From 10c27358265c1785fa064d86d522db38e390c527 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Sat, 20 Nov 2021 00:55:57 -0800
Subject: [PATCH 01/12] Split type-unsafe InternalQueryCache into 4 statically
 typed caches (#57)

* Split type-unsafe InternalQueryCache into three statically typed caches

* Remove unused     indexSeekCachingRegion

* Make BuildEntitySetTypeState static delegate

* Rename EntitySetTask.CacheKey -> ItemsQueryCacheKey

* Make CacheKey structs readonly
---
 Orm/Xtensive.Orm/Orm/Entity.cs                |  24 ++---
 Orm/Xtensive.Orm/Orm/EntitySetBase.cs         |  80 +++++++-------
 .../Orm/Internals/Prefetch/EntityContainer.cs |   1 -
 .../Orm/Internals/Prefetch/EntityGroupTask.cs | 101 ++++++++----------
 .../Orm/Internals/Prefetch/EntitySetTask.cs   |  97 ++++++++---------
 .../Orm/Internals/Prefetch/PrefetchManager.cs |   4 +-
 .../Providers/SessionHandler.References.cs    |  14 +--
 .../Orm/Providers/SessionHandler.cs           |   2 -
 Orm/Xtensive.Orm/Orm/StorageNode.cs           |  29 +++--
 9 files changed, 168 insertions(+), 184 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/Entity.cs b/Orm/Xtensive.Orm/Orm/Entity.cs
index 1c301594da..5f292f7f05 100644
--- a/Orm/Xtensive.Orm/Orm/Entity.cs
+++ b/Orm/Xtensive.Orm/Orm/Entity.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2007-2020 Xtensive LLC.
+// Copyright (C) 2007-2021 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
@@ -260,22 +260,22 @@ public void RemoveLater()
       RemoveLaterInternal(EntityRemoveReason.User);
     }
 
+    private ExecutableProvider ExecutableProviderGenerator((TypeInfo typeInfo, LockMode lockMode, LockBehavior lockBehavior) t)
+    {
+      var index = t.typeInfo.Indexes.PrimaryIndex;
+      var query = index.GetQuery()
+        .Seek(context => context.GetValue(keyParameter))
+        .Lock(() => t.lockMode, () => t.lockBehavior)
+        .Select(Array.Empty<int>());
+      return Session.Compile(query);
+    }
+
     /// <inheritdoc/>
     public void Lock(LockMode lockMode, LockBehavior lockBehavior)
     {
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(keyParameter, Key.Value);
-      object key = (TypeInfo, lockMode, lockBehavior);
-      Func<object, object> generator = tripletObj => {
-        var triplet = ((TypeInfo, LockMode, LockBehavior)) tripletObj;
-        var index = triplet.Item1.Indexes.PrimaryIndex;
-        var query = index.GetQuery()
-          .Seek(context => context.GetValue(keyParameter))
-          .Lock(() => triplet.Item2, () => triplet.Item3)
-          .Select(Array.Empty<int>());
-        return Session.Compile(query);
-      };
-      var source = (ExecutableProvider) Session.StorageNode.InternalQueryCache.GetOrAdd(key, generator);
+      var source = Session.StorageNode.InternalExecutableProviderCache.GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator);
       using var recordSetReader = source.GetRecordSetReader(Session, parameterContext);
       recordSetReader.MoveNext();
     }
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index 319c3261e5..77a3e98faa 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -39,10 +39,46 @@ public abstract class EntitySetBase : SessionBound,
 #if DEBUG
     private static readonly string storageTestsAssemblyPrefix = "Xtensive.Orm.Tests";
 #endif
-    private static readonly object entitySetCachingRegion = new object();
     private static readonly Parameter<Tuple> keyParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
     internal static readonly Parameter<Entity> ownerParameter = new Parameter<Entity>("Owner");
 
+    private static readonly Func<object, EntitySetBase, EntitySetTypeState> BuildEntitySetTypeState = (object key, EntitySetBase entitySet) => {
+      var field = ((Pair<object, FieldInfo>) key).Second;
+      var association = field.Associations.Last();
+      var query = association.UnderlyingIndex.GetQuery().Seek(context => context.GetValue(keyParameter));
+      var seek = entitySet.Session.Compile(query);
+      var ownerDescriptor = association.OwnerType.Key.TupleDescriptor;
+      var targetDescriptor = association.TargetType.Key.TupleDescriptor;
+
+      var itemColumnOffsets = association.AuxiliaryType == null
+        ? association.UnderlyingIndex.ValueColumns
+            .Where(ci => ci.IsPrimaryKey)
+            .Select(ci => ci.Field.MappingInfo.Offset)
+            .ToList()
+        : Enumerable.Range(0, targetDescriptor.Count).ToList();
+
+      var keyFieldCount = ownerDescriptor.Count + itemColumnOffsets.Count;
+      var keyFieldTypes = ownerDescriptor
+        .Concat(itemColumnOffsets.Select(i => targetDescriptor[i]))
+        .ToArray(keyFieldCount);
+      var keyDescriptor = TupleDescriptor.Create(keyFieldTypes);
+
+      var map = Enumerable.Range(0, ownerDescriptor.Count)
+        .Select(i => new Pair<int, int>(0, i))
+        .Concat(itemColumnOffsets.Select(i => new Pair<int, int>(1, i)))
+        .ToArray(keyFieldCount);
+      var seekTransform = new MapTransform(true, keyDescriptor, map);
+
+      Func<Tuple, Entity> itemCtor = null;
+      if (association.AuxiliaryType != null) {
+        itemCtor = DelegateHelper.CreateDelegate<Func<Tuple, Entity>>(null,
+          association.AuxiliaryType.UnderlyingType, DelegateHelper.AspectedFactoryMethodName,
+          Array.Empty<Type>());
+      }
+
+      return new EntitySetTypeState(seek, seekTransform, itemCtor, entitySet.GetItemCountQueryDelegate(field));
+    };
+
     private readonly Entity owner;
     private readonly CombineTransform auxilaryTypeKeyTransform;
     private readonly bool skipOwnerVersionChange;
@@ -923,47 +959,7 @@ private static Key GetOwnerKey(Persistent owner)
     private EntitySetTypeState GetEntitySetTypeState()
     {
       EnsureOwnerIsNotRemoved();
-      object key = new Pair<object, FieldInfo>(entitySetCachingRegion, Field);
-      Func<object, object> generator = k => BuildEntitySetTypeState(k, this);
-      return (EntitySetTypeState) Session.StorageNode.InternalQueryCache.GetOrAdd(key, generator);
-    }
-
-    private static EntitySetTypeState BuildEntitySetTypeState(object key, EntitySetBase entitySet)
-    {
-      var field = ((Pair<object, FieldInfo>) key).Second;
-      var association = field.Associations.Last();
-      var query = association.UnderlyingIndex.GetQuery().Seek(context => context.GetValue(keyParameter));
-      var seek = entitySet.Session.Compile(query);
-      var ownerDescriptor = association.OwnerType.Key.TupleDescriptor;
-      var targetDescriptor = association.TargetType.Key.TupleDescriptor;
-
-      var itemColumnOffsets = association.AuxiliaryType == null
-        ? association.UnderlyingIndex.ValueColumns
-            .Where(ci => ci.IsPrimaryKey)
-            .Select(ci => ci.Field.MappingInfo.Offset)
-            .ToList()
-        : Enumerable.Range(0, targetDescriptor.Count).ToList();
-
-      var keyFieldCount = ownerDescriptor.Count + itemColumnOffsets.Count;
-      var keyFieldTypes = ownerDescriptor
-        .Concat(itemColumnOffsets.Select(i => targetDescriptor[i]))
-        .ToArray(keyFieldCount);
-      var keyDescriptor = TupleDescriptor.Create(keyFieldTypes);
-
-      var map = Enumerable.Range(0, ownerDescriptor.Count)
-        .Select(i => new Pair<int, int>(0, i))
-        .Concat(itemColumnOffsets.Select(i => new Pair<int, int>(1, i)))
-        .ToArray(keyFieldCount);
-      var seekTransform = new MapTransform(true, keyDescriptor, map);
-
-      Func<Tuple, Entity> itemCtor = null;
-      if (association.AuxiliaryType != null) {
-        itemCtor = DelegateHelper.CreateDelegate<Func<Tuple, Entity>>(null,
-          association.AuxiliaryType.UnderlyingType, DelegateHelper.AspectedFactoryMethodName,
-          ArrayUtils<Type>.EmptyArray);
-      }
-
-      return new EntitySetTypeState(seek, seekTransform, itemCtor, entitySet.GetItemCountQueryDelegate(field));
+      return Session.StorageNode.InternalEntitySetCache.GetOrAdd(Field, BuildEntitySetTypeState, this);
     }
 
