public CommonTableBinding DeclareCommonTableExpression(Identifier identifier, QueryNode anchorMember) { CommonTableBinding derivedTableBinding = new CommonTableBinding(identifier.Text, anchorMember); _commonTables.Add(derivedTableBinding); return(derivedTableBinding); }
private static ResultAlgebraNode Convert(CommonTableBinding currentCommonTableBinding, QueryNode queryNode) { Algebrizer algebrizer = new Algebrizer(currentCommonTableBinding); AlgebraNode result = algebrizer.ConvertAstNode(queryNode); result = new SubqueryExpander().VisitAlgebraNode(result); return (ResultAlgebraNode)result; }
private static ResultAlgebraNode Convert(CommonTableBinding currentCommonTableBinding, QueryNode queryNode) { Algebrizer algebrizer = new Algebrizer(currentCommonTableBinding); AlgebraNode result = algebrizer.ConvertAstNode(queryNode); result = new SubqueryExpander().VisitAlgebraNode(result); return((ResultAlgebraNode)result); }
public override TableReference VisitNamedTableReference(NamedTableReference node) { CommonTableBinding tableBindingAsCommonTable = node.TableRefBinding.TableBinding as CommonTableBinding; if (tableBindingAsCommonTable == null) { // It is a regular table reference. Emit just a table node. List <ColumnValueDefinition> definedValues = new List <ColumnValueDefinition>(); foreach (ColumnRefBinding columnRefBinding in node.TableRefBinding.ColumnRefs) { definedValues.Add(columnRefBinding.ValueDefinition); } TableAlgebraNode algebraNode = new TableAlgebraNode(); algebraNode.TableRefBinding = node.TableRefBinding; algebraNode.DefinedValues = definedValues.ToArray(); SetLastAlgebraNode(algebraNode); } else { // It is a reference to a CTE. Instead of emitting a table node we have to replace the // reference to the CTE by the algebrized representation of the CTE. One could speak // of "inlining" the CTE. if (tableBindingAsCommonTable == _currentCommonTableBinding) { // This should never happen. The JoinAlgebraNode should ignore these table references. Debug.Fail("The current common table binding should never be reached as a table reference."); } AlgebraNode algebrizedCte; if (tableBindingAsCommonTable.IsRecursive) { algebrizedCte = AlgebrizeRecursiveCte(tableBindingAsCommonTable); } else { algebrizedCte = Convert(tableBindingAsCommonTable.AnchorMember); } // In order to use the CTE we have to instantiate it. See commonets in InstantiateCte() for // details. AlgebraNode computeScalarAlgebraNode = InstantiateCte(algebrizedCte, tableBindingAsCommonTable, node.TableRefBinding); SetLastAlgebraNode(computeScalarAlgebraNode); } return(node); }
private static AlgebraNode InstantiateCte(AlgebraNode algebrizedCte, CommonTableBinding commonTableBinding, TableRefBinding commonTableRefBinding) { // Replace row buffers to base tables by new ones. This must be done because a CTE could be referenced multiple times. // Since same row buffer entries means that the underlying data will be stored in the same physical data slot this // will lead to problems if, for example, two instances of the same CTE are joined together. Any join condition that // operates on the same column will always compare data coming from the same join side (and therefor will always // evaluate to true). // // Some notes on the implementation: // // 1. Note that just replacing references to row buffers of base tables in RowBufferExpression is not enough; // instead they must also be replaced in output lists, defined value references (esp. ConcatAlgebraNode) etc. // 2. Also note that although the QueryNodes are re-algebrized every time a CTE is references the expressions // are still copied from the QueryNodes (instead of cloned). Therefore two algrebrized CTEs will share the same // expression AST instances. That means that replacing the row buffers leads to failure. // HACK: This is a workaround for issue 2. However, // I am not quite sure how one should implement row buffer entry replacement without cloning the algebrized query. algebrizedCte = (AlgebraNode)algebrizedCte.Clone(); CteTableDefinedValuesReinitializer cteTableDefinedValuesReinitializer = new CteTableDefinedValuesReinitializer(); cteTableDefinedValuesReinitializer.Visit(algebrizedCte); RowBufferEntry[] outputList = algebrizedCte.OutputList; int skipRecursionLevel = commonTableBinding.IsRecursive ? 1 : 0; // Rename the query columns to the CTE columns List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>(); for (int i = 0; i < commonTableRefBinding.ColumnRefs.Length; i++) { RowBufferEntry targetRowBufferEntry = commonTableRefBinding.ColumnRefs[i].ValueDefinition.Target; RowBufferEntry sourceRowBufferEntry = outputList[i + skipRecursionLevel]; ComputedValueDefinition definedValue = new ComputedValueDefinition(); definedValue.Target = targetRowBufferEntry; definedValue.Expression = new RowBufferEntryExpression(sourceRowBufferEntry); definedValues.Add(definedValue); } ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = algebrizedCte; computeScalarAlgebraNode.DefinedValues = definedValues.ToArray(); return(computeScalarAlgebraNode); }
