Rename internal cache names, add comments

Author: SergeiPavlov

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();
     }

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)

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);
     }

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);

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);

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>();