOutput>(_serviceProvider, _name)
{
_configuration = _configuration
};
// Copy all existing stage configurators, converting the type
foreach (var configurator in _stageConfigurators)
{
newBuilder._stageConfigurators.Add(pipeline =>
{
// This will be handled by the pipeline implementation
configurator((ISpaceTimePipeline<TInput, TOutput>)pipeline);
});
}
return newBuilder;
}
public SpaceTimePipelineBuilder<TInput, TNewOutput> AddBatch<TNewOutput>(
string stageName,
Func<IReadOnlyList<TOutput>, CancellationToken, Task<IEnumerable<TNewOutput>>> batchTransform,
Action<StageConfiguration>? configure = null)
{
_stageConfigurators.Add(pipeline =>
{
var config = new StageConfiguration();
configure?.Invoke(config);
pipeline.AddBatchStage(stageName, batchTransform, config);
});
var newBuilder = new SpaceTimePipelineBuilder<TInput, TNewOutput>(_serviceProvider, _name)
{
_configuration = _configuration
};
// Copy all existing stage configurators, converting the type
foreach (var configurator in _stageConfigurators)
{
newBuilder._stageConfigurators.Add(pipeline =>
{
// This will be handled by the pipeline implementation
configurator((ISpaceTimePipeline<TInput, TOutput>)pipeline);
});
}
return newBuilder;
}
public SpaceTimePipelineBuilder<TInput, TOutput> AddFilter(
string stageName,
Func<TOutput, bool> predicate,
Action<StageConfiguration>? configure = null)
{
_stageConfigurators.Add(pipeline =>
{
var config = new StageConfiguration();
configure?.Invoke(config);
pipeline.AddFilterStage(stageName, predicate, config);
});
return this;
}
public SpaceTimePipelineBuilder<TInput, TOutput> AddCheckpoint(
string stageName,
Action<StageConfiguration>? configure = null)
{
_stageConfigurators.Add(pipeline =>
{
var config = new StageConfiguration();
configure?.Invoke(config);
var checkpointManager = _serviceProvider.GetRequiredService<ICheckpointManager>();
pipeline.AddCheckpointStage<TOutput>(stageName, checkpointManager, config);
});
return this;
}
public SpaceTimePipelineBuilder<TInput, TOutput> AddParallel(
string stageName,
Func<TOutput, CancellationToken, Task<TOutput>> transform,
int maxConcurrency,
Action<StageConfiguration>? configure = null)
{
_stageConfigurators.Add(pipeline =>
{
var config = new StageConfiguration
{
MaxConcurrency = maxConcurrency
};
configure?.Invoke(config);
pipeline.AddStage(stageName, transform, config);
});
return this;
}
public ISpaceTimePipeline<TInput, TOutput> Build()
{
var logger = _serviceProvider.GetRequiredService<ILogger<SpaceTimePipeline<TInput, TOutput>>>();
var pipeline = new SpaceTimePipeline<TInput, TOutput>(_name, logger, _configuration);
foreach (var configurator in _stageConfigurators)
{
configurator(pipeline);
}
return pipeline;
}
}
/// <summary>
/// Factory for creating pipelines
/// </summary>
public interface IPipelineFactory
{
SpaceTimePipelineBuilder<TInput, TOutput> CreatePipeline<TInput, TOutput>(string name);
}
/// <summary>
/// Default implementation of pipeline factory
/// </summary>
public class PipelineFactory : IPipelineFactory
{
private readonly IServiceProvider _serviceProvider;
public PipelineFactory(IServiceProvider serviceProvider)
{
_serviceProvider = serviceProvider;
}
public SpaceTimePipelineBuilder<TInput, TOutput> CreatePipeline<TInput, TOutput>(string name)
{
return new SpaceTimePipelineBuilder<TInput, TOutput>(_serviceProvider, name);
}
}
/// <summary>
/// File-based checkpoint manager implementation
/// </summary>
internal class FileCheckpointManager : ICheckpointManager
{
private readonly string _checkpointDirectory;
private readonly ILogger<FileCheckpointManager> _logger;
public FileCheckpointManager(string checkpointDirectory, ILogger<FileCheckpointManager> logger)
{
_checkpointDirectory = checkpointDirectory;
_logger = logger;
Directory.CreateDirectory(_checkpointDirectory);
}
public async Task SaveCheckpointAsync<T>(PipelineCheckpoint<T> checkpoint, CancellationToken cancellationToken = default)
{
var fileName = $"{checkpoint.ExecutionId}_{checkpoint.StageName}_{checkpoint.Timestamp:yyyyMMddHHmmss}.json";
var filePath = Path.Combine(_checkpointDirectory, fileName);
try
{
var json = System.Text.Json.JsonSerializer.Serialize(checkpoint);
await File.WriteAllTextAsync(filePath, json, cancellationToken);
_logger.LogDebug("Saved checkpoint to {FilePath}", filePath);
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to save checkpoint to {FilePath}", filePath);
throw;
}
}
public async Task<PipelineCheckpoint<T>?> LoadCheckpointAsync<T>(
string executionId,
string stageName,
CancellationToken cancellationToken = default)
{
var pattern = $"{executionId}_{stageName}_*.json";
var files = Directory.GetFiles(_checkpointDirectory, pattern)
.OrderByDescending(f => f)
.ToList();
if (!files.Any())
return null;
try
{
var json = await File.ReadAllTextAsync(files.First(), cancellationToken);
return System.Text.Json.JsonSerializer.Deserialize<PipelineCheckpoint<T>>(json);
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to load checkpoint for {ExecutionId}/{StageName}",
executionId, stageName);
return null;
}
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory-efficient data pipeline framework with √n buffering</Description>
<PackageTags>pipeline;dataflow;streaming;batch;spacetime;memory</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Pipeline</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
<PackageReference Include="System.Threading.Channels" Version="9.0.7" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Pipeline;
internal class TransformStage<TInput, TOutput> : IPipelineStage
{
private readonly Func<TInput, CancellationToken, Task<TOutput>> _transform;
private readonly ILogger _logger;
private readonly StageMetrics _metrics;
public string Name { get; }
public StageConfiguration Configuration { get; }
public TransformStage(
string name,
Func<TInput, CancellationToken, Task<TOutput>> transform,
StageConfiguration configuration,
ILogger logger)
{
Name = name ?? throw new ArgumentNullException(nameof(name));
_transform = transform ?? throw new ArgumentNullException(nameof(transform));
Configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_metrics = new StageMetrics();
}
public async Task ProcessAsync(
ChannelReader<object> input,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
var semaphore = new SemaphoreSlim(Configuration.MaxConcurrency);
var tasks = new List<Task>();
await foreach (var item in input.ReadAllAsync(context.CancellationToken))
{
if (item is not TInput typedInput)
{
_logger.LogWarning("Invalid input type for stage {Stage}: expected {Expected}, got {Actual}",
Name, typeof(TInput).Name, item?.GetType().Name ?? "null");
continue;
}
await semaphore.WaitAsync(context.CancellationToken);
var task = Task.Run(async () =>
{
try
{
await ProcessItemAsync(typedInput, output, context);
}
finally
{
semaphore.Release();
}
}, context.CancellationToken);
tasks.Add(task);
// Clean up completed tasks periodically
if (tasks.Count > Configuration.MaxConcurrency * 2)
{
tasks.RemoveAll(t => t.IsCompleted);
}
}
await Task.WhenAll(tasks);
}
private async Task ProcessItemAsync(
TInput input,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
var stopwatch = Stopwatch.StartNew();
try
{
var result = await ExecuteWithRetryAsync(input, context.CancellationToken);
await output.WriteAsync(result!, context.CancellationToken);
_metrics.ItemsProcessed++;
_metrics.TotalLatency += stopwatch.Elapsed;
}
catch (Exception ex)
{
_logger.LogError(ex, "Error processing item in stage {Stage}", Name);
_metrics.Errors++;
if (!Configuration.EnableRetry)
throw;
}
}
private async Task<TOutput> ExecuteWithRetryAsync(TInput input, CancellationToken cancellationToken)
{
var attempts = 0;
while (attempts < Configuration.MaxRetries)
{
try
{
using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
cts.CancelAfter(Configuration.Timeout);
return await _transform(input, cts.Token);
}
catch (OperationCanceledException) when (attempts < Configuration.MaxRetries - 1)
{
attempts++;
await Task.Delay(TimeSpan.FromSeconds(Math.Pow(2, attempts)), cancellationToken);
}
}
return await _transform(input, cancellationToken);
}
public Task<StageStatistics> GetStatisticsAsync()
{
return Task.FromResult(new StageStatistics
{
StageName = Name,
ItemsProcessed = _metrics.ItemsProcessed,
Errors = _metrics.Errors,
AverageLatency = _metrics.ItemsProcessed > 0
? TimeSpan.FromMilliseconds(_metrics.TotalLatency.TotalMilliseconds / _metrics.ItemsProcessed)
: TimeSpan.Zero,
MemoryUsage = GC.GetTotalMemory(false)
});
}
}
internal class BatchTransformStage<TInput, TOutput> : IPipelineStage
{
private readonly Func<IReadOnlyList<TInput>, CancellationToken, Task<IEnumerable<TOutput>>> _batchTransform;
private readonly ILogger _logger;
private readonly StageMetrics _metrics;
public string Name { get; }
public StageConfiguration Configuration { get; }
public BatchTransformStage(
string name,
Func<IReadOnlyList<TInput>, CancellationToken, Task<IEnumerable<TOutput>>> batchTransform,
StageConfiguration configuration,
ILogger logger)
{
Name = name;
_batchTransform = batchTransform;
Configuration = configuration;
_logger = logger;
_metrics = new StageMetrics();
}
public async Task ProcessAsync(
ChannelReader<object> input,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
var batchSize = Configuration.BufferSize > 0
? Configuration.BufferSize
: SpaceTimeCalculator.CalculateSqrtInterval(context.Configuration.ExpectedItemCount);
var batch = new List<TInput>(batchSize);
var batchTimer = new Timer(_ => ProcessBatch(), null, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1));
try
{
await foreach (var item in input.ReadAllAsync(context.CancellationToken))
{
if (item is TInput typedInput)
{
batch.Add(typedInput);
if (batch.Count >= batchSize)
{
await ProcessBatchAsync(batch, output, context);
batch.Clear();
}
}
}
// Process final batch
if (batch.Count > 0)
{
await ProcessBatchAsync(batch, output, context);
}
}
finally
{
batchTimer?.Dispose();
}
async void ProcessBatch()
{
if (batch.Count > 0)
{
var currentBatch = batch.ToList();
batch.Clear();
await ProcessBatchAsync(currentBatch, output, context);
}
}
}
private async Task ProcessBatchAsync(
List<TInput> batch,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
var stopwatch = Stopwatch.StartNew();
try
{
var results = await _batchTransform(batch.AsReadOnly(), context.CancellationToken);
foreach (var result in results)
{
await output.WriteAsync(result!, context.CancellationToken);
}
_metrics.ItemsProcessed += batch.Count;
_metrics.TotalLatency += stopwatch.Elapsed;
}
catch (Exception ex)
{
_logger.LogError(ex, "Error processing batch in stage {Stage}", Name);
