Query: Remove TpcTablesExpression once pruning is done (#28142)

- Apply pruning on subqueries in set operation when not distinct - Avoid table aliases which would be pruned in TPC later - Avoid push down when left-joining with TPC select expression Resolves npgsql/efcore.pg#2387 Resolves #28009
dotnet · Jun 2, 2022 · f43f454 · f43f454
1 parent 7433fe6
commit f43f454
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Showing 22 changed files with 1,917 additions and 1,946 deletions.
diff --git a/src/EFCore.Relational/Query/EntityProjectionExpression.cs b/src/EFCore.Relational/Query/EntityProjectionExpression.cs
@@ -123,7 +123,7 @@ public virtual EntityProjectionExpression UpdateEntityType(IEntityType derivedTy
         var discriminatorExpression = DiscriminatorExpression;
         if (DiscriminatorExpression is CaseExpression caseExpression)
         {
-            var entityTypesToSelect = derivedType.GetConcreteDerivedTypesInclusive().Select(e => e.GetDiscriminatorValue()).ToList();
+            var entityTypesToSelect = derivedType.GetConcreteDerivedTypesInclusive().Select(e => (string)e.GetDiscriminatorValue()!).ToList();
             var whenClauses = caseExpression.WhenClauses
                 .Where(wc => entityTypesToSelect.Contains((string)((SqlConstantExpression)wc.Result).Value!))
                 .ToList();

diff --git a/src/EFCore.Relational/Query/Internal/TpcTablesExpression.cs b/src/EFCore.Relational/Query/Internal/TpcTablesExpression.cs
diff --git a/src/EFCore.Relational/Query/QuerySqlGenerator.cs b/src/EFCore.Relational/Query/QuerySqlGenerator.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using Microsoft.EntityFrameworkCore.Query.Internal;
 using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 using Microsoft.EntityFrameworkCore.Storage.Internal;
 
@@ -148,141 +147,77 @@ private static bool IsNonComposedSetOperation(SelectExpression selectExpression)
                             column.Name, setOperation.Source1.Projection[index].Alias, StringComparison.Ordinal))
                 .All(e => e);
 
-    private static bool IsNonComposedTpc(SelectExpression selectExpression)
-        => selectExpression.Offset == null
-            && selectExpression.Limit == null
-            && !selectExpression.IsDistinct
-            && selectExpression.Predicate == null
-            && selectExpression.Having == null
-            && selectExpression.Orderings.Count == 0
-            && selectExpression.GroupBy.Count == 0
-            && selectExpression.Tables.Count == 1
-            && selectExpression.Tables[0] is TpcTablesExpression tpcTablesExpression
-            && selectExpression.Projection.Count == tpcTablesExpression.SelectExpressions[0].Projection.Count
-            && selectExpression.Projection.Select(
-                    (pe, index) => pe.Expression is ColumnExpression column
-                        && string.Equals(column.TableAlias, tpcTablesExpression.Alias, StringComparison.Ordinal)
-                        && string.Equals(
-                            column.Name, tpcTablesExpression.SelectExpressions[0].Projection[index].Alias, StringComparison.Ordinal))
-                .All(e => e);
-
     /// <inheritdoc />
-    protected override Expression VisitExtension(Expression extensionExpression)
+    protected override Expression VisitSelect(SelectExpression selectExpression)
     {
-        if (extensionExpression is TpcTablesExpression tpcTablesExpression)
+        IDisposable? subQueryIndent = null;
+        if (selectExpression.Alias != null)
         {
             _relationalCommandBuilder.AppendLine("(");
-            using (_relationalCommandBuilder.Indent())
-            {
-                GenerateList(tpcTablesExpression.SelectExpressions, e => Visit(e), e => e.AppendLine().AppendLine("UNION ALL"));
-            }
-            _relationalCommandBuilder.AppendLine()
-                .Append(")")
-                .Append(AliasSeparator)
-                .Append(_sqlGenerationHelper.DelimitIdentifier(tpcTablesExpression.Alias));
-
-            return tpcTablesExpression;
+            subQueryIndent = _relationalCommandBuilder.Indent();
         }
 