     private int? GetItemIndex(EntitySetState state, Key key)
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
index f55332842c..065ae2c5b9 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityContainer.cs
@@ -16,7 +16,6 @@ namespace Xtensive.Orm.Internals.Prefetch
   [Serializable]
   internal abstract class EntityContainer
   {
-    private static readonly object indexSeekCachingRegion = new object();
     private static readonly Parameter<Tuple> seekParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
 
     private SortedDictionary<int, ColumnInfo> columns;
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index 16c62c6287..e34ab50556 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -15,64 +15,73 @@
 
 namespace Xtensive.Orm.Internals.Prefetch
 {
-  [Serializable]
-  internal sealed class EntityGroupTask : IEquatable<EntityGroupTask>
+  internal readonly struct RecordSetCacheKey : IEquatable<RecordSetCacheKey>
   {
-    #region Nested classes
+    public readonly int[] ColumnIndexes;
+    public readonly TypeInfo Type;
+    private readonly int cachedHashCode;
 
-    private struct CacheKey : IEquatable<CacheKey>
+    public bool Equals(RecordSetCacheKey other)
     {
-      public readonly int[] ColumnIndexes;
-      public readonly TypeInfo Type;
-      private readonly int cachedHashCode;
+      if (!Type.Equals(other.Type)) {
+        return false;
+      }
 
-      public bool Equals(CacheKey other)
-      {
-        if (!Type.Equals(other.Type)) {
-          return false;
-        }
+      if (ColumnIndexes.Length != other.ColumnIndexes.Length) {
+        return false;
+      }
 
-        if (ColumnIndexes.Length != other.ColumnIndexes.Length) {
+      for (var i = ColumnIndexes.Length - 1; i >= 0; i--) {
+        if (ColumnIndexes[i] != other.ColumnIndexes[i]) {
           return false;
         }
-
-        for (var i = ColumnIndexes.Length - 1; i >= 0; i--) {
-          if (ColumnIndexes[i] != other.ColumnIndexes[i]) {
-            return false;
-          }
-        }
-
-        return true;
       }
 
-      public override bool Equals(object obj) =>
-        obj is CacheKey other && Equals(other);
+      return true;
+    }
 
-      public override int GetHashCode() => cachedHashCode;
+    public override bool Equals(object obj) =>
+      obj is RecordSetCacheKey other && Equals(other);
 
+    public override int GetHashCode() => cachedHashCode;
 
-      // Constructors
 
-      public CacheKey(int[] columnIndexes, TypeInfo type, int cachedHashCode)
-      {
-        ColumnIndexes = columnIndexes;
-        Type = type;
-        this.cachedHashCode = cachedHashCode;
-      }
-    }
+    // Constructors
 
-    #endregion
+    public RecordSetCacheKey(int[] columnIndexes, TypeInfo type, int cachedHashCode)
+    {
+      ColumnIndexes = columnIndexes;
+      Type = type;
+      this.cachedHashCode = cachedHashCode;
+    }
+  }
 
+  [Serializable]
+  internal sealed class EntityGroupTask : IEquatable<EntityGroupTask>
+  {
     private const int MaxKeyCountInOneStatement = 40;
-    private static readonly object recordSetCachingRegion = new object();
     private static readonly Parameter<IEnumerable<Tuple>> includeParameter =
       new Parameter<IEnumerable<Tuple>>("Keys");
 
+    private static readonly Func<RecordSetCacheKey, CompilableProvider> CreateRecordSet = cachingKey => {
+      var selectedColumnIndexes = cachingKey.ColumnIndexes;
+      var keyColumnsCount = cachingKey.Type.Indexes.PrimaryIndex.KeyColumns.Count;
+      var keyColumnIndexes = new int[keyColumnsCount];
+      foreach (var index in Enumerable.Range(0, keyColumnsCount)) {
+        keyColumnIndexes[index] = index;
+      }
+
+      var columnCollectionLength = cachingKey.Type.Indexes.PrimaryIndex.Columns.Count;
+      return cachingKey.Type.Indexes.PrimaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
+        true, context => context.GetValue(includeParameter), $"includeColumnName-{Guid.NewGuid()}",
+        keyColumnIndexes).Filter(t => t.GetValue<bool>(columnCollectionLength)).Select(selectedColumnIndexes);
+    };
+
     private Dictionary<Key, bool> keys;
     private readonly TypeInfo type;
     private readonly PrefetchManager manager;
     private List<QueryTask> queryTasks;
-    private readonly CacheKey cacheKey;
+    private readonly RecordSetCacheKey cacheKey;
 
     public CompilableProvider Provider { get; private set; }
 
@@ -132,30 +141,12 @@ private QueryTask CreateQueryTask(List<Tuple> currentKeySet)
     {
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(includeParameter, currentKeySet);
-      object key = new Pair<object, CacheKey>(recordSetCachingRegion, cacheKey);
-      Func<object, object> generator = CreateRecordSet;
       var session = manager.Owner.Session;
-      Provider = (CompilableProvider) session.StorageNode.InternalQueryCache.GetOrAdd(key, generator);
+      Provider = session.StorageNode.InternalRecordSetCache.GetOrAdd(cacheKey, CreateRecordSet);
       var executableProvider = session.Compile(Provider);
       return new QueryTask(executableProvider, session.GetLifetimeToken(), parameterContext);
     }
 