_metrics.Errors += batch.Count;
}
}
public Task<StageStatistics> GetStatisticsAsync()
{
return Task.FromResult(new StageStatistics
{
StageName = Name,
ItemsProcessed = _metrics.ItemsProcessed,
Errors = _metrics.Errors,
AverageLatency = _metrics.ItemsProcessed > 0
? TimeSpan.FromMilliseconds(_metrics.TotalLatency.TotalMilliseconds / _metrics.ItemsProcessed)
: TimeSpan.Zero
});
}
}
internal class FilterStage<T> : IPipelineStage
{
private readonly Func<T, bool> _predicate;
private readonly ILogger _logger;
private readonly StageMetrics _metrics;
private long _itemsFiltered;
public string Name { get; }
public StageConfiguration Configuration { get; }
public FilterStage(
string name,
Func<T, bool> predicate,
StageConfiguration configuration,
ILogger logger)
{
Name = name;
_predicate = predicate;
Configuration = configuration;
_logger = logger;
_metrics = new StageMetrics();
}
public async Task ProcessAsync(
ChannelReader<object> input,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
await foreach (var item in input.ReadAllAsync(context.CancellationToken))
{
if (item is T typedItem)
{
_metrics.ItemsProcessed++;
if (_predicate(typedItem))
{
await output.WriteAsync(item, context.CancellationToken);
}
else
{
Interlocked.Increment(ref _itemsFiltered);
}
}
}
}
public Task<StageStatistics> GetStatisticsAsync()
{
return Task.FromResult(new StageStatistics
{
StageName = Name,
ItemsProcessed = _metrics.ItemsProcessed,
ItemsFiltered = _itemsFiltered,
Errors = _metrics.Errors
});
}
}
internal class CheckpointStage<T> : IPipelineStage
{
private readonly ICheckpointManager _checkpointManager;
private readonly ILogger _logger;
private readonly StageMetrics _metrics;
private long _itemsSinceCheckpoint;
public string Name { get; }
public StageConfiguration Configuration { get; }
public CheckpointStage(
string name,
ICheckpointManager checkpointManager,
StageConfiguration configuration,
ILogger logger)
{
Name = name;
_checkpointManager = checkpointManager;
Configuration = configuration;
_logger = logger;
_metrics = new StageMetrics();
}
public async Task ProcessAsync(
ChannelReader<object> input,
ChannelWriter<object> output,
PipelineExecutionContext context)
{
var checkpointInterval = SpaceTimeCalculator.CalculateSqrtInterval(
context.Configuration.ExpectedItemCount);
var items = new List<T>();
await foreach (var item in input.ReadAllAsync(context.CancellationToken))
{
if (item is T typedItem)
{
items.Add(typedItem);
_metrics.ItemsProcessed++;
_itemsSinceCheckpoint++;
await output.WriteAsync(item, context.CancellationToken);
if (_itemsSinceCheckpoint >= checkpointInterval)
{
await CreateCheckpointAsync(items, context);
_itemsSinceCheckpoint = 0;
}
}
}
// Final checkpoint
if (items.Count > 0)
{
await CreateCheckpointAsync(items, context);
}
}
private async Task CreateCheckpointAsync(List<T> items, PipelineExecutionContext context)
{
try
{
var checkpointData = new PipelineCheckpoint<T>
{
PipelineName = context.PipelineName,
ExecutionId = context.ExecutionId,
StageName = Name,
Timestamp = DateTime.UtcNow,
Items = items.ToList(),
ProcessedCount = _metrics.ItemsProcessed
};
await _checkpointManager.SaveCheckpointAsync(checkpointData, context.CancellationToken);
_logger.LogDebug("Created checkpoint for stage {Stage} with {Count} items",
Name, items.Count);
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to create checkpoint for stage {Stage}", Name);
_metrics.Errors++;
}
}
public Task<StageStatistics> GetStatisticsAsync()
{
return Task.FromResult(new StageStatistics
{
StageName = Name,
ItemsProcessed = _metrics.ItemsProcessed,
Errors = _metrics.Errors
});
}
}
internal class StageMetrics
{
public long ItemsProcessed { get; set; }
public long Errors { get; set; }
public TimeSpan TotalLatency { get; set; }
}
public interface ICheckpointManager
{
Task SaveCheckpointAsync<T>(PipelineCheckpoint<T> checkpoint, CancellationToken cancellationToken = default);
Task<PipelineCheckpoint<T>?> LoadCheckpointAsync<T>(string executionId, string stageName, CancellationToken cancellationToken = default);
}
public class PipelineCheckpoint<T>
{
public string PipelineName { get; set; } = "";
public string ExecutionId { get; set; } = "";
public string StageName { get; set; } = "";
public DateTime Timestamp { get; set; }
public List<T> Items { get; set; } = new();
public long ProcessedCount { get; set; }
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using System.Threading.Tasks.Dataflow;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Scheduling;
/// <summary>
/// Coordinates parallel execution with √n space-time tradeoffs
/// </summary>
public class ParallelCoordinator : IParallelCoordinator
{
private readonly SpaceTimeTaskScheduler _scheduler;
private readonly ILogger<ParallelCoordinator> _logger;
private readonly ParallelOptions _defaultOptions;
public ParallelCoordinator(
SpaceTimeTaskScheduler scheduler,
ILogger<ParallelCoordinator> logger)
{
_scheduler = scheduler ?? throw new ArgumentNullException(nameof(scheduler));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_defaultOptions = new ParallelOptions
{
TaskScheduler = _scheduler,
MaxDegreeOfParallelism = _scheduler.MaximumConcurrencyLevel
};
}
/// <summary>
/// Executes a parallel for loop with √n batching
/// </summary>
public async Task ForAsync<TState>(
int fromInclusive,
int toExclusive,
TState initialState,
Func<int, TState, Task<TState>> body,
Func<TState, TState, TState> combiner,
CancellationToken cancellationToken = default)
{
var count = toExclusive - fromInclusive;
if (count <= 0) return;
// Calculate optimal batch size using √n
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(count);
var batches = new List<(int start, int end)>();
for (int i = fromInclusive; i < toExclusive; i += batchSize)
{
batches.Add((i, Math.Min(i + batchSize, toExclusive)));
}
// Process batches in parallel
var results = new TState[batches.Count];
var options = new ParallelOptions
{
CancellationToken = cancellationToken,
TaskScheduler = _scheduler,
MaxDegreeOfParallelism = _scheduler.MaximumConcurrencyLevel
};
await Parallel.ForEachAsync(
batches.Select((batch, index) => (batch, index)),
options,
async (item, ct) =>
{
var (batch, index) = item;
var localState = initialState;
for (int i = batch.start; i < batch.end && !ct.IsCancellationRequested; i++)
{
localState = await body(i, localState);
}
results[index] = localState;
});
// Combine results
var finalState = initialState;
foreach (var result in results)
{
finalState = combiner(finalState, result);
}
}
/// <summary>
/// Executes a parallel foreach with √n batching and memory awareness
/// </summary>
public async Task<TResult> ForEachAsync<TSource, TResult>(
IEnumerable<TSource> source,
Func<TSource, CancellationToken, Task<TResult>> body,
Func<TResult, TResult, TResult> combiner,
int? maxDegreeOfParallelism = null,
CancellationToken cancellationToken = default)
{
var items = source.ToList();
if (!items.Any()) return default!;
// Create dataflow pipeline with √n buffering
var batchSize = SpaceTimeCalculator.CalculateSqrtInterval(items.Count);
var batchBlock = new BatchBlock<TSource>(batchSize);
var results = new ConcurrentBag<TResult>();
var actionBlock = new ActionBlock<TSource[]>(
async batch =>
{
var batchResults = new List<TResult>();
foreach (var item in batch)
{
if (cancellationToken.IsCancellationRequested)
break;
var result = await body(item, cancellationToken);
batchResults.Add(result);
}
// Combine batch results
if (batchResults.Any())
{
var batchResult = batchResults.Aggregate(combiner);
results.Add(batchResult);
}
},
new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = maxDegreeOfParallelism ?? _scheduler.MaximumConcurrencyLevel,
CancellationToken = cancellationToken,
TaskScheduler = _scheduler
});
batchBlock.LinkTo(actionBlock, new DataflowLinkOptions { PropagateCompletion = true });
// Feed items
foreach (var item in items)
{
await batchBlock.SendAsync(item, cancellationToken);
}
batchBlock.Complete();
await actionBlock.Completion;
// Combine all results
return results.Aggregate(combiner);
}
/// <summary>
/// Executes tasks with memory-aware scheduling
/// </summary>
public async Task<TResult[]> WhenAllWithSchedulingAsync<TResult>(
IEnumerable<Func<CancellationToken, Task<TResult>>> taskFactories,
int maxConcurrency,
CancellationToken cancellationToken = default)
{
var factories = taskFactories.ToList();
var results = new TResult[factories.Count];
var semaphore = new SemaphoreSlim(maxConcurrency);
var tasks = factories.Select(async (factory, index) =>
{
await semaphore.WaitAsync(cancellationToken);
try
{
results[index] = await Task.Factory.StartNew(
async () => await factory(cancellationToken),
cancellationToken,
TaskCreationOptions.None,
_scheduler).Unwrap();
}
finally
{
semaphore.Release();
}
});
await Task.WhenAll(tasks);
return results;
}
/// <summary>
/// Partitions work optimally across available resources
/// </summary>
public async Task<IEnumerable<WorkPartition<T>>> PartitionWorkAsync<T>(
IEnumerable<T> items,
Func<T, long> sizeEstimator,
CancellationToken cancellationToken = default)
{
var itemList = items.ToList();
if (!itemList.Any()) return Enumerable.Empty<WorkPartition<T>>();
// Estimate total size
var totalSize = itemList.Sum(sizeEstimator);
// Calculate optimal partition count using √n
var optimalPartitions = SpaceTimeCalculator.CalculateSqrtInterval(itemList.Count);
var targetPartitionSize = totalSize / optimalPartitions;
var partitions = new List<WorkPartition<T>>();
var currentPartition = new List<T>();
var currentSize = 0L;
foreach (var item in itemList)
{
var itemSize = sizeEstimator(item);
if (currentSize + itemSize > targetPartitionSize && currentPartition.Any())
{
// Start new partition
partitions.Add(new WorkPartition<T>
{
Items = currentPartition.ToList(),
EstimatedSize = currentSize,
Index = partitions.Count
});
currentPartition = new List<T>();
currentSize = 0;
}
currentPartition.Add(item);
currentSize += itemSize;
}
// Add final partition
if (currentPartition.Any())
{
partitions.Add(new WorkPartition<T>
{
Items = currentPartition,
EstimatedSize = currentSize,
Index = partitions.Count
});
}
_logger.LogInformation(
"Partitioned {ItemCount} items into {PartitionCount} partitions",
itemList.Count,
partitions.Count);
return partitions;
}
/// <summary>
/// Creates a memory-aware pipeline
/// </summary>
public IPipeline<TInput, TOutput> CreatePipeline<TInput, TOutput>(
Func<TInput, CancellationToken, Task<TOutput>> transform,
PipelineOptions? options = null)
{
options ??= new PipelineOptions();
var bufferSize = options.BufferSize ??
