Merge pull request #249 from servicetitan/upstream/OptimizeTracking

Optimize Tracking: convert ChangedValue & TrackingStackFrame to readonly structs

Author: alex-kulakov

Extensions/Xtensive.Orm.Tracking.Tests/TrackingStackFrameTests.cs

@@ -11,7 +11,7 @@ public class TrackingStackFrameTests : TrackingTestBase
     [Test]
     public void SafelyInsertTheSameItemTwiceTest()
     {
-      var frame = new TrackingStackFrame();
+      var frame = new TrackingStackFrame(false);
       var key = Key.Create(Domain, typeof(MyEntity), 1);
       var item = CreateTrackingItem(key, TrackingItemState.Created);
       frame.Register(item);
@@ -21,8 +21,8 @@ public void SafelyInsertTheSameItemTwiceTest()
     [Test]
     public void MergeTwoEmptyFramesTest()
     {
-      var target = new TrackingStackFrame();
-      var source = new TrackingStackFrame();
+      var target = new TrackingStackFrame(false);
+      var source = new TrackingStackFrame(false);
       target.MergeWith(source);
 
       Assert.AreEqual(0, target.Count);
@@ -32,9 +32,9 @@ public void MergeTwoEmptyFramesTest()
     public void MergeEmptyFrameWithNonEmptyFrameTest()
     {
       var key = Key.Create(Domain, typeof(MyEntity), 1);
-      var target = new TrackingStackFrame();
+      var target = new TrackingStackFrame(false);
 
-      var source = new TrackingStackFrame();
+      var source = new TrackingStackFrame(false);
       source.Register(CreateTrackingItem(key, TrackingItemState.Created));
 
       target.MergeWith(source);
@@ -46,11 +46,11 @@ public void MergeEmptyFrameWithNonEmptyFrameTest()
     public void MergeNonEmptyFrameWithEmptyFrameTest()
     {
       var key = Key.Create(Domain, typeof(MyEntity), 1);
-      var target = new TrackingStackFrame();
+      var target = new TrackingStackFrame(false);
       target.Register(CreateTrackingItem(key, TrackingItemState.Created));
       var count = target.Count;
 
-      var source = new TrackingStackFrame();
+      var source = new TrackingStackFrame(false);
 
       target.MergeWith(source);
 
@@ -61,11 +61,11 @@ public void MergeNonEmptyFrameWithEmptyFrameTest()
     public void MergeFramesWithTheSameItemsTest()
     {
       var key = Key.Create(Domain, typeof(MyEntity), 1);
-      var target = new TrackingStackFrame();
+      var target = new TrackingStackFrame(false);
       target.Register(CreateTrackingItem(key, TrackingItemState.Created));
       var count = target.Count;
 
-      var source = new TrackingStackFrame();
+      var source = new TrackingStackFrame(false);
       source.Register(CreateTrackingItem(key, TrackingItemState.Changed));
 
       target.MergeWith(source);
@@ -79,10 +79,10 @@ public void MergeFramesWithDifferentItemsTest()
     {
       var key1 = Key.Create(Domain, typeof(MyEntity), 1);
       var key2 = Key.Create(Domain, typeof(MyEntity), 2);
-      var target = new TrackingStackFrame();
+      var target = new TrackingStackFrame(false);
       target.Register(CreateTrackingItem(key1, TrackingItemState.Created));
 
-      var source = new TrackingStackFrame();
+      var source = new TrackingStackFrame(false);
       source.Register(CreateTrackingItem(key2, TrackingItemState.Changed));
       var count = target.Count + source.Count;
 

Extensions/Xtensive.Orm.Tracking/ChangedValue.cs

@@ -1,26 +1,30 @@
-using Xtensive.Orm.Model;
+// Copyright (C) 2012-2022 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
+
+using Xtensive.Orm.Model;
 
 namespace Xtensive.Orm.Tracking
 {
   /// <summary>
   /// Represents a pair of original and changed values for a persistent field
   /// </summary>
-  public sealed class ChangedValue
+  public readonly struct ChangedValue
   {
     /// <summary>
     /// Gets the field.
     /// </summary>
-    public FieldInfo Field { get; private set; }
+    public FieldInfo Field { get; }
 
     /// <summary>
     /// Gets the original value.
     /// </summary>
-    public object OriginalValue { get; private set; }
+    public object OriginalValue { get; }
 
     /// <summary>
     /// Gets the new value.
     /// </summary>
-    public object NewValue { get; private set; }
+    public object NewValue { get; }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="ChangedValue"/> class.