-    private static CompilableProvider CreateRecordSet(object cachingKey)
-    {
-      var pair = (Pair<object, CacheKey>) cachingKey;
-      var selectedColumnIndexes = pair.Second.ColumnIndexes;
-      var keyColumnsCount = pair.Second.Type.Indexes.PrimaryIndex.KeyColumns.Count;
-      var keyColumnIndexes = new int[keyColumnsCount];
-      foreach (var index in Enumerable.Range(0, keyColumnsCount)) {
-        keyColumnIndexes[index] = index;
-      }
-
-      var columnCollectionLength = pair.Second.Type.Indexes.PrimaryIndex.Columns.Count;
-      return pair.Second.Type.Indexes.PrimaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
-        true, context => context.GetValue(includeParameter), $"includeColumnName-{Guid.NewGuid()}",
-        keyColumnIndexes).Filter(t => t.GetValue<bool>(columnCollectionLength)).Select(selectedColumnIndexes);
-    }
-
     private void PutLoadedStatesInCache(IEnumerable<Tuple> queryResult, EntityDataReader reader,
       HashSet<Key> foundedKeys)
     {
@@ -221,7 +212,7 @@ public EntityGroupTask(TypeInfo type, int[] columnIndexes, PrefetchManager manag
       }
 
       cachedHashCode ^= type.GetHashCode();
-      cacheKey = new CacheKey(columnIndexes, type, cachedHashCode);
+      cacheKey = new RecordSetCacheKey(columnIndexes, type, cachedHashCode);
     }
   }
 }
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
index 6c27b4531c..2ace149ab4 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2009-2020 Xtensive LLC.
+// Copyright (C) 2009-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Alexander Nikolaev
@@ -19,53 +19,61 @@
 
 namespace Xtensive.Orm.Internals.Prefetch
 {
-  [Serializable]
-  internal sealed class EntitySetTask : IEquatable<EntitySetTask>
+  internal readonly struct ItemsQueryCacheKey : IEquatable<ItemsQueryCacheKey>
   {
-    #region Nested classes
+    public readonly FieldInfo ReferencingField;
+    public readonly int? ItemCountLimit;
+    private readonly int cachedHashCode;
 
-    private struct CacheKey : IEquatable<CacheKey>
+    public bool Equals(ItemsQueryCacheKey other)
     {
-      public readonly FieldInfo ReferencingField;
-      public readonly int? ItemCountLimit;
-      private readonly int cachedHashCode;
-
-      public bool Equals(CacheKey other)
-      {
-        return (ItemCountLimit == null) == (other.ItemCountLimit == null)
-          && Equals(other.ReferencingField, ReferencingField);
-      }
+      return (ItemCountLimit == null) == (other.ItemCountLimit == null)
+        && Equals(other.ReferencingField, ReferencingField);
+    }
 
-      public override bool Equals(object obj) =>
-        obj is CacheKey other && Equals(other);
+    public override bool Equals(object obj) =>
+      obj is ItemsQueryCacheKey other && Equals(other);
 
-      public override int GetHashCode() => cachedHashCode;
+    public override int GetHashCode() => cachedHashCode;
 
-      // Constructors
+    // Constructors
 
-      public CacheKey(FieldInfo referencingField, int? itemCountLimit)
-      {
-        ReferencingField = referencingField;
-        ItemCountLimit = itemCountLimit;
-        unchecked {
-          cachedHashCode = (ReferencingField.GetHashCode()*397)
-                           ^ (ItemCountLimit.HasValue ? 1 : 0);
-        }
+    public ItemsQueryCacheKey(FieldInfo referencingField, int? itemCountLimit)
+    {
+      ReferencingField = referencingField;
+      ItemCountLimit = itemCountLimit;
+      unchecked {
+        cachedHashCode = (ReferencingField.GetHashCode() * 397)
+                         ^ (ItemCountLimit.HasValue ? 1 : 0);
       }
     }
+  }
 
-    #endregion
-
-    private static readonly object itemsQueryCachingRegion = new object();
+  [Serializable]
+  internal sealed class EntitySetTask : IEquatable<EntitySetTask>
+  {
     private static readonly Parameter<Tuple> ownerParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
     private static readonly Parameter<int> itemCountLimitParameter = new Parameter<int>("ItemCountLimit");
 
+    private static readonly Func<ItemsQueryCacheKey, CompilableProvider> CreateRecordSetLoadingItems = cachingKey => {
+      var association = cachingKey.ReferencingField.Associations.Last();
+      var primaryTargetIndex = association.TargetType.Indexes.PrimaryIndex;
+      var resultColumns = new List<int>(primaryTargetIndex.Columns.Count);
+      var result = association.AuxiliaryType == null
+        ? CreateQueryForDirectAssociation(cachingKey, primaryTargetIndex, resultColumns)
+        : CreateQueryForAssociationViaAuxType(cachingKey, primaryTargetIndex, resultColumns);
+      result = result.Select(resultColumns);
+      if (cachingKey.ItemCountLimit != null)
+        result = result.Take(context => context.GetValue(itemCountLimitParameter));
+      return result;
+    };
+
     private readonly Key ownerKey;
     private readonly bool isOwnerCached;
     private readonly PrefetchManager manager;
     private QueryTask itemsQueryTask;
     private readonly PrefetchFieldDescriptor referencingFieldDescriptor;
-    private readonly CacheKey cacheKey;
+    private readonly ItemsQueryCacheKey cacheKey;
 
     public FieldInfo ReferencingField {get { return referencingFieldDescriptor.Field; } }
 
@@ -166,11 +174,9 @@ private QueryTask CreateQueryTask()
         parameterContext.SetValue(itemCountLimitParameter, ItemCountLimit.Value);
       }
 
-      object key = new Pair<object, CacheKey>(itemsQueryCachingRegion, cacheKey);
-      Func<object, object> generator = CreateRecordSetLoadingItems;
       var session = manager.Owner.Session;
       var scope = new CompiledQueryProcessingScope(null, null, parameterContext, false);
-      QueryProvider = (CompilableProvider) session.StorageNode.InternalQueryCache.GetOrAdd(key, generator);
+      QueryProvider = session.StorageNode.InternalItemsQueryCache.GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
       ExecutableProvider executableProvider;
       using (scope.Enter()) {
         executableProvider = session.Compile(QueryProvider);
@@ -178,24 +184,9 @@ private QueryTask CreateQueryTask()
       return new QueryTask(executableProvider, session.GetLifetimeToken(), parameterContext);
     }
 