SpaceTimeCalculator.CalculateSqrtInterval(options.ExpectedItemCount);
var transformBlock = new TransformBlock<TInput, TOutput>(
input => transform(input, CancellationToken.None),
new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = options.MaxConcurrency ?? _scheduler.MaximumConcurrencyLevel,
BoundedCapacity = bufferSize,
TaskScheduler = _scheduler
});
return new DataflowPipeline<TInput, TOutput>(transformBlock, _logger);
}
}
public interface IParallelCoordinator
{
Task ForAsync<TState>(
int fromInclusive,
int toExclusive,
TState initialState,
Func<int, TState, Task<TState>> body,
Func<TState, TState, TState> combiner,
CancellationToken cancellationToken = default);
Task<TResult> ForEachAsync<TSource, TResult>(
IEnumerable<TSource> source,
Func<TSource, CancellationToken, Task<TResult>> body,
Func<TResult, TResult, TResult> combiner,
int? maxDegreeOfParallelism = null,
CancellationToken cancellationToken = default);
Task<TResult[]> WhenAllWithSchedulingAsync<TResult>(
IEnumerable<Func<CancellationToken, Task<TResult>>> taskFactories,
int maxConcurrency,
CancellationToken cancellationToken = default);
Task<IEnumerable<WorkPartition<T>>> PartitionWorkAsync<T>(
IEnumerable<T> items,
Func<T, long> sizeEstimator,
CancellationToken cancellationToken = default);
IPipeline<TInput, TOutput> CreatePipeline<TInput, TOutput>(
Func<TInput, CancellationToken, Task<TOutput>> transform,
PipelineOptions? options = null);
}
public class WorkPartition<T>
{
public List<T> Items { get; set; } = new();
public long EstimatedSize { get; set; }
public int Index { get; set; }
}
public interface IPipeline<TInput, TOutput> : IDisposable
{
Task<TOutput> ProcessAsync(TInput input, CancellationToken cancellationToken = default);
IAsyncEnumerable<TOutput> ProcessManyAsync(IEnumerable<TInput> inputs, CancellationToken cancellationToken = default);
Task CompleteAsync();
}
public class PipelineOptions
{
public int? MaxConcurrency { get; set; }
public int? BufferSize { get; set; }
public int ExpectedItemCount { get; set; } = 1000;
public TimeSpan? Timeout { get; set; }
}
internal class DataflowPipeline<TInput, TOutput> : IPipeline<TInput, TOutput>
{
private readonly TransformBlock<TInput, TOutput> _transformBlock;
private readonly ILogger _logger;
public DataflowPipeline(
TransformBlock<TInput, TOutput> transformBlock,
ILogger logger)
{
_transformBlock = transformBlock;
_logger = logger;
}
public async Task<TOutput> ProcessAsync(TInput input, CancellationToken cancellationToken = default)
{
await _transformBlock.SendAsync(input, cancellationToken);
if (_transformBlock.TryReceive(out var result))
{
return result;
}
// Wait for result
var tcs = new TaskCompletionSource<TOutput>();
using var registration = cancellationToken.Register(() => tcs.TrySetCanceled());
var receiveTask = _transformBlock.ReceiveAsync(cancellationToken);
var completedTask = await Task.WhenAny(receiveTask, tcs.Task);
return await completedTask;
}
public async IAsyncEnumerable<TOutput> ProcessManyAsync(
IEnumerable<TInput> inputs,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
{
// Send all inputs
foreach (var input in inputs)
{
await _transformBlock.SendAsync(input, cancellationToken);
}
_transformBlock.Complete();
// Receive outputs
await foreach (var output in _transformBlock.ReceiveAllAsync(cancellationToken))
{
yield return output;
}
}
public async Task CompleteAsync()
{
_transformBlock.Complete();
await _transformBlock.Completion;
}
public void Dispose()
{
_transformBlock.Complete();
}
}

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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.Caching;
namespace SqrtSpace.SpaceTime.Scheduling;
/// <summary>
/// Memory-aware task scheduler that uses √n space-time tradeoffs
/// </summary>
public class SpaceTimeTaskScheduler : TaskScheduler, IDisposable
{
private readonly IMemoryMonitor _memoryMonitor;
private readonly ILogger<SpaceTimeTaskScheduler> _logger;
private readonly SchedulerOptions _options;
private readonly ConcurrentQueue<ScheduledTask> _highPriorityQueue;
private readonly ConcurrentQueue<ScheduledTask> _normalPriorityQueue;
private readonly ConcurrentQueue<ScheduledTask> _lowPriorityQueue;
private readonly ConcurrentDictionary<int, TaskExecutionContext> _executingTasks;
private readonly SemaphoreSlim _schedulingSemaphore;
private readonly Timer _schedulingTimer;
private readonly Timer _memoryPressureTimer;
private readonly Thread[] _workerThreads;
private readonly CancellationTokenSource _shutdownTokenSource;
private volatile bool _isMemoryConstrained;
public override int MaximumConcurrencyLevel => _options.MaxConcurrency;
public SpaceTimeTaskScheduler(
IMemoryMonitor memoryMonitor,
ILogger<SpaceTimeTaskScheduler> logger,
SchedulerOptions? options = null)
{
_memoryMonitor = memoryMonitor ?? throw new ArgumentNullException(nameof(memoryMonitor));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
_options = options ?? new SchedulerOptions();
_highPriorityQueue = new ConcurrentQueue<ScheduledTask>();
_normalPriorityQueue = new ConcurrentQueue<ScheduledTask>();
_lowPriorityQueue = new ConcurrentQueue<ScheduledTask>();
_executingTasks = new ConcurrentDictionary<int, TaskExecutionContext>();
_schedulingSemaphore = new SemaphoreSlim(_options.MaxConcurrency);
_shutdownTokenSource = new CancellationTokenSource();
// Start worker threads
_workerThreads = new Thread[_options.WorkerThreadCount];
for (int i = 0; i < _workerThreads.Length; i++)
{
_workerThreads[i] = new Thread(WorkerThreadProc)
{
Name = $"SpaceTimeWorker-{i}",
IsBackground = true
};
_workerThreads[i].Start();
}
// Start scheduling timer
_schedulingTimer = new Timer(
ScheduleTasks,
null,
TimeSpan.Zero,
TimeSpan.FromMilliseconds(100));
// Start memory pressure monitoring
_memoryPressureTimer = new Timer(
CheckMemoryPressure,
null,
TimeSpan.Zero,
TimeSpan.FromSeconds(1));
}
protected override void QueueTask(Task task)
{
var scheduledTask = new ScheduledTask
{
Task = task,
QueuedAt = DateTime.UtcNow,
Priority = GetTaskPriority(task),
EstimatedMemory = EstimateTaskMemory(task)
};
// Queue based on priority
switch (scheduledTask.Priority)
{
case TaskPriority.High:
_highPriorityQueue.Enqueue(scheduledTask);
break;
case TaskPriority.Low:
_lowPriorityQueue.Enqueue(scheduledTask);
break;
default:
_normalPriorityQueue.Enqueue(scheduledTask);
break;
}
// Signal that new work is available
_schedulingSemaphore.Release();
}
protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
{
// Only allow inline execution if we're not memory constrained
if (_isMemoryConstrained)
return false;
// Don't inline if we're at capacity
if (_executingTasks.Count >= MaximumConcurrencyLevel)
return false;
return TryExecuteTask(task);
}
protected override IEnumerable<Task> GetScheduledTasks()
{
var tasks = new List<Task>();
foreach (var item in _highPriorityQueue)
tasks.Add(item.Task);
foreach (var item in _normalPriorityQueue)
tasks.Add(item.Task);
foreach (var item in _lowPriorityQueue)
tasks.Add(item.Task);
return tasks;
}
private void WorkerThreadProc()
{
while (!_shutdownTokenSource.Token.IsCancellationRequested)
{
try
{
if (_schedulingSemaphore.Wait(100))
{
ExecuteNextTask();
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in worker thread");
}
}
}
private void ExecuteNextTask()
{
ScheduledTask? scheduledTask = null;
// Try to get task based on priority and memory constraints
if (!_isMemoryConstrained && _highPriorityQueue.TryDequeue(out scheduledTask))
{
// High priority tasks always execute if memory allows
}
else if (ShouldExecuteTask() && TryGetNextTask(out scheduledTask))
{
// Get task based on scheduling policy
}
if (scheduledTask != null)
{
var context = new TaskExecutionContext
{
Task = scheduledTask.Task,
StartTime = DateTime.UtcNow,
ThreadId = Environment.CurrentManagedThreadId,
InitialMemory = GC.GetTotalMemory(false)
};
_executingTasks[scheduledTask.Task.Id] = context;
try
{
TryExecuteTask(scheduledTask.Task);
}
finally
{
context.EndTime = DateTime.UtcNow;
context.FinalMemory = GC.GetTotalMemory(false);
_executingTasks.TryRemove(scheduledTask.Task.Id, out _);
LogTaskExecution(scheduledTask, context);
}
}
}
private bool ShouldExecuteTask()
{
// Check concurrency limit
if (_executingTasks.Count >= MaximumConcurrencyLevel)
return false;
// Check memory constraints
if (_isMemoryConstrained)
{
// Only execute if we have very few tasks running
return _executingTasks.Count < MaximumConcurrencyLevel / 2;
}
return true;
}
private bool TryGetNextTask(out ScheduledTask? task)
{
task = null;
// Use √n strategy for task selection
var totalTasks = _normalPriorityQueue.Count + _lowPriorityQueue.Count;
if (totalTasks == 0)
return false;
var sqrtN = SpaceTimeCalculator.CalculateSqrtInterval(totalTasks);
// Sample tasks to find best candidate
var candidates = new List<ScheduledTask>();
// Sample from normal priority
for (int i = 0; i < Math.Min(sqrtN, _normalPriorityQueue.Count); i++)
{
if (_normalPriorityQueue.TryPeek(out var candidate))
candidates.Add(candidate);
}
// Sample from low priority
for (int i = 0; i < Math.Min(sqrtN / 2, _lowPriorityQueue.Count); i++)
{
if (_lowPriorityQueue.TryPeek(out var candidate))
candidates.Add(candidate);
}
if (candidates.Any())
{
// Select task with best score
task = candidates.OrderByDescending(t => CalculateTaskScore(t)).First();
// Remove selected task from its queue
if (task.Priority == TaskPriority.Normal)
_normalPriorityQueue.TryDequeue(out _);
else
_lowPriorityQueue.TryDequeue(out _);
return true;
}
return false;
}
private double CalculateTaskScore(ScheduledTask task)
{
var waitTime = (DateTime.UtcNow - task.QueuedAt).TotalMilliseconds;
var priorityWeight = task.Priority switch
{
TaskPriority.High => 3.0,
TaskPriority.Normal => 1.0,
TaskPriority.Low => 0.3,
_ => 1.0
};
// Favor tasks that have waited longer and have higher priority
// Penalize tasks with high memory requirements when constrained
var memoryPenalty = _isMemoryConstrained ? task.EstimatedMemory / 1024.0 / 1024.0 : 0;
return (waitTime * priorityWeight) - memoryPenalty;
}
private void ScheduleTasks(object? state)
{
try
{
// Adaptive scheduling based on system state
var executingCount = _executingTasks.Count;
var queuedCount = _highPriorityQueue.Count + _normalPriorityQueue.Count + _lowPriorityQueue.Count;
if (queuedCount > 0 && executingCount < MaximumConcurrencyLevel)
{
var toSchedule = Math.Min(
MaximumConcurrencyLevel - executingCount,
SpaceTimeCalculator.CalculateSqrtInterval(queuedCount)
);
for (int i = 0; i < toSchedule; i++)
{
_schedulingSemaphore.Release();
}
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error in scheduling timer");
}
}
private async void CheckMemoryPressure(object? state)
{
try
{
var pressure = await _memoryMonitor.GetMemoryPressureAsync();
_isMemoryConstrained = pressure >= MemoryPressureLevel.High;