-        return base.VisitExtension(extensionExpression);
-    }
-
-    /// <inheritdoc />
-    protected override Expression VisitSelect(SelectExpression selectExpression)
-    {
         if (IsNonComposedSetOperation(selectExpression))
         {
             // Naked set operation
             GenerateSetOperation((SetOperationBase)selectExpression.Tables[0]);
-
-            return selectExpression;
         }
-
-        IDisposable? subQueryIndent = null;
-
-        if (IsNonComposedTpc(selectExpression))
+        else
         {
-            var tpcTablesExpression = (TpcTablesExpression)selectExpression.Tables[0];
-            if (selectExpression.Alias != null)
+            _relationalCommandBuilder.Append("SELECT ");
+
+            if (selectExpression.IsDistinct)
             {
-                _relationalCommandBuilder.AppendLine("(");
-                subQueryIndent = _relationalCommandBuilder.Indent();
+                _relationalCommandBuilder.Append("DISTINCT ");
             }
 
-            GenerateList(tpcTablesExpression.SelectExpressions, e => Visit(e), e => e.AppendLine().AppendLine("UNION ALL"));
+            GenerateTop(selectExpression);
 
-            if (selectExpression.Alias != null)
+            if (selectExpression.Projection.Any())
             {
-                subQueryIndent!.Dispose();
-
-                _relationalCommandBuilder.AppendLine()
-                    .Append(")")
-                    .Append(AliasSeparator)
-                    .Append(_sqlGenerationHelper.DelimitIdentifier(selectExpression.Alias));
+                GenerateList(selectExpression.Projection, e => Visit(e));
+            }
+            else
+            {
+                _relationalCommandBuilder.Append("1");
             }
 
-            return selectExpression;
-        }
-
-        if (selectExpression.Alias != null)
-        {
-            _relationalCommandBuilder.AppendLine("(");
-            subQueryIndent = _relationalCommandBuilder.Indent();
-        }
-
-        _relationalCommandBuilder.Append("SELECT ");
-
-        if (selectExpression.IsDistinct)
-        {
-            _relationalCommandBuilder.Append("DISTINCT ");
-        }
-
-        GenerateTop(selectExpression);
-
-        if (selectExpression.Projection.Any())
-        {
-            GenerateList(selectExpression.Projection, e => Visit(e));
-        }
-        else
-        {
-            _relationalCommandBuilder.Append("1");
-        }
+            if (selectExpression.Tables.Any())
+            {
+                _relationalCommandBuilder.AppendLine().Append("FROM ");
 
-        if (selectExpression.Tables.Any())
-        {
-            _relationalCommandBuilder.AppendLine().Append("FROM ");
+                GenerateList(selectExpression.Tables, e => Visit(e), sql => sql.AppendLine());
+            }
+            else
+            {
+                GeneratePseudoFromClause();
+            }
 
-            GenerateList(selectExpression.Tables, e => Visit(e), sql => sql.AppendLine());
-        }
-        else
-        {
-            GeneratePseudoFromClause();
-        }
+            if (selectExpression.Predicate != null)
+            {
+                _relationalCommandBuilder.AppendLine().Append("WHERE ");
 
-        if (selectExpression.Predicate != null)
-        {
-            _relationalCommandBuilder.AppendLine().Append("WHERE ");
+                Visit(selectExpression.Predicate);
+            }
 
-            Visit(selectExpression.Predicate);
-        }
+            if (selectExpression.GroupBy.Count > 0)
+            {
+                _relationalCommandBuilder.AppendLine().Append("GROUP BY ");
 
-        if (selectExpression.GroupBy.Count > 0)
-        {
-            _relationalCommandBuilder.AppendLine().Append("GROUP BY ");
+                GenerateList(selectExpression.GroupBy, e => Visit(e));
+            }
 
-            GenerateList(selectExpression.GroupBy, e => Visit(e));
-        }
+            if (selectExpression.Having != null)
+            {
+                _relationalCommandBuilder.AppendLine().Append("HAVING ");
 
-        if (selectExpression.Having != null)
-        {
-            _relationalCommandBuilder.AppendLine().Append("HAVING ");
+                Visit(selectExpression.Having);
+            }
 
-            Visit(selectExpression.Having);
+            GenerateOrderings(selectExpression);
+            GenerateLimitOffset(selectExpression);
         }
 
-        GenerateOrderings(selectExpression);
-        GenerateLimitOffset(selectExpression);
-
         if (selectExpression.Alias != null)
         {
             subQueryIndent!.Dispose();