-    private static CompilableProvider CreateRecordSetLoadingItems(object cachingKey)
-    {
-      var pair = (Pair<object, CacheKey>) cachingKey;
-      var association = pair.Second.ReferencingField.Associations.Last();
-      var primaryTargetIndex = association.TargetType.Indexes.PrimaryIndex;
-      var resultColumns = new List<int>(primaryTargetIndex.Columns.Count);
-      var result = association.AuxiliaryType == null
-        ? CreateQueryForDirectAssociation(pair, primaryTargetIndex, resultColumns)
-        : CreateQueryForAssociationViaAuxType(pair, primaryTargetIndex, resultColumns);
-      result = result.Select(resultColumns);
-      if (pair.Second.ItemCountLimit != null)
-        result = result.Take(context => context.GetValue(itemCountLimitParameter));
-      return result;
-    }
-
-    private static CompilableProvider CreateQueryForAssociationViaAuxType(Pair<object, CacheKey> pair, IndexInfo primaryTargetIndex, List<int> resultColumns)
+    private static CompilableProvider CreateQueryForAssociationViaAuxType(in ItemsQueryCacheKey cachingKey, IndexInfo primaryTargetIndex, List<int> resultColumns)
     {
-      var association = pair.Second.ReferencingField.Associations.Last();
+      var association = cachingKey.ReferencingField.Associations.Last();
       var associationIndex = association.UnderlyingIndex;
       var joiningColumns = GetJoiningColumnIndexes(primaryTargetIndex, associationIndex,
         association.AuxiliaryType != null);
@@ -214,10 +205,10 @@ private static CompilableProvider CreateQueryForAssociationViaAuxType(Pair<objec
         .Join(primaryTargetIndex.GetQuery(), joiningColumns);
     }
 
-    private static CompilableProvider CreateQueryForDirectAssociation(Pair<object, CacheKey> pair, IndexInfo primaryTargetIndex, List<int> resultColumns)
+    private static CompilableProvider CreateQueryForDirectAssociation(in ItemsQueryCacheKey cachingKey, IndexInfo primaryTargetIndex, List<int> resultColumns)
     {
       AddResultColumnIndexes(resultColumns, primaryTargetIndex, 0);
-      var association = pair.Second.ReferencingField.Associations.Last();
+      var association = cachingKey.ReferencingField.Associations.Last();
       var field = association.Reversed.OwnerField;
       var keyColumnTypes = field.Columns.Select(column => column.ValueType).ToList();
       return primaryTargetIndex
@@ -273,7 +264,7 @@ public EntitySetTask(Key ownerKey, PrefetchFieldDescriptor referencingFieldDescr
       this.isOwnerCached = isOwnerCached;
       ItemCountLimit = referencingFieldDescriptor.EntitySetItemCountLimit;
       this.manager = manager;
-      cacheKey = new CacheKey(ReferencingField, ItemCountLimit);
+      cacheKey = new ItemsQueryCacheKey(ReferencingField, ItemCountLimit);
     }
   }
 }
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
index ad8a903ed3..f6c07406ee 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/PrefetchManager.cs
@@ -22,7 +22,7 @@ internal sealed class PrefetchManager
   {
     #region Nested classes
 
-    private struct RootContainerCacheKey : IEquatable<RootContainerCacheKey>
+    private readonly struct RootContainerCacheKey : IEquatable<RootContainerCacheKey>
     {
       private readonly int hashCode;
 
@@ -69,7 +69,7 @@ private class RootContainerCacheEntry
 
       // Constructors
 
-      public RootContainerCacheEntry(RootContainerCacheKey key, SortedDictionary<int, ColumnInfo> columns,
+      public RootContainerCacheEntry(in RootContainerCacheKey key, SortedDictionary<int, ColumnInfo> columns,
         List<int> columnsToBeLoaded)
       {
         Key = key;
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
index 0764c26b1d..e2448f2b9a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2009-2020 Xtensive LLC.
+// Copyright (C) 2009-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Denis Krjuchkov
@@ -29,11 +29,7 @@ public virtual IEnumerable<ReferenceInfo> GetReferencesTo(Entity target, Associa
     {
       if (association.IsPaired)
         return FindReferences(target, association, true);
-      object key = new Pair<object, AssociationInfo>(CachingRegion, association);
-      Func<object, object> generator = p => BuildReferencingQuery(((Pair<object, AssociationInfo>) p).Second);
-      var pair = (Pair<CompilableProvider, Parameter<Tuple>>) Session.StorageNode.InternalQueryCache.GetOrAdd(key, generator);
-      var recordSet = pair.First;
-      var parameter = pair.Second;
+      var (recordSet, parameter) = Session.StorageNode.InternalAssociationCache.GetOrAdd(association, BuildReferencingQuery);
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(parameter, target.Key.Value);
       ExecutableProvider executableProvider = Session.Compile(recordSet);
@@ -94,7 +90,7 @@ private static IEnumerable<ReferenceInfo> FindReferences(Entity owner, Associati
       }
     }
 
-    private static Pair<CompilableProvider, Parameter<Tuple>> BuildReferencingQuery(AssociationInfo association)
+    private static (CompilableProvider, Parameter<Tuple>) BuildReferencingQuery(AssociationInfo association)
     {
       var provider = (CompilableProvider)null;
       var parameter = new Parameter<Tuple>("pTuple");
@@ -178,7 +174,7 @@ private static Pair<CompilableProvider, Parameter<Tuple>> BuildReferencingQuery(
           break;
         }
       }
-      return new Pair<CompilableProvider, Parameter<Tuple>>(provider, parameter);
+      return (provider, parameter);
     }
   }
-}
\ No newline at end of file
+}
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
index b2fb2c7854..e6b4abfe9e 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.cs
@@ -19,8 +19,6 @@ namespace Xtensive.Orm.Providers
   /// </summary>
   public abstract partial class SessionHandler : IDisposable, IAsyncDisposable
   {
-    private static readonly object CachingRegion = new object();
-
     /// <summary>
     /// Gets <see cref="HandlerAccessor"/>.
     /// </summary>
diff --git a/Orm/Xtensive.Orm/Orm/StorageNode.cs b/Orm/Xtensive.Orm/Orm/StorageNode.cs
index 719476000e..d5c399e392 100644
--- a/Orm/Xtensive.Orm/Orm/StorageNode.cs
+++ b/Orm/Xtensive.Orm/Orm/StorageNode.cs
@@ -1,4 +1,4 @@
-// Copyright (C) 2014-2020 Xtensive LLC.
+// Copyright (C) 2014-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Denis Krjuchkov
@@ -14,6 +14,9 @@
 using Xtensive.Orm.Interfaces;
 using Xtensive.Orm.Model;
 using Xtensive.Orm.Providers;
+using Xtensive.Orm.Rse.Providers;
+using Xtensive.Orm.Internals;
+using Xtensive.Orm.Internals.Prefetch;
 
 namespace Xtensive.Orm
 {
@@ -44,11 +47,25 @@ public sealed class StorageNode : ISessionSource
     /// </summary>
     public TypeIdRegistry TypeIdRegistry { get; private set; }
 
-    internal ConcurrentDictionary<object, object> InternalQueryCache { get; private set; }
+    internal ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider> InternalExecutableProviderCache { get; } =
+      new ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider>();
 
-    internal ConcurrentDictionary<SequenceInfo, object> KeySequencesCache { get; private set; }
+    internal ConcurrentDictionary<RecordSetCacheKey, CompilableProvider> InternalRecordSetCache { get; } =
+      new ConcurrentDictionary<RecordSetCacheKey, CompilableProvider>();
 