if (_isMemoryConstrained)
{
_logger.LogWarning("Memory pressure detected, reducing task execution");
// Consider suspending low priority tasks
SuspendLowPriorityTasks();
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error checking memory pressure");
}
}
private void SuspendLowPriorityTasks()
{
var lowPriorityTasks = _executingTasks.Values
.Where(ctx => GetTaskPriority(ctx.Task) == TaskPriority.Low)
.ToList();
foreach (var context in lowPriorityTasks)
{
// Request cancellation if task supports it
if (context.Task.AsyncState is CancellationTokenSource cts)
{
cts.Cancel();
}
}
}
private TaskPriority GetTaskPriority(Task task)
{
// Check for priority in task state or custom properties
if (task.AsyncState is IScheduledTask scheduled)
{
return scheduled.Priority;
}
return TaskPriority.Normal;
}
private long EstimateTaskMemory(Task task)
{
// Estimate based on task type or state
if (task.AsyncState is IScheduledTask scheduled)
{
return scheduled.EstimatedMemoryUsage;
}
// Default estimate
return 1024 * 1024; // 1MB
}
private void LogTaskExecution(ScheduledTask scheduledTask, TaskExecutionContext context)
{
var duration = context.EndTime!.Value - context.StartTime;
var memoryDelta = context.FinalMemory - context.InitialMemory;
_logger.LogDebug(
"Task {TaskId} completed. Priority: {Priority}, Duration: {Duration}ms, Memory: {MemoryDelta} bytes",
scheduledTask.Task.Id,
scheduledTask.Priority,
duration.TotalMilliseconds,
memoryDelta);
}
public void Dispose()
{
_shutdownTokenSource.Cancel();
_schedulingTimer?.Dispose();
_memoryPressureTimer?.Dispose();
// Wait for worker threads to complete
foreach (var thread in _workerThreads)
{
thread.Join(TimeSpan.FromSeconds(5));
}
_schedulingSemaphore?.Dispose();
_shutdownTokenSource?.Dispose();
}
}
public class SchedulerOptions
{
public int MaxConcurrency { get; set; } = Environment.ProcessorCount;
public int WorkerThreadCount { get; set; } = Environment.ProcessorCount;
public TimeSpan TaskTimeout { get; set; } = TimeSpan.FromMinutes(5);
public bool EnableMemoryAwareScheduling { get; set; } = true;
public long MemoryThreshold { get; set; } = 1024L * 1024 * 1024; // 1GB
}
public interface IScheduledTask
{
TaskPriority Priority { get; }
long EstimatedMemoryUsage { get; }
}
public enum TaskPriority
{
Low = 0,
Normal = 1,
High = 2
}
internal class ScheduledTask
{
public Task Task { get; set; } = null!;
public DateTime QueuedAt { get; set; }
public TaskPriority Priority { get; set; }
public long EstimatedMemory { get; set; }
}
internal class TaskExecutionContext
{
public Task Task { get; set; } = null!;
public DateTime StartTime { get; set; }
public DateTime? EndTime { get; set; }
public int ThreadId { get; set; }
public long InitialMemory { get; set; }
public long FinalMemory { get; set; }
}
/// <summary>
/// Factory for creating memory-aware tasks
/// </summary>
public class SpaceTimeTaskFactory : TaskFactory
{
private readonly SpaceTimeTaskScheduler _scheduler;
public SpaceTimeTaskFactory(SpaceTimeTaskScheduler scheduler)
: base(scheduler)
{
_scheduler = scheduler;
}
public Task StartNew<TState>(
Action<TState> action,
TState state,
TaskPriority priority,
long estimatedMemory,
CancellationToken cancellationToken = default)
{
var scheduledState = new ScheduledTaskState<TState>
{
State = state,
Priority = priority,
EstimatedMemoryUsage = estimatedMemory
};
return StartNew(
s => action(((ScheduledTaskState<TState>)s!).State),
scheduledState,
cancellationToken,
TaskCreationOptions.None,
_scheduler);
}
public Task<TResult> StartNew<TState, TResult>(
Func<TState, TResult> function,
TState state,
TaskPriority priority,
long estimatedMemory,
CancellationToken cancellationToken = default)
{
var scheduledState = new ScheduledTaskState<TState>
{
State = state,
Priority = priority,
EstimatedMemoryUsage = estimatedMemory
};
return StartNew(
s => function(((ScheduledTaskState<TState>)s!).State),
scheduledState,
cancellationToken,
TaskCreationOptions.None,
_scheduler);
}
private class ScheduledTaskState<T> : IScheduledTask
{
public T State { get; set; } = default!;
public TaskPriority Priority { get; set; }
public long EstimatedMemoryUsage { get; set; }
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory-aware task scheduling and parallel coordination for SpaceTime</Description>
<PackageTags>scheduling;parallel;tasks;memory;spacetime;coordinator</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Scheduling</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
<PackageReference Include="System.Threading.Tasks.Dataflow" Version="9.0.7" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
<ProjectReference Include="..\SqrtSpace.SpaceTime.Caching\SqrtSpace.SpaceTime.Caching.csproj" />
</ItemGroup>
</Project>

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using System;
using System.IO;
using System.IO.Compression;
using System.Threading;
using System.Threading.Tasks;
using K4os.Compression.LZ4;
using K4os.Compression.LZ4.Streams;
namespace SqrtSpace.SpaceTime.Serialization;
/// <summary>
/// Base interface for compression providers
/// </summary>
internal interface ICompressionProvider
{
Task CompressAsync(Stream source, Stream destination, int level, CancellationToken cancellationToken = default);
Task DecompressAsync(Stream source, Stream destination, CancellationToken cancellationToken = default);
}
/// <summary>
/// LZ4 compression provider for fast compression
/// </summary>
internal class LZ4CompressionProvider : ICompressionProvider
{
public async Task CompressAsync(Stream source, Stream destination, int level, CancellationToken cancellationToken = default)
{
var settings = new LZ4EncoderSettings
{
CompressionLevel = MapCompressionLevel(level),
BlockSize = 65536, // 64KB
ContentChecksum = true,
BlockChecksum = false,
// Dictionary = null // Removed as it's read-only
};
using var encoder = LZ4Stream.Encode(destination, settings, leaveOpen: true);
await source.CopyToAsync(encoder, 81920, cancellationToken); // 80KB buffer
await encoder.FlushAsync(cancellationToken);
}
public async Task DecompressAsync(Stream source, Stream destination, CancellationToken cancellationToken = default)
{
var settings = new LZ4DecoderSettings
{
ExtraMemory = 0
};
using var decoder = LZ4Stream.Decode(source, settings, leaveOpen: true);
await decoder.CopyToAsync(destination, 81920, cancellationToken);
}
private static LZ4Level MapCompressionLevel(int level)
{
return level switch
{
<= 3 => LZ4Level.L00_FAST,
<= 6 => LZ4Level.L03_HC,
<= 8 => LZ4Level.L06_HC,
_ => LZ4Level.L09_HC
};
}
}
/// <summary>
/// GZip compression provider for better compression ratio
/// </summary>
internal class GZipCompressionProvider : ICompressionProvider
{
public async Task CompressAsync(Stream source, Stream destination, int level, CancellationToken cancellationToken = default)
{
var compressionLevel = level switch
{
<= 3 => CompressionLevel.Fastest,
<= 6 => CompressionLevel.Optimal,
_ => CompressionLevel.SmallestSize
};
using var gzipStream = new GZipStream(destination, compressionLevel, leaveOpen: true);
await source.CopyToAsync(gzipStream, 81920, cancellationToken);
await gzipStream.FlushAsync();
}
public async Task DecompressAsync(Stream source, Stream destination, CancellationToken cancellationToken = default)
{
using var gzipStream = new GZipStream(source, CompressionMode.Decompress, leaveOpen: true);
await gzipStream.CopyToAsync(destination, 81920, cancellationToken);
}
}
/// <summary>
/// Brotli compression provider for best compression ratio
/// </summary>
internal class BrotliCompressionProvider : ICompressionProvider
{
public async Task CompressAsync(Stream source, Stream destination, int level, CancellationToken cancellationToken = default)
{
var compressionLevel = level switch
{
<= 3 => CompressionLevel.Fastest,
<= 6 => CompressionLevel.Optimal,
_ => CompressionLevel.SmallestSize
};
using var brotliStream = new BrotliStream(destination, compressionLevel, leaveOpen: true);
await source.CopyToAsync(brotliStream, 81920, cancellationToken);
await brotliStream.FlushAsync();
}
public async Task DecompressAsync(Stream source, Stream destination, CancellationToken cancellationToken = default)
{
using var brotliStream = new BrotliStream(source, CompressionMode.Decompress, leaveOpen: true);
await brotliStream.CopyToAsync(destination, 81920, cancellationToken);
}
}
/// <summary>
/// Adaptive compression provider that selects algorithm based on data characteristics
/// </summary>
internal class AdaptiveCompressionProvider : ICompressionProvider
{
private readonly LZ4CompressionProvider _lz4Provider;
private readonly GZipCompressionProvider _gzipProvider;
private readonly BrotliCompressionProvider _brotliProvider;
public AdaptiveCompressionProvider()
{
_lz4Provider = new LZ4CompressionProvider();
_gzipProvider = new GZipCompressionProvider();
_brotliProvider = new BrotliCompressionProvider();
}
public async Task CompressAsync(Stream source, Stream destination, int level, CancellationToken cancellationToken = default)
{
// Analyze data characteristics
var dataSize = source.Length;
var provider = SelectProvider(dataSize, level);
// Write compression type header
destination.WriteByte((byte)provider);
// Compress with selected provider
switch (provider)
{
case CompressionType.LZ4:
await _lz4Provider.CompressAsync(source, destination, level, cancellationToken);
break;
case CompressionType.GZip:
await _gzipProvider.CompressAsync(source, destination, level, cancellationToken);
break;
case CompressionType.Brotli:
await _brotliProvider.CompressAsync(source, destination, level, cancellationToken);
break;
}
}
public async Task DecompressAsync(Stream source, Stream destination, CancellationToken cancellationToken = default)
{
// Read compression type header
var typeByte = source.ReadByte();
if (typeByte == -1)
throw new InvalidOperationException("Invalid compression header");
var compressionType = (CompressionType)typeByte;
// Decompress with appropriate provider
switch (compressionType)
{
case CompressionType.LZ4:
await _lz4Provider.DecompressAsync(source, destination, cancellationToken);
break;
case CompressionType.GZip:
await _gzipProvider.DecompressAsync(source, destination, cancellationToken);
break;
case CompressionType.Brotli:
await _brotliProvider.DecompressAsync(source, destination, cancellationToken);
break;
default:
throw new NotSupportedException($"Compression type {compressionType} is not supported");
}
}
private CompressionType SelectProvider(long dataSize, int level)
{
// For small data or when speed is critical, use LZ4
if (dataSize < 100_000 || level <= 3)
return CompressionType.LZ4;
// For medium data with balanced requirements, use GZip
if (dataSize < 10_000_000 || level <= 6)
return CompressionType.GZip;
// For large data where compression ratio is important, use Brotli