private static AlgebraNode AlgebrizeRecursiveCte(CommonTableBinding commonTableBinding) { // It is a recursive query. // // Create row buffer entry that is used to guard the recursion and the primary table spool // that spools the results needed by nested recursion calls. ExpressionBuilder expressionBuilder = new ExpressionBuilder(); StackedTableSpoolAlgebraNode primaryTableSpool = new StackedTableSpoolAlgebraNode(); RowBufferEntry anchorRecursionLevel; RowBufferEntry[] anchorOutput; AlgebraNode anchorNode; #region Anchor member { // Emit anchor member. AlgebraNode algebrizedAnchor = Convert(commonTableBinding.AnchorMember); // Emit compute scalar that initializes the recursion level to 0. anchorRecursionLevel = new RowBufferEntry(typeof(int)); ComputedValueDefinition computedValueDefinition1 = new ComputedValueDefinition(); computedValueDefinition1.Target = anchorRecursionLevel; computedValueDefinition1.Expression = LiteralExpression.FromInt32(0); ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = algebrizedAnchor; computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { computedValueDefinition1 }; anchorOutput = algebrizedAnchor.OutputList; anchorNode = computeScalarAlgebraNode; } #endregion RowBufferEntry incrementedRecursionLevel; RowBufferEntry[] tableSpoolOutput; AlgebraNode tableSpoolNode; #region Table spool { // Emit table spool reference. RowBufferEntry recursionLevelRefEntry = new RowBufferEntry(typeof(int)); tableSpoolOutput = new RowBufferEntry[anchorOutput.Length]; for (int i = 0; i < tableSpoolOutput.Length; i++) { tableSpoolOutput[i] = new RowBufferEntry(anchorOutput[i].DataType); } StackedTableSpoolRefAlgebraNode tableSpoolReference = new StackedTableSpoolRefAlgebraNode(); tableSpoolReference.PrimarySpool = primaryTableSpool; tableSpoolReference.DefinedValues = ArrayHelpers.JoinArrays(new RowBufferEntry[] { recursionLevelRefEntry }, tableSpoolOutput); // Emit compute scalar that increases the recursion level by one and renames // columns from the spool to the CTE column buffer entries. expressionBuilder.Push(new RowBufferEntryExpression(recursionLevelRefEntry)); expressionBuilder.Push(LiteralExpression.FromInt32(1)); expressionBuilder.PushBinary(BinaryOperator.Add); incrementedRecursionLevel = new RowBufferEntry(typeof(int)); ComputedValueDefinition incremenedRecLevelValueDefinition = new ComputedValueDefinition(); incremenedRecLevelValueDefinition.Target = incrementedRecursionLevel; incremenedRecLevelValueDefinition.Expression = expressionBuilder.Pop(); CteColumnMappingFinder cteColumnMappingFinder = new CteColumnMappingFinder(commonTableBinding, tableSpoolOutput); foreach (QueryNode recursiveMember in commonTableBinding.RecursiveMembers) { cteColumnMappingFinder.Visit(recursiveMember); } CteColumnMapping[] cteColumnMappings = cteColumnMappingFinder.GetMappings(); List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>(); definedValues.Add(incremenedRecLevelValueDefinition); foreach (CteColumnMapping cteColumnMapping in cteColumnMappings) { ComputedValueDefinition definedValue = new ComputedValueDefinition(); definedValue.Target = cteColumnMapping.VirtualBufferEntry; definedValue.Expression = new RowBufferEntryExpression(cteColumnMapping.SpoolBufferEntry); definedValues.Add(definedValue); } ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = tableSpoolReference; computeScalarAlgebraNode.DefinedValues = definedValues.ToArray(); tableSpoolNode = computeScalarAlgebraNode; } #endregion RowBufferEntry[] recursiveOutput; AlgebraNode recursiveNode; #region Recursive member(s) { // Emit all recursive parts. The join conditions to the recursive part are replaced by simple filters // in the nested Convert() call. ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode(); concatAlgebraNode.Inputs = new AlgebraNode[commonTableBinding.RecursiveMembers.Length]; for (int i = 0; i < commonTableBinding.RecursiveMembers.Length; i++) { concatAlgebraNode.Inputs[i] = Convert(commonTableBinding, commonTableBinding.RecursiveMembers[i]); } concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length]; for (int i = 0; i < anchorOutput.Length; i++) { List <RowBufferEntry> dependencies = new List <RowBufferEntry>(); foreach (ResultAlgebraNode algebrizedRecursivePart in concatAlgebraNode.Inputs) { dependencies.Add(algebrizedRecursivePart.OutputList[i]); } concatAlgebraNode.DefinedValues[i] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[i].Target = new RowBufferEntry(anchorOutput[i].DataType); concatAlgebraNode.DefinedValues[i].DependendEntries = dependencies.ToArray(); } // Calculate the recursive output. recursiveOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length]; for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++) { recursiveOutput[i] = concatAlgebraNode.DefinedValues[i].Target; } // Emit cross join JoinAlgebraNode crossJoinNode = new JoinAlgebraNode(); crossJoinNode.Left = tableSpoolNode; crossJoinNode.Right = concatAlgebraNode; // Emit assert that ensures that the recursion level is <= 100. expressionBuilder.Push(new RowBufferEntryExpression(incrementedRecursionLevel)); expressionBuilder.Push(LiteralExpression.FromInt32(100)); expressionBuilder.PushBinary(BinaryOperator.Greater); CaseExpression caseExpression = new CaseExpression(); caseExpression.WhenExpressions = new ExpressionNode[1]; caseExpression.WhenExpressions[0] = expressionBuilder.Pop(); caseExpression.ThenExpressions = new ExpressionNode[1]; caseExpression.ThenExpressions[0] = LiteralExpression.FromInt32(0); AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode(); assertAlgebraNode.Input = crossJoinNode; assertAlgebraNode.AssertionType = AssertionType.BelowRecursionLimit; assertAlgebraNode.Predicate = caseExpression; recursiveNode = assertAlgebraNode; } #endregion RowBufferEntry[] algebrizedOutput; AlgebraNode algebrizedCte; #region Combination { // Create concat node to combine anchor and recursive part. ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode(); concatAlgebraNode.Inputs = new AlgebraNode[2]; concatAlgebraNode.Inputs[0] = anchorNode; concatAlgebraNode.Inputs[1] = recursiveNode; concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length + 1]; concatAlgebraNode.DefinedValues[0] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[0].Target = new RowBufferEntry(anchorRecursionLevel.DataType); concatAlgebraNode.DefinedValues[0].DependendEntries = new RowBufferEntry[] { anchorRecursionLevel, incrementedRecursionLevel }; for (int i = 0; i < anchorOutput.Length; i++) { concatAlgebraNode.DefinedValues[i + 1] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[i + 1].Target = new RowBufferEntry(anchorOutput[i].DataType); concatAlgebraNode.DefinedValues[i + 1].DependendEntries = new RowBufferEntry[] { anchorOutput[i], recursiveOutput[i] }; } algebrizedOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length]; for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++) { algebrizedOutput[i] = concatAlgebraNode.DefinedValues[i].Target; } // Assign the combination as the input to the primray spool primaryTableSpool.Input = concatAlgebraNode; // The primary spool represents the result of the "inlined" CTE. algebrizedCte = primaryTableSpool; } #endregion algebrizedCte.OutputList = algebrizedOutput; return(algebrizedCte); }
private Algebrizer(CommonTableBinding currentCommonTableBinding) { _currentCommonTableBinding = currentCommonTableBinding; }
public CteColumnMappingFinder(CommonTableBinding commonTableBinding, RowBufferEntry[] spoolBufferEntries) { _commonTableBinding = commonTableBinding; _spoolBufferEntries = spoolBufferEntries; }
private static AlgebraNode InstantiateCte(AlgebraNode algebrizedCte, CommonTableBinding commonTableBinding, TableRefBinding commonTableRefBinding) { // Replace row buffers to base tables by new ones. This must be done because a CTE could be referenced multiple times. // Since same row buffer entries means that the underlying data will be stored in the same physical data slot this // will lead to problems if, for example, two instances of the same CTE are joined together. Any join condition that // operates on the same column will always compare data coming from the same join side (and therefor will always // evaluate to true). // // Some notes on the implementation: // // 1. Note that just replacing references to row buffers of base tables in RowBufferExpression is not enough; // instead