-    internal ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>> PersistRequestCache { get; private set; }
+    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> InternalItemsQueryCache { get; } =
+      new ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider>();
+
+    internal ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState> InternalEntitySetCache { get; } =
+      new ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState>();
+
+    internal ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)> InternalAssociationCache { get; } =
+      new ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)>();
+
+    internal ConcurrentDictionary<SequenceInfo, object> KeySequencesCache { get; } = new ConcurrentDictionary<SequenceInfo, object>();
+
+    internal ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>> PersistRequestCache { get; }
+      = new ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>>();
 
     /// <inheritdoc/>
     public Session OpenSession()
@@ -121,10 +138,6 @@ internal StorageNode(Domain domain, NodeConfiguration configuration, ModelMappin
       Configuration = configuration;
       Mapping = mapping;
       TypeIdRegistry = typeIdRegistry;
-
-      KeySequencesCache = new ConcurrentDictionary<SequenceInfo, object>();
-      PersistRequestCache = new ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>>();
-      InternalQueryCache = new ConcurrentDictionary<object, object>();
     }
   }
 }

From 94c2daab88e131991d7c3354e4313c4824501327 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Wed, 24 Nov 2021 00:21:12 -0800
Subject: [PATCH 02/12] Typecast bugfix of BuildEntitySetTypeState

---
 Orm/Xtensive.Orm/Orm/EntitySetBase.cs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index 77a3e98faa..b9f3a8744e 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -42,8 +42,7 @@ public abstract class EntitySetBase : SessionBound,
     private static readonly Parameter<Tuple> keyParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
     internal static readonly Parameter<Entity> ownerParameter = new Parameter<Entity>("Owner");
 
-    private static readonly Func<object, EntitySetBase, EntitySetTypeState> BuildEntitySetTypeState = (object key, EntitySetBase entitySet) => {
-      var field = ((Pair<object, FieldInfo>) key).Second;
+    private static readonly Func<FieldInfo, EntitySetBase, EntitySetTypeState> BuildEntitySetTypeState = (FieldInfo field, EntitySetBase entitySet) => {
       var association = field.Associations.Last();
       var query = association.UnderlyingIndex.GetQuery().Seek(context => context.GetValue(keyParameter));
       var seek = entitySet.Session.Compile(query);

From 970aa4a8c25043e474a4c15f1a37fafe06a9bacf Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 08:58:06 -0800
Subject: [PATCH 03/12] Make ExecutableProviderGenerator static readonly Func

---
 Orm/Xtensive.Orm/Orm/Entity.cs | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/Entity.cs b/Orm/Xtensive.Orm/Orm/Entity.cs
index 5f292f7f05..85e1e9b6db 100644
--- a/Orm/Xtensive.Orm/Orm/Entity.cs
+++ b/Orm/Xtensive.Orm/Orm/Entity.cs
@@ -66,6 +66,12 @@ public abstract class Entity : Persistent,
     ISerializable,
     IDeserializationCallback
   {
+    private static readonly Func<(TypeInfo typeInfo, LockMode lockMode, LockBehavior lockBehavior), Session, ExecutableProvider> ExecutableProviderGenerator = ((TypeInfo typeInfo, LockMode lockMode, LockBehavior lockBehavior) t, Session session) =>
+      session.Compile(t.typeInfo.Indexes.PrimaryIndex.GetQuery()
+        .Seek(context => context.GetValue(keyParameter))
+        .Lock(() => t.lockMode, () => t.lockBehavior)
+        .Select(Array.Empty<int>()));
+
     private static readonly Parameter<Tuple> keyParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
     private readonly bool changeVersionOnSetAttempt;
     private EntityState state;
@@ -260,22 +266,12 @@ public void RemoveLater()
       RemoveLaterInternal(EntityRemoveReason.User);
     }
 
-    private ExecutableProvider ExecutableProviderGenerator((TypeInfo typeInfo, LockMode lockMode, LockBehavior lockBehavior) t)
-    {
-      var index = t.typeInfo.Indexes.PrimaryIndex;
-      var query = index.GetQuery()
-        .Seek(context => context.GetValue(keyParameter))
-        .Lock(() => t.lockMode, () => t.lockBehavior)
-        .Select(Array.Empty<int>());
-      return Session.Compile(query);
-    }
-
     /// <inheritdoc/>
     public void Lock(LockMode lockMode, LockBehavior lockBehavior)
     {
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(keyParameter, Key.Value);
-      var source = Session.StorageNode.InternalExecutableProviderCache.GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator);
+      var source = Session.StorageNode.InternalExecutableProviderCache.GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator, Session);
       using var recordSetReader = source.GetRecordSetReader(Session, parameterContext);
       recordSetReader.MoveNext();
     }

From 24ddd41855d444af7531fb3b7122932624670a32 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 09:06:26 -0800
Subject: [PATCH 04/12] privaryIndex var in CreateRecordSet

---
 Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index e34ab50556..e19090cccd 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -65,13 +65,14 @@ internal sealed class EntityGroupTask : IEquatable<EntityGroupTask>
 
     private static readonly Func<RecordSetCacheKey, CompilableProvider> CreateRecordSet = cachingKey => {
       var selectedColumnIndexes = cachingKey.ColumnIndexes;
-      var keyColumnsCount = cachingKey.Type.Indexes.PrimaryIndex.KeyColumns.Count;
+      var privaryIndex = cachingKey.Type.Indexes.PrimaryIndex;
+      var keyColumnsCount = privaryIndex.KeyColumns.Count;
       var keyColumnIndexes = new int[keyColumnsCount];
       foreach (var index in Enumerable.Range(0, keyColumnsCount)) {
         keyColumnIndexes[index] = index;
       }
 
-      var columnCollectionLength = cachingKey.Type.Indexes.PrimaryIndex.Columns.Count;
+      var columnCollectionLength = privaryIndex.Columns.Count;
       return cachingKey.Type.Indexes.PrimaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
         true, context => context.GetValue(includeParameter), $"includeColumnName-{Guid.NewGuid()}",
         keyColumnIndexes).Filter(t => t.GetValue<bool>(columnCollectionLength)).Select(selectedColumnIndexes);

From 9c5f79c41b1547b236677689d5662be483226862 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 09:07:56 -0800
Subject: [PATCH 05/12] privaryIndex var in CreateRecordSet

---
 Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index e19090cccd..543de99328 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -73,7 +73,7 @@ internal sealed class EntityGroupTask : IEquatable<EntityGroupTask>
       }
 
       var columnCollectionLength = privaryIndex.Columns.Count;
-      return cachingKey.Type.Indexes.PrimaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
+      return privaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
         true, context => context.GetValue(includeParameter), $"includeColumnName-{Guid.NewGuid()}",
         keyColumnIndexes).Filter(t => t.GetValue<bool>(columnCollectionLength)).Select(selectedColumnIndexes);
     };