return CompressionType.Brotli;
}
private enum CompressionType : byte
{
LZ4 = 1,
GZip = 2,
Brotli = 3
}
}

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using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Options;
using SqrtSpace.SpaceTime.Serialization.Streaming;
namespace SqrtSpace.SpaceTime.Serialization.Extensions;
/// <summary>
/// Extension methods for dependency injection
/// </summary>
public static class ServiceCollectionExtensions
{
/// <summary>
/// Add SpaceTime serialization services
/// </summary>
public static IServiceCollection AddSpaceTimeSerialization(
this IServiceCollection services,
Action<SerializationBuilder>? configure = null)
{
var builder = new SerializationBuilder(services);
configure?.Invoke(builder);
// Register core serializer
services.TryAddSingleton<ISpaceTimeSerializer, SpaceTimeSerializer>();
// Register streaming serializers
services.TryAddTransient(typeof(StreamingSerializer<>));
return services;
}
}
/// <summary>
/// Builder for configuring serialization
/// </summary>
public class SerializationBuilder
{
private readonly IServiceCollection _services;
public SerializationBuilder(IServiceCollection services)
{
_services = services;
}
/// <summary>
/// Configure default serialization options
/// </summary>
public SerializationBuilder ConfigureDefaults(Action<SerializationOptions> configure)
{
_services.Configure<SerializationOptions>(configure);
return this;
}
/// <summary>
/// Add custom type converter
/// </summary>
public SerializationBuilder AddTypeConverter<T>(ITypeConverter converter)
{
_services.Configure<SerializationOptions>(options =>
{
options.TypeConverters[typeof(T)] = converter;
});
return this;
}
/// <summary>
/// Use specific serialization format as default
/// </summary>
public SerializationBuilder UseFormat(SerializationFormat format)
{
_services.Configure<SerializationOptions>(options =>
{
options.Format = format;
});
return this;
}
/// <summary>
/// Configure compression settings
/// </summary>
public SerializationBuilder ConfigureCompression(
bool enable = true,
int level = 6)
{
_services.Configure<SerializationOptions>(options =>
{
options.EnableCompression = enable;
options.CompressionLevel = level;
});
return this;
}
/// <summary>
/// Configure memory limits
/// </summary>
public SerializationBuilder ConfigureMemoryLimits(long maxMemoryUsage)
{
_services.Configure<SerializationOptions>(options =>
{
options.MaxMemoryUsage = maxMemoryUsage;
});
return this;
}
}

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using System;
using System.IO;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using MessagePack;
using ProtoBuf;
namespace SqrtSpace.SpaceTime.Serialization;
/// <summary>
/// Base interface for serialization providers
/// </summary>
internal interface ISerializationProvider
{
Task SerializeAsync<T>(T obj, Stream stream, CancellationToken cancellationToken = default);
Task<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default);
}
/// <summary>
/// JSON serialization provider using System.Text.Json
/// </summary>
internal class JsonSerializationProvider : ISerializationProvider
{
private readonly JsonSerializerOptions _options;
public JsonSerializationProvider()
{
_options = new JsonSerializerOptions
{
PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
WriteIndented = false,
DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull,
Converters = { new System.Text.Json.Serialization.JsonStringEnumConverter() }
};
}
public async Task SerializeAsync<T>(T obj, Stream stream, CancellationToken cancellationToken = default)
{
await JsonSerializer.SerializeAsync(stream, obj, _options, cancellationToken);
}
public async Task<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
{
return await JsonSerializer.DeserializeAsync<T>(stream, _options, cancellationToken)
?? throw new InvalidOperationException("Deserialization resulted in null");
}
}
/// <summary>
/// MessagePack serialization provider
/// </summary>
internal class MessagePackSerializationProvider : ISerializationProvider
{
private readonly MessagePackSerializerOptions _options;
public MessagePackSerializationProvider()
{
_options = MessagePackSerializerOptions.Standard
.WithCompression(MessagePackCompression.Lz4BlockArray)
.WithAllowAssemblyVersionMismatch(true);
}
public async Task SerializeAsync<T>(T obj, Stream stream, CancellationToken cancellationToken = default)
{
await MessagePackSerializer.SerializeAsync(stream, obj, _options, cancellationToken);
}
public async Task<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
{
return await MessagePackSerializer.DeserializeAsync<T>(stream, _options, cancellationToken);
}
}
/// <summary>
/// ProtoBuf serialization provider
/// </summary>
internal class ProtoBufSerializationProvider : ISerializationProvider
{
public Task SerializeAsync<T>(T obj, Stream stream, CancellationToken cancellationToken = default)
{
Serializer.Serialize(stream, obj);
return Task.CompletedTask;
}
public Task<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
{
var result = Serializer.Deserialize<T>(stream);
return Task.FromResult(result);
}
}
/// <summary>
/// Binary serialization provider for primitive types
/// </summary>
internal class BinarySerializationProvider : ISerializationProvider
{
public async Task SerializeAsync<T>(T obj, Stream stream, CancellationToken cancellationToken = default)
{
using var writer = new BinaryWriter(stream, System.Text.Encoding.UTF8, leaveOpen: true);
switch (obj)
{
case string str:
writer.Write(str);
break;
case int intVal:
writer.Write(intVal);
break;
case long longVal:
writer.Write(longVal);
break;
case double doubleVal:
writer.Write(doubleVal);
break;
case bool boolVal:
writer.Write(boolVal);
break;
case byte[] bytes:
writer.Write(bytes.Length);
writer.Write(bytes);
break;
default:
throw new NotSupportedException($"Binary serialization not supported for type {typeof(T)}");
}
await stream.FlushAsync(cancellationToken);
}
public Task<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
{
using var reader = new BinaryReader(stream, System.Text.Encoding.UTF8, leaveOpen: true);
object result = typeof(T).Name switch
{
nameof(String) => reader.ReadString(),
nameof(Int32) => reader.ReadInt32(),
nameof(Int64) => reader.ReadInt64(),
nameof(Double) => reader.ReadDouble(),
nameof(Boolean) => reader.ReadBoolean(),
"Byte[]" => reader.ReadBytes(reader.ReadInt32()),
_ => throw new NotSupportedException($"Binary deserialization not supported for type {typeof(T)}")
};
return Task.FromResult((T)result);
}
}

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using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO;
using System.IO.Pipelines;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.ObjectPool;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Serialization;
/// <summary>
/// Memory-efficient serializer with √n chunking
/// </summary>
public interface ISpaceTimeSerializer
{
/// <summary>
/// Serialize object to stream with memory-efficient chunking
/// </summary>
Task SerializeAsync<T>(T obj, Stream stream, SerializationOptions? options = null, CancellationToken cancellationToken = default);
/// <summary>
/// Deserialize object from stream with memory-efficient chunking
/// </summary>
Task<T> DeserializeAsync<T>(Stream stream, SerializationOptions? options = null, CancellationToken cancellationToken = default);
/// <summary>
/// Serialize collection with √n batching
/// </summary>
Task SerializeCollectionAsync<T>(IEnumerable<T> items, Stream stream, SerializationOptions? options = null, CancellationToken cancellationToken = default);
/// <summary>
/// Deserialize collection with streaming
/// </summary>
IAsyncEnumerable<T> DeserializeCollectionAsync<T>(Stream stream, SerializationOptions? options = null, CancellationToken cancellationToken = default);
/// <summary>
/// Get estimated serialized size
/// </summary>
long EstimateSerializedSize<T>(T obj);
}
/// <summary>
/// Serialization options
/// </summary>
public class SerializationOptions
{
/// <summary>
/// Serialization format
/// </summary>
public SerializationFormat Format { get; set; } = SerializationFormat.MessagePack;
/// <summary>
/// Enable compression
/// </summary>
public bool EnableCompression { get; set; } = true;
/// <summary>
/// Compression level (1-9)
/// </summary>
public int CompressionLevel { get; set; } = 6;
/// <summary>
/// Buffer size for streaming (0 for auto √n)
/// </summary>
public int BufferSize { get; set; } = 0;
/// <summary>
/// Enable checkpointing for large data
/// </summary>
public bool EnableCheckpointing { get; set; } = true;
/// <summary>
/// Checkpoint interval (0 for auto √n)
/// </summary>
public int CheckpointInterval { get; set; } = 0;
/// <summary>
/// Maximum memory usage for buffering
/// </summary>
public long MaxMemoryUsage { get; set; } = 104857600; // 100 MB
/// <summary>
/// Custom type converters
/// </summary>
public Dictionary<Type, ITypeConverter> TypeConverters { get; set; } = new();
}
public enum SerializationFormat
{
Json,
MessagePack,
ProtoBuf,
Binary
}
/// <summary>
/// Custom type converter interface
/// </summary>
public interface ITypeConverter
{
byte[] Serialize(object obj);
object Deserialize(byte[] data, Type targetType);
}
/// <summary>
/// Default implementation of SpaceTime serializer
/// </summary>
public class SpaceTimeSerializer : ISpaceTimeSerializer
{
private readonly ObjectPool<MemoryStream> _streamPool;
private readonly ArrayPool<byte> _bufferPool;
private readonly ISerializationProvider _jsonProvider;
private readonly ISerializationProvider _messagePackProvider;
private readonly ISerializationProvider _protoBufProvider;
private readonly ICompressionProvider _compressionProvider;
public SpaceTimeSerializer()
{
_streamPool = new DefaultObjectPool<MemoryStream>(new MemoryStreamPooledObjectPolicy());
_bufferPool = ArrayPool<byte>.Shared;
_jsonProvider = new JsonSerializationProvider();
_messagePackProvider = new MessagePackSerializationProvider();
_protoBufProvider = new ProtoBufSerializationProvider();
_compressionProvider = new LZ4CompressionProvider();
}
public async Task SerializeAsync<T>(
T obj,
Stream stream,
SerializationOptions? options = null,
CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var provider = GetSerializationProvider(options.Format);
using var memoryStream = _streamPool.Get();
try
{
// Serialize to memory first
await provider.SerializeAsync(obj, memoryStream, cancellationToken);
memoryStream.Position = 0;
// Apply compression if enabled
if (options.EnableCompression)
{
await CompressAndWriteAsync(memoryStream, stream, options, cancellationToken);
}
else
{
await CopyWithChunkingAsync(memoryStream, stream, options, cancellationToken);
}
}
finally
{
_streamPool.Return(memoryStream);
}
}
