Performance optimisations

.gitignore

@@ -314,3 +314,5 @@ version.txt
 /docs/.docusaurus/
 /docs/build/
 /docs/.yarn/
+
+BenchmarkDotNet.Artifacts/

.run/KurrentDB Bookings.run.xml

@@ -0,0 +1,18 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="KurrentDB Bookings" type="LaunchSettings" factoryName=".NET Launch Settings Profile">
+    <option name="LAUNCH_PROFILE_PROJECT_FILE_PATH" value="$PROJECT_DIR$/samples/kurrentdb/Bookings/Bookings.csproj" />
+    <option name="LAUNCH_PROFILE_TFM" value="net10.0" />
+    <option name="LAUNCH_PROFILE_NAME" value="Samples.KurrentDB.Bookings" />
+    <option name="USE_MONO" value="0" />
+    <option name="RUNTIME_ARGUMENTS" value="" />
+    <option name="GENERATE_APPLICATIONHOST_CONFIG" value="1" />
+    <option name="SHOW_IIS_EXPRESS_OUTPUT" value="0" />
+    <option name="SEND_DEBUG_REQUEST" value="1" />
+    <option name="ADDITIONAL_IIS_EXPRESS_ARGUMENTS" value="" />
+    <option name="AUTO_ATTACH_CHILDREN" value="0" />
+    <option name="MIXED_MODE_DEBUG" value="0" />
+    <method v="2">
+      <option name="Build" />
+    </method>
+  </configuration>
+</component>

Eventuous.slnx

@@ -140,10 +140,10 @@
         <Project Path="src/SqlServer/test/Eventuous.Tests.SqlServer/Eventuous.Tests.SqlServer.csproj" />
     </Folder>
     <Folder Name="/Samples/" />
-    <Folder Name="/Samples/Esdb/">
-        <Project Path="samples/esdb/Bookings.Domain/Bookings.Domain.csproj" />
-        <Project Path="samples/esdb/Bookings.Payments/Bookings.Payments.csproj" />
-        <Project Path="samples/esdb/Bookings/Bookings.csproj" />
+    <Folder Name="/Samples/KurrentDB/">
+        <Project Path="samples/kurrentdb/Bookings.Domain/Bookings.Domain.csproj" />
+        <Project Path="samples/kurrentdb/Bookings.Payments/Bookings.Payments.csproj" />
+        <Project Path="samples/kurrentdb/Bookings/Bookings.csproj" />
     </Folder>
     <Folder Name="/Samples/Postgres/">
         <Project Path="samples/postgres/Bookings.Domain/Bookings.Domain.csproj" />

samples/esdb/Bookings/Bookings.csproj → samples/kurrentdb/Bookings/Bookings.csproj

@@ -5,6 +5,7 @@
         <Platforms>AnyCPU</Platforms>
         <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
         <CompilerGeneratedFilesOutputPath>obj/Generated</CompilerGeneratedFilesOutputPath>
+        <OutputType>exe</OutputType>
     </PropertyGroup>
     <ItemGroup>
         <PackageReference Include="FluentValidation"/>

samples/esdb/docker-compose.yml → samples/kurrentdb/docker-compose.yml

@@ -1,21 +1,21 @@
 services:
 
-  esdb:
-    container_name: esdemo-esdb
-    image: eventstore/eventstore:23.10.2-alpha-arm64v8
-    #    image: eventstore/eventstore:latest #23.10.2-buster-slim
-    ports:
-      - '2113:2113'
-      - '1113:1113'
-    environment:
-      EVENTSTORE_INSECURE: 'true'
-      EVENTSTORE_CLUSTER_SIZE: 1
-      EVENTSTORE_EXT_TCP_PORT: 1113
-      EVENTSTORE_HTTP_PORT: 2113
-      EVENTSTORE_ENABLE_EXTERNAL_TCP: 'true'
-      EVENTSTORE_RUN_PROJECTIONS: all
-      EVENTSTORE_START_STANDARD_PROJECTIONS: "true"
-      EVENTSTORE_ENABLE_ATOM_PUB_OVER_HTTP: "true"
+#  esdb:
+#    container_name: esdemo-esdb
+#    image: eventstore/eventstore:23.10.2-alpha-arm64v8
+#    #    image: eventstore/eventstore:latest #23.10.2-buster-slim
+#    ports:
+#      - '2113:2113'
+#      - '1113:1113'
+#    environment:
+#      EVENTSTORE_INSECURE: 'true'
+#      EVENTSTORE_CLUSTER_SIZE: 1
+#      EVENTSTORE_EXT_TCP_PORT: 1113
+#      EVENTSTORE_HTTP_PORT: 2113
+#      EVENTSTORE_ENABLE_EXTERNAL_TCP: 'true'
+#      EVENTSTORE_RUN_PROJECTIONS: all
+#      EVENTSTORE_START_STANDARD_PROJECTIONS: "true"
+#      EVENTSTORE_ENABLE_ATOM_PUB_OVER_HTTP: "true"
 