From 9b66a456e76fbabe3cbebd3eaaf76fd40d509c9c Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 09:12:49 -0800
Subject: [PATCH 06/12] Refactor BuildEntitySetTypeState

---
 Orm/Xtensive.Orm/Orm/EntitySetBase.cs | 75 ++++++++++++++-------------
 1 file changed, 39 insertions(+), 36 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index b9f3a8744e..da58554e9f 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -42,41 +42,7 @@ public abstract class EntitySetBase : SessionBound,
     private static readonly Parameter<Tuple> keyParameter = new Parameter<Tuple>(WellKnown.KeyFieldName);
     internal static readonly Parameter<Entity> ownerParameter = new Parameter<Entity>("Owner");
 
-    private static readonly Func<FieldInfo, EntitySetBase, EntitySetTypeState> BuildEntitySetTypeState = (FieldInfo field, EntitySetBase entitySet) => {
-      var association = field.Associations.Last();
-      var query = association.UnderlyingIndex.GetQuery().Seek(context => context.GetValue(keyParameter));
-      var seek = entitySet.Session.Compile(query);
-      var ownerDescriptor = association.OwnerType.Key.TupleDescriptor;
-      var targetDescriptor = association.TargetType.Key.TupleDescriptor;
-
-      var itemColumnOffsets = association.AuxiliaryType == null
-        ? association.UnderlyingIndex.ValueColumns
-            .Where(ci => ci.IsPrimaryKey)
-            .Select(ci => ci.Field.MappingInfo.Offset)
-            .ToList()
-        : Enumerable.Range(0, targetDescriptor.Count).ToList();
-
-      var keyFieldCount = ownerDescriptor.Count + itemColumnOffsets.Count;
-      var keyFieldTypes = ownerDescriptor
-        .Concat(itemColumnOffsets.Select(i => targetDescriptor[i]))
-        .ToArray(keyFieldCount);
-      var keyDescriptor = TupleDescriptor.Create(keyFieldTypes);
-
-      var map = Enumerable.Range(0, ownerDescriptor.Count)
-        .Select(i => new Pair<int, int>(0, i))
-        .Concat(itemColumnOffsets.Select(i => new Pair<int, int>(1, i)))
-        .ToArray(keyFieldCount);
-      var seekTransform = new MapTransform(true, keyDescriptor, map);
-
-      Func<Tuple, Entity> itemCtor = null;
-      if (association.AuxiliaryType != null) {
-        itemCtor = DelegateHelper.CreateDelegate<Func<Tuple, Entity>>(null,
-          association.AuxiliaryType.UnderlyingType, DelegateHelper.AspectedFactoryMethodName,
-          Array.Empty<Type>());
-      }
-
-      return new EntitySetTypeState(seek, seekTransform, itemCtor, entitySet.GetItemCountQueryDelegate(field));
-    };
+    private static readonly Func<FieldInfo, EntitySetBase, EntitySetTypeState> EntitySetTypeStateFactory = BuildEntitySetTypeState;
 
     private readonly Entity owner;
     private readonly CombineTransform auxilaryTypeKeyTransform;
@@ -958,7 +924,44 @@ private static Key GetOwnerKey(Persistent owner)
     private EntitySetTypeState GetEntitySetTypeState()
     {
       EnsureOwnerIsNotRemoved();
-      return Session.StorageNode.InternalEntitySetCache.GetOrAdd(Field, BuildEntitySetTypeState, this);
+      return Session.StorageNode.InternalEntitySetCache.GetOrAdd(Field, EntitySetTypeStateFactory, this);
+    }
+
+    private static EntitySetTypeState BuildEntitySetTypeState(FieldInfo field, EntitySetBase entitySet)
+    {
+      var association = field.Associations.Last();
+      var query = association.UnderlyingIndex.GetQuery().Seek(context => context.GetValue(keyParameter));
+      var seek = entitySet.Session.Compile(query);
+      var ownerDescriptor = association.OwnerType.Key.TupleDescriptor;
+      var targetDescriptor = association.TargetType.Key.TupleDescriptor;
+
+      var itemColumnOffsets = association.AuxiliaryType == null
+        ? association.UnderlyingIndex.ValueColumns
+            .Where(ci => ci.IsPrimaryKey)
+            .Select(ci => ci.Field.MappingInfo.Offset)
+            .ToList()
+        : Enumerable.Range(0, targetDescriptor.Count).ToList();
+
+      var keyFieldCount = ownerDescriptor.Count + itemColumnOffsets.Count;
+      var keyFieldTypes = ownerDescriptor
+        .Concat(itemColumnOffsets.Select(i => targetDescriptor[i]))
+        .ToArray(keyFieldCount);
+      var keyDescriptor = TupleDescriptor.Create(keyFieldTypes);
+
+      var map = Enumerable.Range(0, ownerDescriptor.Count)
+        .Select(i => new Pair<int, int>(0, i))
+        .Concat(itemColumnOffsets.Select(i => new Pair<int, int>(1, i)))
+        .ToArray(keyFieldCount);
+      var seekTransform = new MapTransform(true, keyDescriptor, map);
+
+      Func<Tuple, Entity> itemCtor = null;
+      if (association.AuxiliaryType != null) {
+        itemCtor = DelegateHelper.CreateDelegate<Func<Tuple, Entity>>(null,
+          association.AuxiliaryType.UnderlyingType, DelegateHelper.AspectedFactoryMethodName,
+          Array.Empty<Type>());
+      }
+
+      return new EntitySetTypeState(seek, seekTransform, itemCtor, entitySet.GetItemCountQueryDelegate(field));
     }
 
     private int? GetItemIndex(EntitySetState state, Key key)

From 290e27e4418243618794d8a4eb3a2cc62dedad0c Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 09:19:15 -0800
Subject: [PATCH 07/12] Rename internal cache names, add comments

---
 Orm/Xtensive.Orm/Orm/Entity.cs                |  2 +-
 Orm/Xtensive.Orm/Orm/EntitySetBase.cs         |  2 +-
 .../Orm/Internals/Prefetch/EntityGroupTask.cs |  2 +-
 .../Orm/Internals/Prefetch/EntitySetTask.cs   |  2 +-
 .../Providers/SessionHandler.References.cs    |  2 +-
 Orm/Xtensive.Orm/Orm/StorageNode.cs           | 25 +++++++++++++++----
 6 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/Entity.cs b/Orm/Xtensive.Orm/Orm/Entity.cs
index 85e1e9b6db..5d5aafc5f8 100644
--- a/Orm/Xtensive.Orm/Orm/Entity.cs
+++ b/Orm/Xtensive.Orm/Orm/Entity.cs
@@ -271,7 +271,7 @@ public void Lock(LockMode lockMode, LockBehavior lockBehavior)
     {
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(keyParameter, Key.Value);
-      var source = Session.StorageNode.InternalExecutableProviderCache.GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator, Session);
+      var source = Session.StorageNode.EntityLockProviderCache .GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator, Session);
       using var recordSetReader = source.GetRecordSetReader(Session, parameterContext);
       recordSetReader.MoveNext();
     }
diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index da58554e9f..9469c8d219 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -924,7 +924,7 @@ private static Key GetOwnerKey(Persistent owner)
     private EntitySetTypeState GetEntitySetTypeState()
     {
       EnsureOwnerIsNotRemoved();
-      return Session.StorageNode.InternalEntitySetCache.GetOrAdd(Field, EntitySetTypeStateFactory, this);
+      return Session.StorageNode.EntitySetTypeStateCache .GetOrAdd(Field, EntitySetTypeStateFactory, this);
     }
 