public async Task<T> DeserializeAsync<T>(
Stream stream,
SerializationOptions? options = null,
CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var provider = GetSerializationProvider(options.Format);
using var memoryStream = _streamPool.Get();
try
{
// Decompress if needed
if (options.EnableCompression)
{
await DecompressAsync(stream, memoryStream, options, cancellationToken);
}
else
{
await CopyWithChunkingAsync(stream, memoryStream, options, cancellationToken);
}
memoryStream.Position = 0;
return await provider.DeserializeAsync<T>(memoryStream, cancellationToken);
}
finally
{
_streamPool.Return(memoryStream);
}
}
public async Task SerializeCollectionAsync<T>(
IEnumerable<T> items,
Stream stream,
SerializationOptions? options = null,
CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var provider = GetSerializationProvider(options.Format);
// Calculate batch size
var estimatedCount = items is ICollection<T> collection ? collection.Count : 10000;
var batchSize = options.BufferSize > 0
? options.BufferSize
: SpaceTimeCalculator.CalculateSqrtInterval(estimatedCount);
// Create pipe for streaming serialization
var pipe = new Pipe();
// Start writer task
var writerTask = Task.Run(async () =>
{
try
{
var batch = new List<T>(batchSize);
var itemCount = 0;
foreach (var item in items)
{
cancellationToken.ThrowIfCancellationRequested();
batch.Add(item);
itemCount++;
if (batch.Count >= batchSize)
{
await WriteBatchAsync(batch, pipe.Writer, provider, cancellationToken);
batch.Clear();
}
}
// Write final batch
if (batch.Count > 0)
{
await WriteBatchAsync(batch, pipe.Writer, provider, cancellationToken);
}
// Write end marker
await WriteEndMarkerAsync(pipe.Writer, cancellationToken);
}
finally
{
await pipe.Writer.CompleteAsync();
}
}, cancellationToken);
// Read from pipe and write to stream
if (options.EnableCompression)
{
await _compressionProvider.CompressAsync(
pipe.Reader.AsStream(),
stream,
options.CompressionLevel,
cancellationToken);
}
else
{
await pipe.Reader.CopyToAsync(stream, cancellationToken);
}
await writerTask;
}
public async IAsyncEnumerable<T> DeserializeCollectionAsync<T>(
Stream stream,
SerializationOptions? options = null,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var provider = GetSerializationProvider(options.Format);
// Create pipe for streaming deserialization
var pipe = new Pipe();
// Start reader task
var readerTask = Task.Run(async () =>
{
try
{
if (options.EnableCompression)
{
await _compressionProvider.DecompressAsync(
stream,
pipe.Writer.AsStream(),
cancellationToken);
}
else
{
await stream.CopyToAsync(pipe.Writer.AsStream(), cancellationToken);
}
}
finally
{
await pipe.Writer.CompleteAsync();
}
}, cancellationToken);
// Read batches from pipe
var reader = pipe.Reader;
while (!cancellationToken.IsCancellationRequested)
{
var batch = await ReadBatchAsync<T>(reader, provider, cancellationToken);
if (batch == null)
break; // End marker reached
foreach (var item in batch)
{
yield return item;
}
}
await readerTask;
}
public long EstimateSerializedSize<T>(T obj)
{
if (obj == null)
return 0;
// Use a heuristic based on object type
return obj switch
{
string str => str.Length * 2 + 24, // UTF-16 + overhead
byte[] bytes => bytes.Length + 24,
ICollection<object> collection => collection.Count * 64, // Rough estimate
_ => 256 // Default estimate
};
}
private ISerializationProvider GetSerializationProvider(SerializationFormat format)
{
return format switch
{
SerializationFormat.Json => _jsonProvider,
SerializationFormat.MessagePack => _messagePackProvider,
SerializationFormat.ProtoBuf => _protoBufProvider,
_ => throw new NotSupportedException($"Format {format} is not supported")
};
}
private async Task CopyWithChunkingAsync(
Stream source,
Stream destination,
SerializationOptions options,
CancellationToken cancellationToken)
{
var bufferSize = options.BufferSize > 0
? options.BufferSize
: SpaceTimeCalculator.CalculateSqrtInterval(source.Length);
var buffer = _bufferPool.Rent(bufferSize);
try
{
int bytesRead;
while ((bytesRead = await source.ReadAsync(buffer, 0, bufferSize, cancellationToken)) > 0)
{
await destination.WriteAsync(buffer, 0, bytesRead, cancellationToken);
}
}
finally
{
_bufferPool.Return(buffer);
}
}
private async Task CompressAndWriteAsync(
Stream source,
Stream destination,
SerializationOptions options,
CancellationToken cancellationToken)
{
await _compressionProvider.CompressAsync(
source,
destination,
options.CompressionLevel,
cancellationToken);
}
private async Task DecompressAsync(
Stream source,
Stream destination,
SerializationOptions options,
CancellationToken cancellationToken)
{
await _compressionProvider.DecompressAsync(source, destination, cancellationToken);
}
private async Task WriteBatchAsync<T>(
List<T> batch,
PipeWriter writer,
ISerializationProvider provider,
CancellationToken cancellationToken)
{
using var memoryStream = _streamPool.Get();
try
{
// Write batch header
await WriteBatchHeaderAsync(writer, batch.Count, cancellationToken);
// Serialize batch
await provider.SerializeAsync(batch, memoryStream, cancellationToken);
memoryStream.Position = 0;
// Write to pipe
var buffer = writer.GetMemory((int)memoryStream.Length);
var bytesRead = await memoryStream.ReadAsync(buffer, cancellationToken);
writer.Advance(bytesRead);
await writer.FlushAsync(cancellationToken);
}
finally
{
_streamPool.Return(memoryStream);
}
}
private async Task WriteBatchHeaderAsync(
PipeWriter writer,
int itemCount,
CancellationToken cancellationToken)
{
var header = BitConverter.GetBytes(itemCount);
await writer.WriteAsync(header, cancellationToken);
}
private async Task WriteEndMarkerAsync(PipeWriter writer, CancellationToken cancellationToken)
{
var endMarker = BitConverter.GetBytes(-1);
await writer.WriteAsync(endMarker, cancellationToken);
}
private async Task<List<T>?> ReadBatchAsync<T>(
PipeReader reader,
ISerializationProvider provider,
CancellationToken cancellationToken)
{
// Read batch header
var headerResult = await reader.ReadAsync(cancellationToken);
if (headerResult.Buffer.Length < 4)
return null;
var itemCount = BitConverter.ToInt32(headerResult.Buffer.Slice(0, 4).ToArray(), 0);
reader.AdvanceTo(headerResult.Buffer.GetPosition(4));
if (itemCount == -1)
return null; // End marker
// Read batch data
using var memoryStream = _streamPool.Get();
try
{
var dataResult = await reader.ReadAsync(cancellationToken);
await memoryStream.WriteAsync(dataResult.Buffer.ToArray(), cancellationToken);
reader.AdvanceTo(dataResult.Buffer.End);
memoryStream.Position = 0;
return await provider.DeserializeAsync<List<T>>(memoryStream, cancellationToken);
}
finally
{
_streamPool.Return(memoryStream);
}
}
}
/// <summary>
/// Memory stream pooled object policy
/// </summary>
internal class MemoryStreamPooledObjectPolicy : IPooledObjectPolicy<MemoryStream>
{
public MemoryStream Create()
{
return new MemoryStream();
}
public bool Return(MemoryStream obj)
{
if (obj.Length > 1024 * 1024) // Don't pool streams larger than 1MB
return false;
obj.Position = 0;
obj.SetLength(0);
return true;
}
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>Memory-efficient serialization with √n chunking and streaming</Description>
<PackageTags>serialization;streaming;chunking;compression;spacetime</PackageTags>
<PackageId>SqrtSpace.SpaceTime.Serialization</PackageId>
<IsPackable>true</IsPackable>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="System.IO.Pipelines" Version="9.0.7" />
<PackageReference Include="System.Text.Json" Version="9.0.7" />
<PackageReference Include="MessagePack" Version="3.1.4" />
<PackageReference Include="protobuf-net" Version="3.2.52" />
<PackageReference Include="K4os.Compression.LZ4.Streams" Version="1.3.8" />
<PackageReference Include="Microsoft.Extensions.ObjectPool" Version="9.0.7" />
<PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="9.0.7" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\SqrtSpace.SpaceTime.Core\SqrtSpace.SpaceTime.Core.csproj" />
</ItemGroup>
</Project>

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using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using SqrtSpace.SpaceTime.Core;
namespace SqrtSpace.SpaceTime.Serialization.Streaming;
/// <summary>
/// Streaming serializer for large datasets with √n memory usage
/// </summary>
public class StreamingSerializer<T>
{
private readonly ISpaceTimeSerializer _serializer;
private readonly ArrayPool<byte> _bufferPool;
private readonly int _defaultChunkSize;
public StreamingSerializer(ISpaceTimeSerializer serializer)
{
_serializer = serializer ?? throw new ArgumentNullException(nameof(serializer));
_bufferPool = ArrayPool<byte>.Shared;
_defaultChunkSize = 65536; // 64KB default
}
/// <summary>
/// Serialize large collection to file with minimal memory usage
/// </summary>
public async Task SerializeToFileAsync(
IAsyncEnumerable<T> items,
string filePath,
SerializationOptions? options = null,
IProgress<SerializationProgress>? progress = null,
CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
using var fileStream = new FileStream(
filePath,
FileMode.Create,
FileAccess.Write,
FileShare.None,
bufferSize: 4096,
useAsync: true);
await SerializeToStreamAsync(items, fileStream, options, progress, cancellationToken);
}
/// <summary>
/// Deserialize large file with streaming
/// </summary>
public async IAsyncEnumerable<T> DeserializeFromFileAsync(
string filePath,
SerializationOptions? options = null,
IProgress<SerializationProgress>? progress = null,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
using var fileStream = new FileStream(
filePath,
FileMode.Open,
FileAccess.Read,
FileShare.Read,
bufferSize: 4096,
useAsync: true);
await foreach (var item in DeserializeFromStreamAsync(fileStream, options, progress, cancellationToken))
{
yield return item;
}
}
/// <summary>
/// Serialize to stream with progress reporting
/// </summary>
public async Task SerializeToStreamAsync(
IAsyncEnumerable<T> items,
Stream stream,
SerializationOptions? options = null,
IProgress<SerializationProgress>? progress = null,
CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var progressData = new SerializationProgress();
var checkpointInterval = options.CheckpointInterval > 0
? options.CheckpointInterval
: SpaceTimeCalculator.CalculateSqrtInterval(1000000); // Default for 1M items
var buffer = new List<T>(checkpointInterval);
var checkpointManager = options.EnableCheckpointing ? new StreamCheckpointManager() : null;
try
{
await foreach (var item in items.WithCancellation(cancellationToken))
{
buffer.Add(item);
progressData.ItemsProcessed++;
if (buffer.Count >= checkpointInterval)
{
await WriteBufferAsync(stream, buffer, options, cancellationToken);
if (checkpointManager != null)
{
await checkpointManager.CreateCheckpointAsync(
stream.Position,
progressData.ItemsProcessed,