they must also be replaced in output lists, defined value references (esp. ConcatAlgebraNode) etc. // 2. Also note that although the QueryNodes are re-algebrized every time a CTE is references the expressions // are still copied from the QueryNodes (instead of cloned). Therefore two algrebrized CTEs will share the same // expression AST instances. That means that replacing the row buffers leads to failure. // HACK: This is a workaround for issue 2. However, // I am not quite sure how one should implement row buffer entry replacement without cloning the algebrized query. algebrizedCte = (AlgebraNode) algebrizedCte.Clone(); CteTableDefinedValuesReinitializer cteTableDefinedValuesReinitializer = new CteTableDefinedValuesReinitializer(); cteTableDefinedValuesReinitializer.Visit(algebrizedCte); RowBufferEntry[] outputList = algebrizedCte.OutputList; int skipRecursionLevel = commonTableBinding.IsRecursive ? 1 : 0; // Rename the query columns to the CTE columns List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>(); for (int i = 0; i < commonTableRefBinding.ColumnRefs.Length; i++) { RowBufferEntry targetRowBufferEntry = commonTableRefBinding.ColumnRefs[i].ValueDefinition.Target; RowBufferEntry sourceRowBufferEntry = outputList[i + skipRecursionLevel]; ComputedValueDefinition definedValue = new ComputedValueDefinition(); definedValue.Target = targetRowBufferEntry; definedValue.Expression = new RowBufferEntryExpression(sourceRowBufferEntry); definedValues.Add(definedValue); } ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = algebrizedCte; computeScalarAlgebraNode.DefinedValues = definedValues.ToArray(); return computeScalarAlgebraNode; }
private static AlgebraNode AlgebrizeRecursiveCte(CommonTableBinding commonTableBinding) { // It is a recursive query. // // Create row buffer entry that is used to guard the recursion and the primary table spool // that spools the results needed by nested recursion calls. ExpressionBuilder expressionBuilder = new ExpressionBuilder(); StackedTableSpoolAlgebraNode primaryTableSpool = new StackedTableSpoolAlgebraNode(); RowBufferEntry anchorRecursionLevel; RowBufferEntry[] anchorOutput; AlgebraNode anchorNode; #region Anchor member { // Emit anchor member. AlgebraNode algebrizedAnchor = Convert(commonTableBinding.AnchorMember); // Emit compute scalar that initializes the recursion level to 0. anchorRecursionLevel = new RowBufferEntry(typeof(int)); ComputedValueDefinition computedValueDefinition1 = new ComputedValueDefinition(); computedValueDefinition1.Target = anchorRecursionLevel; computedValueDefinition1.Expression = LiteralExpression.FromInt32(0); ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = algebrizedAnchor; computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { computedValueDefinition1 }; anchorOutput = algebrizedAnchor.OutputList; anchorNode = computeScalarAlgebraNode; } #endregion RowBufferEntry incrementedRecursionLevel; RowBufferEntry[] tableSpoolOutput; AlgebraNode tableSpoolNode; #region Table spool { // Emit table spool reference. RowBufferEntry recursionLevelRefEntry = new RowBufferEntry(typeof(int)); tableSpoolOutput = new RowBufferEntry[anchorOutput.Length]; for (int i = 0; i < tableSpoolOutput.Length; i++) tableSpoolOutput[i] = new RowBufferEntry(anchorOutput[i].DataType); StackedTableSpoolRefAlgebraNode tableSpoolReference = new StackedTableSpoolRefAlgebraNode(); tableSpoolReference.PrimarySpool = primaryTableSpool; tableSpoolReference.DefinedValues = ArrayHelpers.JoinArrays(new RowBufferEntry[] { recursionLevelRefEntry }, tableSpoolOutput); // Emit compute scalar that increases the recursion level by one and renames // columns from the spool to the CTE column buffer entries. expressionBuilder.Push(new RowBufferEntryExpression(recursionLevelRefEntry)); expressionBuilder.Push(LiteralExpression.FromInt32(1)); expressionBuilder.PushBinary(BinaryOperator.Add); incrementedRecursionLevel = new RowBufferEntry(typeof(int)); ComputedValueDefinition incremenedRecLevelValueDefinition = new ComputedValueDefinition(); incremenedRecLevelValueDefinition.Target = incrementedRecursionLevel; incremenedRecLevelValueDefinition.Expression = expressionBuilder.Pop(); CteColumnMappingFinder cteColumnMappingFinder = new CteColumnMappingFinder(commonTableBinding, tableSpoolOutput); foreach (QueryNode recursiveMember in commonTableBinding.RecursiveMembers) cteColumnMappingFinder.Visit(recursiveMember); CteColumnMapping[] cteColumnMappings = cteColumnMappingFinder.GetMappings(); List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>(); definedValues.Add(incremenedRecLevelValueDefinition); foreach (CteColumnMapping cteColumnMapping in cteColumnMappings) { ComputedValueDefinition definedValue = new ComputedValueDefinition(); definedValue.Target = cteColumnMapping.VirtualBufferEntry; definedValue.Expression = new RowBufferEntryExpression(cteColumnMapping.SpoolBufferEntry); definedValues.Add(definedValue); } ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode(); computeScalarAlgebraNode.Input = tableSpoolReference; computeScalarAlgebraNode.DefinedValues = definedValues.ToArray(); tableSpoolNode = computeScalarAlgebraNode; } #endregion RowBufferEntry[] recursiveOutput; AlgebraNode recursiveNode; #region Recursive member(s) { // Emit all recursive parts. The join conditions to the recursive part are replaced by simple filters // in the nested Convert() call. ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode(); concatAlgebraNode.Inputs = new AlgebraNode[commonTableBinding.RecursiveMembers.Length]; for (int i = 0; i < commonTableBinding.RecursiveMembers.Length; i++) concatAlgebraNode.Inputs[i] = Convert(commonTableBinding, commonTableBinding.RecursiveMembers[i]); concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length]; for (int i = 0; i < anchorOutput.Length; i++) { List<RowBufferEntry> dependencies = new List<RowBufferEntry>(); foreach (ResultAlgebraNode algebrizedRecursivePart in concatAlgebraNode.Inputs) dependencies.Add(algebrizedRecursivePart.OutputList[i]); concatAlgebraNode.DefinedValues[i] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[i].Target = new RowBufferEntry(anchorOutput[i].DataType); concatAlgebraNode.DefinedValues[i].DependendEntries = dependencies.ToArray(); } // Calculate the recursive output. recursiveOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length]; for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++) recursiveOutput[i] = concatAlgebraNode.DefinedValues[i].Target; // Emit cross join JoinAlgebraNode crossJoinNode = new JoinAlgebraNode(); crossJoinNode.Left = tableSpoolNode; crossJoinNode.Right = concatAlgebraNode; // Emit assert that ensures that the recursion level is <= 100. expressionBuilder.Push(new RowBufferEntryExpression(incrementedRecursionLevel)); expressionBuilder.Push(LiteralExpression.FromInt32(100)); expressionBuilder.PushBinary(BinaryOperator.Greater); CaseExpression caseExpression = new CaseExpression(); caseExpression.WhenExpressions = new ExpressionNode[1]; caseExpression.WhenExpressions[0] = expressionBuilder.Pop(); caseExpression.ThenExpressions = new ExpressionNode[1]; caseExpression.ThenExpressions[0] = LiteralExpression.FromInt32(0); AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode(); assertAlgebraNode.Input = crossJoinNode; assertAlgebraNode.AssertionType = AssertionType.BelowRecursionLimit; assertAlgebraNode.Predicate = caseExpression; recursiveNode = assertAlgebraNode; } #endregion RowBufferEntry[] algebrizedOutput; AlgebraNode algebrizedCte; #region Combination { // Create concat node to combine anchor and recursive part. ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode(); concatAlgebraNode.Inputs = new AlgebraNode[2]; concatAlgebraNode.Inputs[0] = anchorNode; concatAlgebraNode.Inputs[1] = recursiveNode; concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length + 1]; concatAlgebraNode.DefinedValues[0] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[0].Target = new RowBufferEntry(anchorRecursionLevel.DataType); concatAlgebraNode.DefinedValues[0].DependendEntries = new RowBufferEntry[] { anchorRecursionLevel, incrementedRecursionLevel }; for (int i = 0; i < anchorOutput.Length; i++) { concatAlgebraNode.DefinedValues[i + 1] = new UnitedValueDefinition(); concatAlgebraNode.DefinedValues[i + 1].Target = new RowBufferEntry(anchorOutput[i].DataType); concatAlgebraNode.DefinedValues[i + 1].DependendEntries = new RowBufferEntry[] { anchorOutput[i], recursiveOutput[i] }; } algebrizedOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length]; for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++) algebrizedOutput[i] = concatAlgebraNode.DefinedValues[i].Target; // Assign the combination as the input to the primray spool primaryTableSpool.Input = concatAlgebraNode; // The primary spool represents the result of the "inlined" CTE. algebrizedCte = primaryTableSpool; } #endregion algebrizedCte.OutputList = algebrizedOutput; return algebrizedCte; }