     private static EntitySetTypeState BuildEntitySetTypeState(FieldInfo field, EntitySetBase entitySet)
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index 543de99328..96870e7282 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -143,7 +143,7 @@ private QueryTask CreateQueryTask(List<Tuple> currentKeySet)
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(includeParameter, currentKeySet);
       var session = manager.Owner.Session;
-      Provider = session.StorageNode.InternalRecordSetCache.GetOrAdd(cacheKey, CreateRecordSet);
+      Provider = session.StorageNode.EntityFetchQueryCache.GetOrAdd(cacheKey, CreateRecordSet);
       var executableProvider = session.Compile(Provider);
       return new QueryTask(executableProvider, session.GetLifetimeToken(), parameterContext);
     }
diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
index 2ace149ab4..21abc20593 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
@@ -176,7 +176,7 @@ private QueryTask CreateQueryTask()
 
       var session = manager.Owner.Session;
       var scope = new CompiledQueryProcessingScope(null, null, parameterContext, false);
-      QueryProvider = session.StorageNode.InternalItemsQueryCache.GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
+      QueryProvider = session.StorageNode.EntitySetFetchQueryCache .GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
       ExecutableProvider executableProvider;
       using (scope.Enter()) {
         executableProvider = session.Compile(QueryProvider);
diff --git a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
index e2448f2b9a..29049f402a 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/SessionHandler.References.cs
@@ -29,7 +29,7 @@ public virtual IEnumerable<ReferenceInfo> GetReferencesTo(Entity target, Associa
     {
       if (association.IsPaired)
         return FindReferences(target, association, true);
-      var (recordSet, parameter) = Session.StorageNode.InternalAssociationCache.GetOrAdd(association, BuildReferencingQuery);
+      var (recordSet, parameter) = Session.StorageNode.RefsToEntityQueryCache .GetOrAdd(association, BuildReferencingQuery);
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(parameter, target.Key.Value);
       ExecutableProvider executableProvider = Session.Compile(recordSet);
diff --git a/Orm/Xtensive.Orm/Orm/StorageNode.cs b/Orm/Xtensive.Orm/Orm/StorageNode.cs
index d5c399e392..412a8c6d9e 100644
--- a/Orm/Xtensive.Orm/Orm/StorageNode.cs
+++ b/Orm/Xtensive.Orm/Orm/StorageNode.cs
@@ -47,19 +47,34 @@ public sealed class StorageNode : ISessionSource
     /// </summary>
     public TypeIdRegistry TypeIdRegistry { get; private set; }
 
-    internal ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider> InternalExecutableProviderCache { get; } =
+    /// <summary>
+    /// Caches providers that lock certain type of entity with certain <see cref="LockMode"/> and <see cref="LockBehavior"/>.
+    /// </summary>
+    internal ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider> EntityLockProviderCache { get; } =
       new ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider>();
 
-    internal ConcurrentDictionary<RecordSetCacheKey, CompilableProvider> InternalRecordSetCache { get; } =
+    /// <summary>
+    /// Caches uncompiled queries used by <see cref="PrefetchManager"/> to fetch certain entities.
+    /// </summary>
+    internal ConcurrentDictionary<RecordSetCacheKey, CompilableProvider> EntityFetchQueryCache { get; } =
       new ConcurrentDictionary<RecordSetCacheKey, CompilableProvider>();
 
-    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> InternalItemsQueryCache { get; } =
+    /// <summary>
+    /// Caches uncompiled queries used by <see cref="PrefetchManager"/> to fetch <see cref="EntitySet{TItem}"/> content.
+    /// </summary>
+    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> EntitySetFetchQueryCache { get; } =
       new ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider>();
 
-    internal ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState> InternalEntitySetCache { get; } =
+    /// <summary>
+    /// Caches certain info about EntitySet fields, e.g. queries to fetch current count or items.
+    /// </summary>
+    internal ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState> EntitySetTypeStateCache { get; } =
       new ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState>();
 
-    internal ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)> InternalAssociationCache { get; } =
+    /// <summary>
+    /// Caches queries that get references to entities for certain association.
+    /// </summary>
+    internal ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)> RefsToEntityQueryCache { get; } =
       new ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)>();
 
     internal ConcurrentDictionary<SequenceInfo, object> KeySequencesCache { get; } = new ConcurrentDictionary<SequenceInfo, object>();

From d186c2c8766cd8da1fa08babe7999503e16d96e8 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Fri, 10 Dec 2021 09:24:07 -0800
Subject: [PATCH 08/12] Move internal caches inititalization into constructor

---
 Orm/Xtensive.Orm/Orm/StorageNode.cs | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/StorageNode.cs b/Orm/Xtensive.Orm/Orm/StorageNode.cs
index 412a8c6d9e..7ee02aa967 100644
--- a/Orm/Xtensive.Orm/Orm/StorageNode.cs
+++ b/Orm/Xtensive.Orm/Orm/StorageNode.cs
@@ -50,37 +50,29 @@ public sealed class StorageNode : ISessionSource
     /// <summary>
     /// Caches providers that lock certain type of entity with certain <see cref="LockMode"/> and <see cref="LockBehavior"/>.
     /// </summary>
-    internal ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider> EntityLockProviderCache { get; } =
-      new ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider>();
+    internal ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider> EntityLockProviderCache { get; }
 
     /// <summary>
     /// Caches uncompiled queries used by <see cref="PrefetchManager"/> to fetch certain entities.
     /// </summary>
-    internal ConcurrentDictionary<RecordSetCacheKey, CompilableProvider> EntityFetchQueryCache { get; } =
-      new ConcurrentDictionary<RecordSetCacheKey, CompilableProvider>();
+    internal ConcurrentDictionary<RecordSetCacheKey, CompilableProvider> EntityFetchQueryCache { get; }
 
     /// <summary>
     /// Caches uncompiled queries used by <see cref="PrefetchManager"/> to fetch <see cref="EntitySet{TItem}"/> content.
     /// </summary>
-    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> EntitySetFetchQueryCache { get; } =
-      new ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider>();
+    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> EntitySetFetchQueryCache { get; }
 
     /// <summary>
     /// Caches certain info about EntitySet fields, e.g. queries to fetch current count or items.
     /// </summary>
-    internal ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState> EntitySetTypeStateCache { get; } =
-      new ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState>();
+    internal ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState> EntitySetTypeStateCache { get; }
 