cancellationToken);
}
progressData.BytesProcessed = stream.Position;
progress?.Report(progressData);
buffer.Clear();
}
}
// Write remaining items
if (buffer.Count > 0)
{
await WriteBufferAsync(stream, buffer, options, cancellationToken);
progressData.BytesProcessed = stream.Position;
progress?.Report(progressData);
}
// Write end marker
await WriteEndMarkerAsync(stream, cancellationToken);
progressData.IsCompleted = true;
progress?.Report(progressData);
}
catch (Exception ex)
{
progressData.Error = ex;
progress?.Report(progressData);
throw;
}
}
/// <summary>
/// Deserialize from stream with progress reporting
/// </summary>
public async IAsyncEnumerable<T> DeserializeFromStreamAsync(
Stream stream,
SerializationOptions? options = null,
IProgress<SerializationProgress>? progress = null,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
{
options ??= new SerializationOptions();
var progressData = new SerializationProgress();
var totalBytes = stream.CanSeek ? stream.Length : 0;
await foreach (var batch in ReadBatchesAsync(stream, options, cancellationToken))
{
if (batch == null)
break; // End marker
foreach (var item in batch)
{
yield return item;
progressData.ItemsProcessed++;
}
if (stream.CanSeek)
{
progressData.BytesProcessed = stream.Position;
progressData.PercentComplete = totalBytes > 0
? (int)((stream.Position * 100) / totalBytes)
: 0;
}
progress?.Report(progressData);
}
progressData.IsCompleted = true;
progress?.Report(progressData);
}
private async Task WriteBufferAsync(
Stream stream,
List<T> buffer,
SerializationOptions options,
CancellationToken cancellationToken)
{
// Write batch header
var header = new BatchHeader
{
ItemCount = buffer.Count,
Timestamp = DateTime.UtcNow,
Checksum = CalculateChecksum(buffer)
};
await WriteBatchHeaderAsync(stream, header, cancellationToken);
// Serialize items
await _serializer.SerializeCollectionAsync(buffer, stream, options, cancellationToken);
}
private async IAsyncEnumerable<List<T>?> ReadBatchesAsync(
Stream stream,
SerializationOptions options,
[EnumeratorCancellation] CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
var header = await ReadBatchHeaderAsync(stream, cancellationToken);
if (header == null || header.ItemCount == -1)
{
yield return null; // End marker
yield break;
}
var items = new List<T>(header.ItemCount);
await foreach (var item in _serializer.DeserializeCollectionAsync<T>(
stream, options, cancellationToken).Take(header.ItemCount))
{
items.Add(item);
}
// Verify checksum if available
if (header.Checksum != 0)
{
var actualChecksum = CalculateChecksum(items);
if (actualChecksum != header.Checksum)
{
throw new InvalidDataException(
$"Checksum mismatch: expected {header.Checksum}, got {actualChecksum}");
}
}
yield return items;
}
}
private async Task WriteBatchHeaderAsync(
Stream stream,
BatchHeader header,
CancellationToken cancellationToken)
{
var buffer = _bufferPool.Rent(16);
try
{
BitConverter.TryWriteBytes(buffer.AsSpan(0, 4), header.ItemCount);
BitConverter.TryWriteBytes(buffer.AsSpan(4, 8), header.Timestamp.Ticks);
BitConverter.TryWriteBytes(buffer.AsSpan(12, 4), header.Checksum);
await stream.WriteAsync(buffer, 0, 16, cancellationToken);
}
finally
{
_bufferPool.Return(buffer);
}
}
private async Task WriteEndMarkerAsync(Stream stream, CancellationToken cancellationToken)
{
var endMarker = new BatchHeader { ItemCount = -1 };
await WriteBatchHeaderAsync(stream, endMarker, cancellationToken);
}
private async Task<BatchHeader?> ReadBatchHeaderAsync(
Stream stream,
CancellationToken cancellationToken)
{
var buffer = _bufferPool.Rent(16);
try
{
var bytesRead = await stream.ReadAsync(buffer, 0, 16, cancellationToken);
if (bytesRead < 16)
return null;
return new BatchHeader
{
ItemCount = BitConverter.ToInt32(buffer, 0),
Timestamp = new DateTime(BitConverter.ToInt64(buffer, 4)),
Checksum = BitConverter.ToInt32(buffer, 12)
};
}
finally
{
_bufferPool.Return(buffer);
}
}
private int CalculateChecksum(List<T> items)
{
// Simple checksum for validation
unchecked
{
int hash = 17;
foreach (var item in items)
{
hash = hash * 31 + (item?.GetHashCode() ?? 0);
}
return hash;
}
}
private class BatchHeader
{
public int ItemCount { get; set; }
public DateTime Timestamp { get; set; }
public int Checksum { get; set; }
}
}
/// <summary>
/// Progress information for serialization operations
/// </summary>
public class SerializationProgress
{
public long ItemsProcessed { get; set; }
public long BytesProcessed { get; set; }
public int PercentComplete { get; set; }
public bool IsCompleted { get; set; }
public Exception? Error { get; set; }
public TimeSpan Elapsed { get; set; }
public double ItemsPerSecond =>
Elapsed.TotalSeconds > 0 ? ItemsProcessed / Elapsed.TotalSeconds : 0;
public double BytesPerSecond =>
Elapsed.TotalSeconds > 0 ? BytesProcessed / Elapsed.TotalSeconds : 0;
}
/// <summary>
/// Checkpoint manager for streaming operations
/// </summary>
internal class StreamCheckpointManager
{
private readonly List<StreamCheckpoint> _checkpoints = new();
public Task CreateCheckpointAsync(
long streamPosition,
long itemsProcessed,
CancellationToken cancellationToken = default)
{
_checkpoints.Add(new StreamCheckpoint
{
StreamPosition = streamPosition,
ItemsProcessed = itemsProcessed,
Timestamp = DateTime.UtcNow
});
// Keep only √n checkpoints
var maxCheckpoints = (int)Math.Sqrt(_checkpoints.Count) + 1;
if (_checkpoints.Count > maxCheckpoints * 2)
{
// Keep evenly distributed checkpoints
var keepInterval = _checkpoints.Count / maxCheckpoints;
var newCheckpoints = new List<StreamCheckpoint>(maxCheckpoints);
for (int i = 0; i < _checkpoints.Count; i += keepInterval)
{
newCheckpoints.Add(_checkpoints[i]);
}
_checkpoints.Clear();
_checkpoints.AddRange(newCheckpoints);
}
return Task.CompletedTask;
}
public StreamCheckpoint? GetNearestCheckpoint(long targetPosition)
{
if (_checkpoints.Count == 0)
return null;
return _checkpoints
.Where(c => c.StreamPosition <= targetPosition)
.OrderByDescending(c => c.StreamPosition)
.FirstOrDefault();
}
}
internal class StreamCheckpoint
{
public long StreamPosition { get; set; }
public long ItemsProcessed { get; set; }
public DateTime Timestamp { get; set; }
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<PackageType>Template</PackageType>
<PackageId>SqrtSpace.SpaceTime.Templates</PackageId>
<Title>SpaceTime Project Templates</Title>
<Authors>David H. Friedel Jr</Authors>
<Company>MarketAlly LLC</Company>
<Copyright>Copyright © 2025 MarketAlly LLC</Copyright>
<Description>Project templates for creating SpaceTime-optimized applications</Description>
<PackageTags>dotnet-new;templates;spacetime;memory;optimization</PackageTags>
<PackageLicenseExpression>MIT</PackageLicenseExpression>
<PackageProjectUrl>https://github.com/sqrtspace/sqrtspace-dotnet</PackageProjectUrl>
<RepositoryUrl>https://www.sqrtspace.dev</RepositoryUrl>
<RepositoryType>git</RepositoryType>
<TargetFramework>net8.0</TargetFramework>
<IncludeContentInPack>true</IncludeContentInPack>
<IncludeBuildOutput>false</IncludeBuildOutput>
<ContentTargetFolders>content</ContentTargetFolders>
<NoWarn>NU5128;NU5017</NoWarn>
<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
<IsPackable>false</IsPackable>
</PropertyGroup>
<ItemGroup>
<Content Include="templates\**\*" Exclude="templates\**\bin\**;templates\**\obj\**" />
<Compile Remove="**\*" />
</ItemGroup>
</Project>

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<?xml version="1.0" encoding="utf-8"?>
<CodeSnippets xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
<CodeSnippet Format="1.0.0">
<Header>
<Title>SpaceTime LINQ External Sort</Title>
<Author>Ubiquity</Author>
<Description>Creates an external sort operation using SpaceTime LINQ</Description>
<Shortcut>stlinqsort</Shortcut>
</Header>
<Snippet>
<Declarations>
<Literal>
<ID>collection</ID>
<Default>items</Default>
</Literal>
<Literal>
<ID>keySelector</ID>
<Default>x => x.Id</Default>
</Literal>
</Declarations>
<Code Language="csharp">
<![CDATA[var sorted = $collection$.OrderByExternal($keySelector$).ToList();$end$]]>
</Code>
</Snippet>
</CodeSnippet>
<CodeSnippet Format="1.0.0">
<Header>
<Title>SpaceTime Batch Processing</Title>
<Author>Ubiquity</Author>
<Description>Process collection in √n batches</Description>
<Shortcut>stbatch</Shortcut>
</Header>
<Snippet>
<Declarations>
<Literal>
<ID>collection</ID>
<Default>items</Default>
</Literal>
</Declarations>
<Code Language="csharp">
<![CDATA[await foreach (var batch in $collection$.BatchBySqrtNAsync())
{
// Process batch
foreach (var item in batch)
{
$end$
}
}]]>
</Code>
</Snippet>
</CodeSnippet>
<CodeSnippet Format="1.0.0">
<Header>
<Title>SpaceTime Checkpoint</Title>
<Author>Ubiquity</Author>
<Description>Add checkpointing to a method</Description>
<Shortcut>stcheckpoint</Shortcut>
</Header>
<Snippet>
<Declarations>
<Literal>
<ID>methodName</ID>
<Default>ProcessData</Default>
</Literal>
</Declarations>
<Code Language="csharp">
<![CDATA[[EnableCheckpoint(Strategy = CheckpointStrategy.SqrtN)]
public async Task<Result> $methodName$Async()
{
var checkpoint = HttpContext.Features.Get<ICheckpointFeature>();
// Your processing logic
if (checkpoint?.ShouldCheckpoint() == true)
{
await checkpoint.SaveStateAsync(state);
}
$end$
}]]>
</Code>
</Snippet>
</CodeSnippet>
<CodeSnippet Format="1.0.0">
<Header>
<Title>SpaceTime Pipeline</Title>
<Author>Ubiquity</Author>
<Description>Create a SpaceTime data pipeline</Description>
<Shortcut>stpipeline</Shortcut>
</Header>
<Snippet>
<Declarations>
<Literal>
<ID>inputType</ID>
<Default>InputData</Default>
</Literal>
<Literal>
<ID>outputType</ID>
<Default>OutputData</Default>
</Literal>
</Declarations>
<Code Language="csharp">
<![CDATA[var pipeline = _pipelineFactory.CreatePipeline<$inputType$, $outputType$>("Pipeline")
.AddTransform("Transform", async (input, ct) =>
{
// Transform logic
return transformed;
})
.AddBatch("BatchProcess", async (batch, ct) =>
{
// Batch processing logic
return results;
})
.AddCheckpoint("SaveProgress")
.Build();
var result = await pipeline.ExecuteAsync(data);$end$]]>
</Code>
</Snippet>
</CodeSnippet>
<CodeSnippet Format="1.0.0">
<Header>
<Title>SpaceTime Memory Pressure Handler</Title>
<Author>Ubiquity</Author>
<Description>Monitor memory pressure</Description>
<Shortcut>stmemory</Shortcut>
</Header>
<Snippet>
<Code Language="csharp">
<![CDATA[_memoryMonitor.PressureEvents.Subscribe(e =>
{
if (e.CurrentLevel >= MemoryPressureLevel.High)
{
// Reduce memory usage
_logger.LogWarning("High memory pressure: {Level}", e.CurrentLevel);
$end$
}
});]]>
</Code>
</Snippet>
</CodeSnippet>
</CodeSnippets>

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using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using SqrtSpace.SpaceTime.Configuration;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.Linq;