Extensions/Xtensive.Orm.Tracking/Interfaces/ITrackingItem.cs

@@ -32,6 +32,6 @@ public interface ITrackingItem
     /// <summary>
     /// Gets list of detected changes of field values.
     /// </summary>
-    IList<ChangedValue> ChangedValues { get; }
+    IReadOnlyList<ChangedValue> ChangedValues { get; }
   }
 }

Extensions/Xtensive.Orm.Tracking/Internals/SessionTrackingMonitor.cs

@@ -1,4 +1,4 @@
-// Copyright (C) 2019-2020 Xtensive LLC.
+// Copyright (C) 2019-2022 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 
@@ -15,19 +15,20 @@ internal sealed class SessionTrackingMonitor : TrackingMonitor, ISessionTracking
   {
     private readonly Session session;
     private readonly DirectSessionAccessor accessor;
-    private readonly Stack<TrackingStackFrame> stack;
+    private readonly Stack<TrackingStackFrame> stack = new(2);
 
     private void Subscribe()
     {
-      session.Events.Persisting += OnPersisting;
-      session.Events.TransactionOpened += OnOpenTransaction;
-      session.Events.TransactionCommitted += OnCommitTransaction;
-      session.Events.TransactionRollbacked += OnRollbackTransaction;
+      var events = session.Events;
+      events.Persisting += OnPersisting;
+      events.TransactionOpened += OnOpenTransaction;
+      events.TransactionCommitted += OnCommitTransaction;
+      events.TransactionRollbacked += OnRollbackTransaction;
     }
 
     private void OnOpenTransaction(object sender, TransactionEventArgs e)
     {
-      stack.Push(new TrackingStackFrame());
+      stack.Push(new TrackingStackFrame(false));
     }
 
     private void OnCommitTransaction(object sender, TransactionEventArgs e)
@@ -76,16 +77,10 @@ private void OnPersisting(object sender, EventArgs e)
     [ServiceConstructor]
     public SessionTrackingMonitor(Session session, DirectSessionAccessor accessor)
     {
-      if (session==null)
-        throw new ArgumentNullException("session");
-      if (accessor==null)
-        throw new ArgumentNullException("accessor");
+      this.session = session ?? throw new ArgumentNullException(nameof(session));
+      this.accessor = accessor ?? throw new ArgumentNullException(nameof(accessor));
 
-      this.session = session;
-      this.accessor = accessor;
-
-      stack = new Stack<TrackingStackFrame>();
-      stack.Push(new TrackingStackFrame());
+      stack.Push(new TrackingStackFrame(false));
 
       Subscribe();
     }

Extensions/Xtensive.Orm.Tracking/Internals/TrackingItem.cs

@@ -1,6 +1,6 @@
-// Copyright (C) 2012 Xtensive LLC.
-// All rights reserved.
-// For conditions of distribution and use, see license.
+// Copyright (C) 2012-2022 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
 // Created by: Dmitri Maximov
 // Created:    2012.05.16
 
@@ -16,23 +16,15 @@ namespace Xtensive.Orm.Tracking
   [DebuggerDisplay("{Key}")]
   internal sealed class TrackingItem : ITrackingItem
   {
-    private IList<ChangedValue> cachedChangedValues;
+    private IReadOnlyList<ChangedValue> cachedChangedValues;
 
-    public Key Key { get; private set; }
+    public Key Key { get; }
 
     public DifferentialTuple RawData { get; private set; }
 
     public TrackingItemState State { get; private set; }
 
-    public IList<ChangedValue> ChangedValues
-    {
-      get
-      {
-        if (cachedChangedValues==null)
-          cachedChangedValues = CalculateChangedValues().ToList().AsReadOnly();
-        return cachedChangedValues;
-      }
-    }
+    public IReadOnlyList<ChangedValue> ChangedValues => cachedChangedValues ??= CalculateChangedValues();
 
     public void MergeWith(TrackingItem source)
     {
@@ -55,29 +47,33 @@ public void MergeWith(TrackingItem source)
       State = source.State;
     }
 