     /// <summary>
     /// Caches queries that get references to entities for certain association.
     /// </summary>
-    internal ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)> RefsToEntityQueryCache { get; } =
-      new ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)>();
-
-    internal ConcurrentDictionary<SequenceInfo, object> KeySequencesCache { get; } = new ConcurrentDictionary<SequenceInfo, object>();
-
+    internal ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)> RefsToEntityQueryCache { get; }
+    internal ConcurrentDictionary<SequenceInfo, object> KeySequencesCache { get; }
     internal ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>> PersistRequestCache { get; }
-      = new ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>>();
 
     /// <inheritdoc/>
     public Session OpenSession()
@@ -149,6 +141,14 @@ internal StorageNode(Domain domain, NodeConfiguration configuration, ModelMappin
       ArgumentValidator.EnsureArgumentNotNull(mapping, nameof(mapping));
       ArgumentValidator.EnsureArgumentNotNull(typeIdRegistry, nameof(typeIdRegistry));
 
+      EntityLockProviderCache = new ConcurrentDictionary<(TypeInfo, LockMode, LockBehavior), ExecutableProvider>();
+      EntityFetchQueryCache = new ConcurrentDictionary<RecordSetCacheKey, CompilableProvider>();
+      EntitySetFetchQueryCache = new ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider>();
+      EntitySetTypeStateCache = new ConcurrentDictionary<Xtensive.Orm.Model.FieldInfo, EntitySetTypeState>();
+      RefsToEntityQueryCache = new ConcurrentDictionary<AssociationInfo, (CompilableProvider, Parameter<Xtensive.Tuples.Tuple>)>();
+      KeySequencesCache = new ConcurrentDictionary<SequenceInfo, object>();
+      PersistRequestCache = new ConcurrentDictionary<PersistRequestBuilderTask, ICollection<PersistRequest>>();
+
       this.domain = domain;
       Configuration = configuration;
       Mapping = mapping;

From 1943e18090045604c2e926bcfb7210ac5e28d360 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Mon, 13 Dec 2021 11:36:44 -0800
Subject: [PATCH 09/12] Update
 Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs

Co-authored-by: Alexey Kulakov <alexey.kulakov@dataobjects.net>
---
 .../Orm/Internals/Prefetch/EntityGroupTask.cs             | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
index 96870e7282..f4b745d900 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntityGroupTask.cs
@@ -65,15 +65,15 @@ internal sealed class EntityGroupTask : IEquatable<EntityGroupTask>
 
     private static readonly Func<RecordSetCacheKey, CompilableProvider> CreateRecordSet = cachingKey => {
       var selectedColumnIndexes = cachingKey.ColumnIndexes;
-      var privaryIndex = cachingKey.Type.Indexes.PrimaryIndex;
-      var keyColumnsCount = privaryIndex.KeyColumns.Count;
+      var primaryIndex = cachingKey.Type.Indexes.PrimaryIndex;
+      var keyColumnsCount = primaryIndex.KeyColumns.Count;
       var keyColumnIndexes = new int[keyColumnsCount];
       foreach (var index in Enumerable.Range(0, keyColumnsCount)) {
         keyColumnIndexes[index] = index;
       }
 
-      var columnCollectionLength = privaryIndex.Columns.Count;
-      return privaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
+      var columnCollectionLength = primaryIndex.Columns.Count;
+      return primaryIndex.GetQuery().Include(IncludeAlgorithm.ComplexCondition,
         true, context => context.GetValue(includeParameter), $"includeColumnName-{Guid.NewGuid()}",
         keyColumnIndexes).Filter(t => t.GetValue<bool>(columnCollectionLength)).Select(selectedColumnIndexes);
     };

From f1810f6ec0f482da8b182be562e801f9cf5643c4 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Tue, 14 Dec 2021 23:13:17 -0800
Subject: [PATCH 10/12] Update Orm/Xtensive.Orm/Orm/Entity.cs

Co-authored-by: Alexey Kulakov <alexey.kulakov@dataobjects.net>
---
 Orm/Xtensive.Orm/Orm/Entity.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Orm/Xtensive.Orm/Orm/Entity.cs b/Orm/Xtensive.Orm/Orm/Entity.cs
index 5d5aafc5f8..0c65643a1b 100644
--- a/Orm/Xtensive.Orm/Orm/Entity.cs
+++ b/Orm/Xtensive.Orm/Orm/Entity.cs
@@ -271,7 +271,7 @@ public void Lock(LockMode lockMode, LockBehavior lockBehavior)
     {
       var parameterContext = new ParameterContext();
       parameterContext.SetValue(keyParameter, Key.Value);
-      var source = Session.StorageNode.EntityLockProviderCache .GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator, Session);
+      var source = Session.StorageNode.EntityLockProviderCache.GetOrAdd((TypeInfo, lockMode, lockBehavior), ExecutableProviderGenerator, Session);
       using var recordSetReader = source.GetRecordSetReader(Session, parameterContext);
       recordSetReader.MoveNext();
     }

From 8728dfa9a87dacc14281ef6ea6afa4287d8101f9 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Tue, 14 Dec 2021 23:13:27 -0800
Subject: [PATCH 11/12] Update Orm/Xtensive.Orm/Orm/EntitySetBase.cs

Co-authored-by: Alexey Kulakov <alexey.kulakov@dataobjects.net>
---
 Orm/Xtensive.Orm/Orm/EntitySetBase.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
index 9469c8d219..e8c2795ffa 100644
--- a/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
+++ b/Orm/Xtensive.Orm/Orm/EntitySetBase.cs
@@ -924,7 +924,7 @@ private static Key GetOwnerKey(Persistent owner)
     private EntitySetTypeState GetEntitySetTypeState()
     {
       EnsureOwnerIsNotRemoved();
-      return Session.StorageNode.EntitySetTypeStateCache .GetOrAdd(Field, EntitySetTypeStateFactory, this);
+      return Session.StorageNode.EntitySetTypeStateCache.GetOrAdd(Field, EntitySetTypeStateFactory, this);
     }
 
     private static EntitySetTypeState BuildEntitySetTypeState(FieldInfo field, EntitySetBase entitySet)

From 1d70379bb9ff97dae355303731157a44845305f8 Mon Sep 17 00:00:00 2001
From: Sergei Pavlov <spavlov@servicetitan.com>
Date: Tue, 14 Dec 2021 23:13:35 -0800
Subject: [PATCH 12/12] Update
 Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs

Co-authored-by: Alexey Kulakov <alexey.kulakov@dataobjects.net>
---
 Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
index 21abc20593..1eb78d9669 100644
--- a/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
+++ b/Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs
@@ -176,7 +176,7 @@ private QueryTask CreateQueryTask()
 
       var session = manager.Owner.Session;
       var scope = new CompiledQueryProcessingScope(null, null, parameterContext, false);
-      QueryProvider = session.StorageNode.EntitySetFetchQueryCache .GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
+      QueryProvider = session.StorageNode.EntitySetFetchQueryCache.GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
       ExecutableProvider executableProvider;
       using (scope.Enter()) {
         executableProvider = session.Compile(QueryProvider);