using SqrtSpace.SpaceTime.MemoryManagement;
using SqrtSpace.SpaceTime.Pipeline;
using SqrtSpace.SpaceTime.Serialization;
// Build host
var host = Host.CreateDefaultBuilder(args)
.ConfigureServices((context, services) =>
{
// Add SpaceTime configuration
services.AddSpaceTimeConfiguration(context.Configuration);
// Add memory management
services.AddSpaceTimeMemoryManagement();
// Add serialization
services.AddSpaceTimeSerialization(builder =>
{
builder.UseFormat(SerializationFormat.MessagePack)
.ConfigureCompression(enable: true);
});
#if (ProcessingType == "pipeline")
// Add pipeline support
services.AddSpaceTimePipelines();
#endif
// Add application service
services.AddHostedService<DataProcessingService>();
})
.Build();
// Run application
await host.RunAsync();
/// <summary>
/// Main data processing service
/// </summary>
public class DataProcessingService : BackgroundService
{
private readonly ILogger<DataProcessingService> _logger;
private readonly ISpaceTimeConfigurationManager _configManager;
private readonly IMemoryPressureMonitor _memoryMonitor;
#if (ProcessingType == "pipeline")
private readonly IPipelineFactory _pipelineFactory;
#endif
public DataProcessingService(
ILogger<DataProcessingService> logger,
ISpaceTimeConfigurationManager configManager,
IMemoryPressureMonitor memoryMonitor
#if (ProcessingType == "pipeline")
, IPipelineFactory pipelineFactory
#endif
)
{
_logger = logger;
_configManager = configManager;
_memoryMonitor = memoryMonitor;
#if (ProcessingType == "pipeline")
_pipelineFactory = pipelineFactory;
#endif
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
_logger.LogInformation("Starting SpaceTime data processing...");
// Monitor memory pressure
_memoryMonitor.PressureEvents.Subscribe(e =>
{
_logger.LogWarning("Memory pressure changed to {Level}", e.CurrentLevel);
});
#if (ProcessingType == "batch")
await ProcessBatchDataAsync(stoppingToken);
#elif (ProcessingType == "stream")
await ProcessStreamDataAsync(stoppingToken);
#elif (ProcessingType == "pipeline")
await ProcessPipelineDataAsync(stoppingToken);
#endif
_logger.LogInformation("Data processing completed");
}
#if (ProcessingType == "batch")
private async Task ProcessBatchDataAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Processing data in batches...");
// Generate sample data
var data = GenerateData(1_000_000);
// Process in √n batches
var batchCount = 0;
await foreach (var batch in data.BatchBySqrtNAsync())
{
if (cancellationToken.IsCancellationRequested)
break;
_logger.LogInformation("Processing batch {BatchNumber} with {Count} items",
++batchCount, batch.Count);
// Sort batch using external memory if needed
var sorted = batch.OrderByExternal(x => x.Value).ToList();
// Process sorted items
foreach (var item in sorted)
{
await ProcessItemAsync(item, cancellationToken);
}
// Check memory pressure
if (_memoryMonitor.CurrentPressureLevel >= MemoryPressureLevel.High)
{
_logger.LogWarning("High memory pressure detected, triggering GC");
GC.Collect(2, GCCollectionMode.Forced);
}
}
_logger.LogInformation("Processed {BatchCount} batches", batchCount);
}
#endif
#if (ProcessingType == "stream")
private async Task ProcessStreamDataAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Processing data stream...");
var processed = 0;
var checkpointInterval = SpaceTimeCalculator.CalculateSqrtInterval(1_000_000);
await foreach (var item in GenerateDataStream(cancellationToken))
{
await ProcessItemAsync(item, cancellationToken);
processed++;
// Checkpoint progress
if (processed % checkpointInterval == 0)
{
_logger.LogInformation("Checkpoint: Processed {Count:N0} items", processed);
await SaveCheckpointAsync(processed, cancellationToken);
}
}
_logger.LogInformation("Stream processing completed: {Count:N0} items", processed);
}
#endif
#if (ProcessingType == "pipeline")
private async Task ProcessPipelineDataAsync(CancellationToken cancellationToken)
{
_logger.LogInformation("Processing data with pipeline...");
var pipeline = _pipelineFactory.CreatePipeline<DataItem, ProcessedItem>("DataPipeline")
.Configure(config =>
{
config.ExpectedItemCount = 1_000_000;
config.EnableCheckpointing = true;
})
.AddTransform("Validate", async (item, ct) =>
{
if (item.Value < 0)
throw new InvalidOperationException($"Invalid value: {item.Value}");
return item;
})
.AddBatch("Process", async (batch, ct) =>
{
_logger.LogInformation("Processing batch of {Count} items", batch.Count);
var results = new List<ProcessedItem>();
foreach (var item in batch)
{
results.Add(new ProcessedItem
{
Id = item.Id,
ProcessedValue = item.Value * 2,
ProcessedAt = DateTime.UtcNow
});
}
return results;
})
.AddCheckpoint("SaveProgress")
.Build();
var data = GenerateData(1_000_000);
var result = await pipeline.ExecuteAsync(data, cancellationToken);
_logger.LogInformation("Pipeline completed: {Count} items processed in {Duration}",
result.ProcessedCount, result.Duration);
}
#endif
private IEnumerable<DataItem> GenerateData(int count)
{
var random = new Random();
for (int i = 0; i < count; i++)
{
yield return new DataItem
{
Id = Guid.NewGuid(),
Value = random.Next(1000),
Timestamp = DateTime.UtcNow
};
}
}
private async IAsyncEnumerable<DataItem> GenerateDataStream(
[System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
{
var random = new Random();
while (!cancellationToken.IsCancellationRequested)
{
yield return new DataItem
{
Id = Guid.NewGuid(),
Value = random.Next(1000),
Timestamp = DateTime.UtcNow
};
await Task.Delay(1, cancellationToken); // Simulate data arrival
}
}
private Task ProcessItemAsync(DataItem item, CancellationToken cancellationToken)
{
// Simulate processing
return Task.CompletedTask;
}
private Task SaveCheckpointAsync(int processedCount, CancellationToken cancellationToken)
{
// Simulate checkpoint save
return File.WriteAllTextAsync(
"checkpoint.txt",
$"{processedCount},{DateTime.UtcNow:O}",
cancellationToken);
}
}
public class DataItem
{
public Guid Id { get; set; }
public int Value { get; set; }
public DateTime Timestamp { get; set; }
}
public class ProcessedItem
{
public Guid Id { get; set; }
public int ProcessedValue { get; set; }
public DateTime ProcessedAt { get; set; }
}

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>{Framework}</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting" Version="9.0.0" />
<PackageReference Include="SqrtSpace.SpaceTime.Core" Version="1.0.0" />
<PackageReference Include="SqrtSpace.SpaceTime.Linq" Version="1.0.0" />
<PackageReference Include="SqrtSpace.SpaceTime.Configuration" Version="1.0.0" />
<PackageReference Include="SqrtSpace.SpaceTime.MemoryManagement" Version="1.0.0" />
<PackageReference Include="SqrtSpace.SpaceTime.Serialization" Version="1.0.0" />
</ItemGroup>
<ItemGroup Condition="'{ProcessingType}' == 'pipeline'">
<PackageReference Include="SqrtSpace.SpaceTime.Pipeline" Version="1.0.0" />
</ItemGroup>
<ItemGroup>
<None Update="appsettings.json">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
</ItemGroup>
</Project>

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using Microsoft.AspNetCore.Mvc;
using SqrtSpace.SpaceTime.AspNetCore;
using SqrtSpace.SpaceTime.Core;
using SqrtSpace.SpaceTime.Linq;
namespace SpaceTimeWebApi.Controllers;
[ApiController]
[Route("api/[controller]")]
public class DataController : ControllerBase
{
private readonly ILogger<DataController> _logger;
public DataController(ILogger<DataController> logger)
{
_logger = logger;
}
/// <summary>
/// Processes large dataset with SpaceTime optimizations
/// </summary>
[HttpPost("process")]
[EnableCheckpoint(Strategy = CheckpointStrategy.SqrtN)]
public async Task<IActionResult> ProcessLargeDataset([FromBody] ProcessRequest request)
{
var checkpoint = HttpContext.Features.Get<ICheckpointFeature>();
var results = new List<ProcessedItem>();
try
{
// Process in √n batches
await foreach (var batch in GetDataItems(request.DataSource).BatchBySqrtNAsync())
{
foreach (var item in batch)
{
var processed = await ProcessItem(item);
results.Add(processed);
}
// Checkpoint progress
if (checkpoint?.ShouldCheckpoint() == true)
{
await checkpoint.SaveStateAsync(new
{
ProcessedCount = results.Count,
LastProcessedId = results.LastOrDefault()?.Id
});
}
}
return Ok(new ProcessResponse
{
TotalProcessed = results.Count,
Success = true
});
}
catch (Exception ex)
{
_logger.LogError(ex, "Error processing dataset");
return StatusCode(500, new { error = "Processing failed" });
}
}
/// <summary>
/// Streams large dataset with √n chunking
/// </summary>
[HttpGet("stream")]
[SpaceTimeStreaming(ChunkStrategy = ChunkStrategy.SqrtN)]
public async IAsyncEnumerable<DataItem> StreamLargeDataset([FromQuery] int? limit = null)
{
var count = 0;
await foreach (var item in GetDataItems("default"))
{
if (limit.HasValue && count >= limit.Value)
break;
yield return item;
count++;
}
}
/// <summary>
/// Sorts large dataset using external memory
/// </summary>
[HttpPost("sort")]
public async Task<IActionResult> SortLargeDataset([FromBody] SortRequest request)
{
try
{
var items = await GetDataItems(request.DataSource).ToListAsync();
// Use external sorting for large datasets
var sorted = items.OrderByExternal(x => x.Value)
.ThenByExternal(x => x.Timestamp)
.ToList();
return Ok(new
{
Count = sorted.Count,
First = sorted.FirstOrDefault(),
Last = sorted.LastOrDefault()
});
}
catch (Exception ex)
{
_logger.LogError(ex, "Error sorting dataset");
return StatusCode(500, new { error = "Sorting failed" });
}
}
private async IAsyncEnumerable<DataItem> GetDataItems(string source)
{
// Simulate data source
var random = new Random();
for (int i = 0; i < 1_000_000; i++)
{
yield return new DataItem
{
Id = Guid.NewGuid().ToString(),
Value = random.Next(1000),
Timestamp = DateTime.UtcNow.AddMinutes(-random.Next(10000)),
Data = $"Item {i} from {source}"
};
if (i % 1000 == 0)
await Task.Yield();
}
}
private Task<ProcessedItem> ProcessItem(DataItem item)
{
// Simulate processing
return Task.FromResult(new ProcessedItem
{
Id = item.Id,
ProcessedValue = item.Value * 2,
ProcessedAt = DateTime.UtcNow
});
}
}
public class ProcessRequest
{
public string DataSource { get; set; } = "default";
public Dictionary<string, object>? Parameters { get; set; }
}
public class ProcessResponse
{
public int TotalProcessed { get; set; }
public bool Success { get; set; }
}
public class SortRequest
{
public string DataSource { get; set; } = "default";
public string SortBy { get; set; } = "value";
}
public class DataItem
{
public string Id { get; set; } = "";
public int Value { get; set; }
public DateTime Timestamp { get; set; }
public string Data { get; set; } = "";
}
public class ProcessedItem
{
public string Id { get; set; } = "";
public int ProcessedValue { get; set; }
public DateTime ProcessedAt { get; set; }
}

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