-    private IEnumerable<ChangedValue> CalculateChangedValues()
+    private IReadOnlyList<ChangedValue> CalculateChangedValues()
     {
       var originalValues = RawData.Origin;
       var changedValues = RawData.Difference;
 
-      if (State==TrackingItemState.Created) {
+      if (State == TrackingItemState.Created) {
         originalValues = null;
         changedValues = RawData.Origin;
       }
 
-      foreach (var field in Key.TypeInfo.Fields.Where(f => f.Column!=null)) {
+      var changedValuesList = new List<ChangedValue>(Key.TypeInfo.Fields.Count);
+
+      foreach (var field in Key.TypeInfo.Fields.Where(f => f.Column != null)) {
         object origValue = null, changedValue = null;
         int fieldIndex = field.MappingInfo.Offset;
         TupleFieldState fieldState;
-        if (originalValues!=null)
+        if (originalValues != null)
           origValue = originalValues.GetValue(fieldIndex, out fieldState);
-        if (changedValues!=null) {
+        if (changedValues != null) {
           changedValue = changedValues.GetValue(fieldIndex, out fieldState);
           if (!fieldState.IsAvailable())
             continue;
         }
-        yield return new ChangedValue(field, origValue, changedValue);
+        changedValuesList.Add(new ChangedValue(field, origValue, changedValue));
       }
+
+      return changedValuesList.AsReadOnly();
     }
 
     private void MergeWith(Tuple difference)

Extensions/Xtensive.Orm.Tracking/Internals/TrackingStackFrame.cs

@@ -1,64 +1,58 @@
-// Copyright (C) 2012 Xtensive LLC.
-// All rights reserved.
-// For conditions of distribution and use, see license.
+// Copyright (C) 2012-2022 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
 // Created by: Dmitri Maximov
 // Created:    2012.05.16
 
-using System;
 using System.Collections;
 using System.Collections.Generic;
+using Xtensive.Core;
 
 namespace Xtensive.Orm.Tracking
 {
-  internal sealed class TrackingStackFrame : IEnumerable<TrackingItem>
+  internal readonly struct TrackingStackFrame : IEnumerable<TrackingItem>
   {
-    private readonly Dictionary<Key, TrackingItem> items = new Dictionary<Key, TrackingItem>();
+    private readonly Dictionary<Key, TrackingItem> items;
 
-    public int Count { get { return items.Count; } }
+    public int Count => items.Count;
 
     public void Register(TrackingItem item)
     {
-      if (item==null)
-        throw new ArgumentNullException("item");
-
-      TrackingItem existing;
-      if (items.TryGetValue(item.Key, out existing)) {
-        if (item==existing)
-          return;
+      ArgumentValidator.EnsureArgumentNotNull(item, "item");
 
+      var key = item.Key;
+      if (!items.TryGetValue(key, out var existing)) {
+        items.Add(key, item);
+      }
+      else if (item != existing) {
         existing.MergeWith(item);
-        return;
       }
-      items.Add(item.Key, item);
     }
 
-    public void Clear()
-    {
-      items.Clear();
-    }
+    public void Clear() => items.Clear();
 
     public void MergeWith(TrackingStackFrame source)
     {
-      if (source==null)
-        throw new ArgumentNullException("source");
-
       foreach (var sourceItem in source) {
-        TrackingItem target;
-        if (items.TryGetValue(sourceItem.Key, out target))
-          target.MergeWith(sourceItem);
-        else
-          items.Add(sourceItem.Key, sourceItem);
+        var key = sourceItem.Key;
+        if (items.TryGetValue(key, out var existing)) {
+          existing.MergeWith(sourceItem);
+        }
+        else {
+          items.Add(key, sourceItem);
+        }
       }
     }
 
-    public IEnumerator<TrackingItem> GetEnumerator()
-    {
-      return items.Values.GetEnumerator();
-    }
+    public IEnumerator<TrackingItem> GetEnumerator() => items.Values.GetEnumerator();
+
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 
-    IEnumerator IEnumerable.GetEnumerator()
+    // parameterless ctor not allowed in C#9
+    //TODO: remove it after moving to C#10
+    public TrackingStackFrame(bool _)
     {
-      return GetEnumerator();
+      items = new();
     }
   }
-}
+}