   mongo:
     container_name: esdemo-mongo

samples/postgres/Bookings.Domain/Bookings.Domain.csproj

@@ -10,7 +10,7 @@
       <ProjectReference Include="$(CoreRoot)\Eventuous.Shared\Eventuous.Shared.csproj" />
     </ItemGroup>
     <ItemGroup>
-        <Compile Include="..\..\esdb\Bookings.Domain\*.cs" />
-        <Compile Include="..\..\esdb\Bookings.Domain\Bookings\*.cs" LinkBase="Bookings" />
+        <Compile Include="..\..\kurrentdb\Bookings.Domain\*.cs" />
+        <Compile Include="..\..\kurrentdb\Bookings.Domain\Bookings\*.cs" LinkBase="Bookings" />
     </ItemGroup>
 </Project>

samples/postgres/Bookings.Payments/Bookings.Payments.csproj

@@ -29,8 +29,8 @@
         <Compile Include="..\Bookings\Infrastructure\Telemetry.cs">
             <Link>Infrastructure\Telemetry.cs</Link>
         </Compile>
-        <Compile Include="..\..\esdb\Bookings.Payments\Domain\*.cs" LinkBase="Domain"/>
-        <Compile Include="..\..\esdb\Bookings.Payments\Application\*.cs" LinkBase="Application"/>
+        <Compile Include="..\..\kurrentdb\Bookings.Payments\Domain\*.cs" LinkBase="Domain"/>
+        <Compile Include="..\..\kurrentdb\Bookings.Payments\Application\*.cs" LinkBase="Application"/>
     </ItemGroup>
     <ItemGroup>
         <ProjectReference Include="$(SrcRoot)\Diagnostics\src\Eventuous.Diagnostics.OpenTelemetry\Eventuous.Diagnostics.OpenTelemetry.csproj"/>

samples/postgres/Bookings/Bookings.csproj

@@ -30,6 +30,6 @@
         <ProjectReference Include="$(SrcRoot)\Postgres\src\Eventuous.Postgresql\Eventuous.Postgresql.csproj"/>
         <ProjectReference Include="$(SrcRoot)\RabbitMq\src\Eventuous.RabbitMq\Eventuous.RabbitMq.csproj"/>
         <ProjectReference Include="$(SrcRoot)\Core\gen\Eventuous.Subscriptions.Generators\Eventuous.Subscriptions.Generators.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
-        <ProjectReference Include="..\Bookings.Domain\Bookings.Domain.csproj"/>
+        <ProjectReference Include="..\Bookings.Domain\Bookings.Domain.csproj" />
     </ItemGroup>
 </Project>

