PostgreSQL:Add support for CrossApply feature for v10 and newer

Since 9.3 there is native support for cross apply and outer apply.
This is improve queries with apply significantly.

Author: alex-kulakov

Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/ServerInfoProvider.cs

@@ -1,13 +1,22 @@
-// Copyright (C) 2019-2020 Xtensive LLC.
+// Copyright (C) 2019-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Alexey Kulakov
 // Created:    2019.09.25
 
+using Xtensive.Sql.Info;
+
 namespace Xtensive.Sql.Drivers.PostgreSql.v10_0
 {
   internal class ServerInfoProvider : v9_0.ServerInfoProvider
   {
+    public override QueryInfo GetQueryInfo()
+    {
+      var info = base.GetQueryInfo();
+      info.Features |= QueryFeatures.CrossApply;
+      return info;
+    }
+
     // Constructors
 
     public ServerInfoProvider(SqlDriver driver)

Orm/Xtensive.Orm.PostgreSql/Sql.Drivers.PostgreSql/v10_0/Translator.cs

@@ -1,13 +1,46 @@
-// Copyright (C) 2019-2020 Xtensive LLC.
+// Copyright (C) 2019-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Alexey Kulakov
 // Created:    2019.09.25
 
+using System;
+using Xtensive.Sql.Compiler;
+using Xtensive.Sql.Dml;
+
 namespace Xtensive.Sql.Drivers.PostgreSql.v10_0
 {
   internal class Translator : v9_1.Translator
   {
+    public override string Translate(SqlCompilerContext context, SqlJoinExpression node, JoinSection section)
+    {
+      switch (section) {
+        case JoinSection.Specification: {
+          if (node.Expression == null) {
+            switch (node.JoinType) {
+              case SqlJoinType.InnerJoin:
+              case SqlJoinType.LeftOuterJoin:
+              case SqlJoinType.RightOuterJoin:
+              case SqlJoinType.FullOuterJoin:
+                throw new NotSupportedException();
+              case SqlJoinType.CrossApply:
+                return "CROSS JOIN LATERAL";
+              case SqlJoinType.LeftOuterApply:
+                return "LEFT JOIN LATERAL";
+            }
+          }
+          return Translate(node.JoinType) + " JOIN";
+        }
+        case JoinSection.Exit: {
+          if (node.JoinType == SqlJoinType.LeftOuterApply) {
+            return "ON TRUE";
+          }
+          return string.Empty;
+        }
+      }
+      return base.Translate(context, node, section);
+    }
+
     // Constructors
 
     public Translator(SqlDriver driver)

Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Apply.cs

@@ -1,6 +1,6 @@
-// Copyright (C) 2003-2010 Xtensive LLC.
-// All rights reserved.
-// For conditions of distribution and use, see license.
+// 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
 // Created:    2009.11.13
 
@@ -17,7 +17,7 @@
 
 namespace Xtensive.Orm.Providers
 {
-  partial class SqlCompiler 
+  public partial class SqlCompiler
   {
     /// <inheritdoc/>
     protected override SqlProvider VisitApply(ApplyProvider provider)
@@ -170,15 +170,15 @@ private SqlSelect ProcessApplyViaCrossApply(ApplyProvider provider, SqlProvider
         ? (IReadOnlyList<SqlColumn>) leftTable.Columns
         : left.Request.Statement.Columns;
 
-      var rightShouldUseReference = ShouldUseQueryReference(provider, right);
+      var rightShouldUseReference = ShouldUseQueryReference(provider, right) || forceApplyViaReference;
       var rightTable = rightShouldUseReference
         ? right.PermanentReference
         : right.Request.Statement.From;
       var rightColumns = rightShouldUseReference
         ? (IReadOnlyList<SqlColumn>) rightTable.Columns
         : right.Request.Statement.Columns;
 
-      var joinType = provider.ApplyType==JoinType.LeftOuter
+      var joinType = provider.ApplyType == JoinType.LeftOuter
         ? SqlJoinType.LeftOuterApply
         : SqlJoinType.CrossApply;
 

Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.cs

@@ -1,6 +1,6 @@
-// Copyright (C) 2003-2010 Xtensive LLC.
-// All rights reserved.
-// For conditions of distribution and use, see license.
+// 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: Vakhtina Elena
 // Created:    2009.02.13
 
@@ -28,6 +28,7 @@ public partial class SqlCompiler : Compiler<SqlProvider>
     private readonly ProviderInfo providerInfo;
     private readonly bool temporaryTablesSupported;
     private readonly HashSet<Column> rootColumns = new HashSet<Column>();
+    private readonly bool forceApplyViaReference;
 
     private bool anyTemporaryTablesRequired;
 
@@ -562,6 +563,7 @@ public SqlCompiler(HandlerAccessor handlers, CompilerConfiguration configuration
 
       providerInfo = Handlers.ProviderInfo;
       temporaryTablesSupported = DomainHandler.TemporaryTableManager.Supported;
+      forceApplyViaReference = handlers.ProviderInfo.ProviderName.Equals(WellKnown.Provider.PostgreSql);
 
       if (!providerInfo.Supports(ProviderFeatures.FullFeaturedBooleanExpressions))
         booleanExpressionConverter = new BooleanExpressionConverter(Driver);