Make EntitySetFetchQueryCache static

Author: SergeiPavlov

Orm/Xtensive.Orm/Orm/Internals/Prefetch/EntitySetTask.cs

@@ -4,11 +4,6 @@
 // Created by: Alexander Nikolaev
 // Created:    2009.09.09
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Linq.Expressions;
-using System.Reflection;
 using Xtensive.Core;
 using Xtensive.Orm.Linq;
 using Xtensive.Orm.Model;
@@ -173,7 +168,7 @@ private QueryTask CreateQueryTask()
 
       var session = manager.Owner.Session;
       var scope = new CompiledQueryProcessingScope(null, null, parameterContext, false);
-      QueryProvider = session.StorageNode.EntitySetFetchQueryCache.GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
+      QueryProvider = StorageNode.EntitySetFetchQueryCache.GetOrAdd(cacheKey, CreateRecordSetLoadingItems);
       if (session.Domain.TagsEnabled && session.Tags != null) {
         foreach (var tag in session.Tags) {
           QueryProvider = new TagProvider(QueryProvider, tag);

Orm/Xtensive.Orm/Orm/StorageNode.cs

@@ -61,7 +61,7 @@ public sealed class StorageNode : ISessionSource
     /// <summary>
     /// Caches uncompiled queries used by <see cref="PrefetchManager"/> to fetch <see cref="EntitySet{TItem}"/> content.
     /// </summary>
-    internal ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> EntitySetFetchQueryCache { get; } = new();
+    internal static ConcurrentDictionary<ItemsQueryCacheKey, CompilableProvider> EntitySetFetchQueryCache { get; } = new();
 
     /// <summary>
     /// Caches certain info about EntitySet fields, e.g. queries to fetch current count or items.