src/Benchmarks/Benchmarks/AllocationHotspotsBenchmarks.cs

@@ -0,0 +1,131 @@
+using BenchmarkDotNet.Attributes;
+using System.Text;
+
+namespace Benchmarks;
+
+/// <summary>
+/// Benchmarks for common allocation hotspots identified in the analysis.
+/// Focuses on dictionary allocations, string formatting, and LINQ usage.
+/// Reference: PERFORMANCE_ANALYSIS.md sections 1, 13
+/// </summary>
+[MemoryDiagnoser]
+[SimpleJob(warmupCount: 3, iterationCount: 5)]
+public class AllocationHotspotsBenchmarks {
+    string _subscriptionId = null!;
+    string _streamName = null!;
+    string _messageType = null!;
+
+    [GlobalSetup]
+    public void Setup() {
+        _subscriptionId = "test-subscription-id";
+        _streamName = "test-stream-name";
+        _messageType = "TestEventType";
+    }
+
+    [Benchmark(Baseline = true, Description = "Dictionary for logging scope (current)")]
+    public Dictionary<string, object> CreateLoggingScopeDictionary() {
+        return new() {
+            { "SubscriptionId", _subscriptionId },
+            { "Stream", _streamName },
+            { "MessageType", _messageType }
+        };
+    }
+
+    [Benchmark(Description = "Array of KeyValuePairs (alternative)")]
+    public KeyValuePair<string, object>[] CreateLoggingScopeArray() {
+        return [
+            new("SubscriptionId", _subscriptionId),
+            new("Stream", _streamName),
+            new("MessageType", _messageType)
+        ];
+    }
+
+    [Benchmark(Description = "Activity name - string interpolation")]
+    public string ActivityNameInterpolation() {
+        return $"Subscription.{_subscriptionId}/{_messageType}";
+    }
+
+    [Benchmark(Description = "Activity name - string concat")]
+    public string ActivityNameConcat() {
+        return string.Concat("Subscription.", _subscriptionId, "/", _messageType);
+    }
+
+    [Benchmark(Description = "Activity name - StringBuilder")]
+    public string ActivityNameStringBuilder() {
+        var sb = new StringBuilder(64);
+        sb.Append("Subscription.");
+        sb.Append(_subscriptionId);
+        sb.Append('/');
+        sb.Append(_messageType);
+        return sb.ToString();
+    }
+
+    [Benchmark(Description = "LINQ Any() check on small list")]
+    public bool LinqAnyOnSmallList() {
+        var list = new List<string> { "item1", "item2", "item3" };
+        return list.Any(x => x == "item2");
+    }
+
+    [Benchmark(Description = "Manual iteration on small list")]
+    public bool ManualIterationOnSmallList() {
+        var list = new List<string> { "item1", "item2", "item3" };
+        foreach (var item in list) {
+            if (item == "item2") return true;
+        }
+        return false;
+    }
+
+    [Benchmark(Description = "LINQ Where().Any() pattern")]
+    public bool LinqWhereAny() {
+        var items = Enumerable.Range(0, 20).Select(i => new TestItem { Id = i, Active = i % 2 == 0 });
+        return items.Any(x => x.Active);
+    }
+
+    [Benchmark(Description = "LINQ Any() with predicate")]
+    public bool LinqAnyWithPredicate() {
+        var items = Enumerable.Range(0, 20).Select(i => new TestItem { Id = i, Active = i % 2 == 0 });
+        return items.Any(x => x.Active);
+    }
+
+    [Benchmark(Description = "Manual enumeration check")]
+    public bool ManualEnumerationCheck() {
+        var items = Enumerable.Range(0, 20).Select(i => new TestItem { Id = i, Active = i % 2 == 0 });
+        foreach (var item in items) {
+            if (item.Active) return true;
+        }
+        return false;
+    }
+
+    [Benchmark(Description = "CancellationTokenSource creation")]
+    public CancellationTokenSource CreateCancellationTokenSource() {
+        var cts = new CancellationTokenSource();
+        cts.Dispose();
+        return cts;
+    }
+
+    [Benchmark(Description = "Linked CancellationTokenSource")]
+    public CancellationTokenSource CreateLinkedCancellationTokenSource() {
+        var cts1 = new CancellationTokenSource();
+        var cts2 = new CancellationTokenSource();
+        var linked = CancellationTokenSource.CreateLinkedTokenSource(cts1.Token, cts2.Token);
+        linked.Dispose();
+        cts2.Dispose();
+        cts1.Dispose();
+        return linked;
+    }
+
+    [Benchmark(Description = "Guid.ToString()")]
+    public string GuidToString() {
+        return Guid.NewGuid().ToString();
+    }
+
+    [Benchmark(Description = "DateTime.UtcNow allocation")]
+    public DateTime GetUtcNow() {
+        return DateTime.UtcNow;
+    }
+
+    class TestItem {
+        public int Id { get; set; }
+        public bool Active { get; set; }
+    }
+}