Orm/Xtensive.Orm.Tests.Core/Xtensive.Orm.Tests.Core.csproj

@@ -21,5 +21,5 @@
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.2.0" />
   </ItemGroup>
- 
+
 </Project>

Orm/Xtensive.Orm.Tests.Framework/Xtensive.Orm.Tests.Framework.csproj

@@ -2,7 +2,6 @@
   <PropertyGroup>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <IsPackable>false</IsPackable>
-    <DefineConstants>TRACE</DefineConstants>
     <Configurations>Debug;Release;Debug-NET5;Release-NET5;Debug-NET6;Release-NET6;</Configurations>
   </PropertyGroup>
   <PropertyGroup>

Orm/Xtensive.Orm/Orm/Services/DirectSessionAccessor.cs

@@ -57,7 +57,7 @@ public IDisposable ChangeSessionHandler(SessionHandler newHandler)
     /// An object implementing <see cref="IDisposable"/> which
     /// disposal will restore previous state of
     /// <see cref="Session.Transaction"/> property;
-    /// <see langword="null" />, if <see cref="Session.Transaction"/> 
+    /// <see langword="null" />, if <see cref="Session.Transaction"/>
     /// is already <see langword="null" />.
     /// </returns>
     public IDisposable NullifySessionTransaction()

Orm/Xtensive.Orm/Properties/Visibility.cs

@@ -6,19 +6,19 @@
 
 using System.Runtime.CompilerServices;
 
-[assembly: InternalsVisibleTo("Xtensive.Orm.Tests.Framework, PublicKey=" + 
+[assembly: InternalsVisibleTo("Xtensive.Orm.Tests.Framework, PublicKey=" +
 "0024000004800000940000000602000000240000525341310004000001000100fbdd689d62e9c6" +
 "7bb6356267f95e0b58d478cf56393c4f060fbaff42a9686272e37009ab71bfa2e41046e952f389" +
 "f37c6a033d1a2a5354fc97226fc469128e49e6a479ac5d1dd69d7da5607d0dc4ede0765d477745" +
 "1034dc3a15f1532d010db3e633e62fc5e67a3ed175457acb9dc6c9d39ccc8ecfdaae62df34d488" +
 "c45009b2")]
-[assembly: InternalsVisibleTo("Xtensive.Orm.Tests.Core, PublicKey=" + 
+[assembly: InternalsVisibleTo("Xtensive.Orm.Tests.Core, PublicKey=" +
 "0024000004800000940000000602000000240000525341310004000001000100fbdd689d62e9c6" +
 "7bb6356267f95e0b58d478cf56393c4f060fbaff42a9686272e37009ab71bfa2e41046e952f389" +
 "f37c6a033d1a2a5354fc97226fc469128e49e6a479ac5d1dd69d7da5607d0dc4ede0765d477745" +
 "1034dc3a15f1532d010db3e633e62fc5e67a3ed175457acb9dc6c9d39ccc8ecfdaae62df34d488" +
 "c45009b2")]
-[assembly: InternalsVisibleTo("Xtensive.Orm.Tests, PublicKey=" + 
+[assembly: InternalsVisibleTo("Xtensive.Orm.Tests, PublicKey=" +
 "0024000004800000940000000602000000240000525341310004000001000100fbdd689d62e9c6" +
 "7bb6356267f95e0b58d478cf56393c4f060fbaff42a9686272e37009ab71bfa2e41046e952f389" +
 "f37c6a033d1a2a5354fc97226fc469128e49e6a479ac5d1dd69d7da5607d0dc4ede0765d477745" +
@@ -29,4 +29,4 @@
 "7bb6356267f95e0b58d478cf56393c4f060fbaff42a9686272e37009ab71bfa2e41046e952f389" +
 "f37c6a033d1a2a5354fc97226fc469128e49e6a479ac5d1dd69d7da5607d0dc4ede0765d477745" +
 "1034dc3a15f1532d010db3e633e62fc5e67a3ed175457acb9dc6c9d39ccc8ecfdaae62df34d488" +
-"c45009b2")]
+"c45009b2")]