src/Benchmarks/Benchmarks/Benchmarks.csproj

@@ -6,12 +6,16 @@
     <ItemGroup>
         <ProjectReference Include="$(CoreRoot)\Eventuous.Application\Eventuous.Application.csproj"/>
         <ProjectReference Include="$(CoreRoot)\Eventuous.Subscriptions\Eventuous.Subscriptions.csproj"/>
+        <ProjectReference Include="$(SrcRoot)\Core\gen\Eventuous.Subscriptions.Generators\Eventuous.Subscriptions.Generators.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+        <ProjectReference Include="$(SrcRoot)\Core\gen\Eventuous.Shared.Generators\Eventuous.Shared.Generators.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
     </ItemGroup>
     <ItemGroup>
         <PackageReference Include="BenchmarkDotNet"/>
     </ItemGroup>
     <ItemGroup>
       <Compile Remove="GapDetectionBenchmarks.cs" />
       <Compile Remove="TypeMapBenchmark.cs" />
+      <Compile Remove="FilterPipelineBenchmarks.cs" />
+      <Compile Remove="CheckpointBenchmarks.cs" />
     </ItemGroup>
 </Project>

src/Benchmarks/Benchmarks/ChannelBatchingBenchmarks.cs

@@ -0,0 +1,83 @@
+using BenchmarkDotNet.Attributes;
+using System.Buffers;
+
+namespace Benchmarks;
+
+/// <summary>
+/// Benchmarks for channel batching ToArray optimization.
+/// Tests different approaches to returning batched results.
+/// Reference: PERFORMANCE_ANALYSIS.md - Issue #10: Channel Batching List.ToArray()
+/// </summary>
+[MemoryDiagnoser]
+[SimpleJob(warmupCount: 3, iterationCount: 5)]
+public class ChannelBatchingBenchmarks {
+    private List<int> _buffer = null!;
+
+    [Params(10, 50, 100)]
+    public int BatchSize { get; set; }
+
+    [GlobalSetup]
+    public void Setup() {
+        _buffer = new List<int>(BatchSize);
+        for (int i = 0; i < BatchSize; i++) {
+            _buffer.Add(i);
+        }
+    }
+
+    [Benchmark(Baseline = true, Description = "Current: List.ToArray()")]
+    public int[] CurrentApproach_ToArray() {
+        return _buffer.ToArray();
+    }
+
+    [Benchmark(Description = "Alternative 1: CollectionsMarshal.AsSpan()")]
+    public ReadOnlySpan<int> Alternative1_CollectionsMarshalAsSpan() {
+        return System.Runtime.InteropServices.CollectionsMarshal.AsSpan(_buffer);
+    }
+
+    [Benchmark(Description = "Alternative 2: ArrayPool rent/copy")]
+    public int[] Alternative2_ArrayPool() {
+        var array = ArrayPool<int>.Shared.Rent(_buffer.Count);
+        _buffer.CopyTo(array);
+        return array; // Note: caller must return to pool
+    }
+
+    [Benchmark(Description = "Alternative 3: Pre-allocated array with CopyTo")]
+    public int[] Alternative3_PreAllocatedArray() {
+        var array = new int[_buffer.Count];
+        _buffer.CopyTo(array);
+        return array;
+    }
+
+    [Benchmark(Description = "Alternative 4: Direct List (no copy)")]
+    public List<int> Alternative4_DirectList() {
+        return _buffer; // Returns list directly - consumer must handle as read-only
+    }
+
+    [Benchmark(Description = "Alternative 5: IReadOnlyList wrapper")]
+    public IReadOnlyList<int> Alternative5_ReadOnlyWrapper() {
+        return _buffer.AsReadOnly();
+    }
+
+    // Cleanup benchmark (shows ArrayPool return overhead)
+    private int[]? _rentedArray;
+
+    [IterationSetup(Target = nameof(WithArrayPoolReturnOverhead))]
+    public void SetupRentedArray() {
+        _rentedArray = ArrayPool<int>.Shared.Rent(_buffer.Count);
+        _buffer.CopyTo(_rentedArray);
+    }
+
+    [Benchmark(Description = "Alternative 2b: ArrayPool with return overhead")]
+    public int[] WithArrayPoolReturnOverhead() {
+        var result = _rentedArray;
+        return result!;
+    }
+
+    [IterationCleanup(Target = nameof(WithArrayPoolReturnOverhead))]
+    public void CleanupRentedArray() {
+        if (_rentedArray != null) {
+            ArrayPool<int>.Shared.Return(_rentedArray);
+            _rentedArray = null;
+        }
+    }
+}