public override TableReference VisitDerivedTableReference(DerivedTableReference node)
{
AlgebraNode algebrizedQuery = Convert(node.Query);
List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>();
for (int i = 0; i < node.DerivedTableBinding.ColumnRefs.Length; i++)
{
RowBufferEntry targetRowBufferEntry = node.DerivedTableBinding.ColumnRefs[i].ValueDefinition.Target;
RowBufferEntry sourceRowBufferEntry = algebrizedQuery.OutputList[i];
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = targetRowBufferEntry;
definedValue.Expression = new RowBufferEntryExpression(sourceRowBufferEntry);
definedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = algebrizedQuery;
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
SetLastAlgebraNode(computeScalarAlgebraNode);
return(node);
}
private static void CreateBufferedValue(ExpressionNode expression, ICollection <ComputedValueDefinition> computedColumnList, ICollection <RowBufferEntry> columnList, IEnumerable <ComputedValueDefinition> alreadyComputedBufferedValues)
{
if (alreadyComputedBufferedValues != null)
{
expression = ReplaceAlreadyComputedSubsequences(expression, alreadyComputedBufferedValues);
}
foreach (ComputedValueDefinition computedBufferedValue in computedColumnList)
{
if (expression.IsStructuralEqualTo(computedBufferedValue.Expression))
{
columnList.Add(computedBufferedValue.Target);
return;
}
}
RowBufferEntryExpression rowBufferExpression = expression as RowBufferEntryExpression;
if (rowBufferExpression != null)
{
columnList.Add(rowBufferExpression.RowBufferEntry);
}
else
{
RowBufferEntry rowBufferEntry = new RowBufferEntry(expression.ExpressionType);
columnList.Add(rowBufferEntry);
ComputedValueDefinition computedValue = new ComputedValueDefinition();
computedValue.Target = rowBufferEntry;
computedValue.Expression = expression;
computedColumnList.Add(computedValue);
}
}
private static AlgebraNode PadLeftWithNullsOnRightSide(JoinAlgebraNode node, RowBufferCreationMode rowBufferCreationMode)
{
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = node.Left;
List<RowBufferEntry> outputList = new List<RowBufferEntry>();
outputList.AddRange(node.Left.OutputList);
List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>();
foreach (RowBufferEntry rowBufferEntry in node.Right.OutputList)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
if (rowBufferCreationMode == RowBufferCreationMode.KeepExisting)
{
definedValue.Target = rowBufferEntry;
}
else
{
definedValue.Target = new RowBufferEntry(rowBufferEntry.DataType);
}
definedValue.Expression = LiteralExpression.FromTypedNull(rowBufferEntry.DataType);
definedValues.Add(definedValue);
outputList.Add(definedValue.Target);
}
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
computeScalarAlgebraNode.OutputList = outputList.ToArray();
return computeScalarAlgebraNode;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
ExpressionNode originalPredicate = (ExpressionNode) node.Predicate.Clone();
SpoolExpressionExtractor spoolExpressionExtractor = new SpoolExpressionExtractor(_outerReferences);
// HACK: This hack ensures that TRUE literals introduced by SpoolExpressionExtractor are removed.
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, spoolExpressionExtractor.VisitExpression(node.Predicate));
SpoolExpression[] spoolExpressions = spoolExpressionExtractor.GetSpoolExpressions();
// Now we must check that the remaining filter incl. input to the filter don't reference any other
// outer reference.
bool remainingFilterHasDependenciesToOuterReferences = CheckIfNodeHasDependenciesToOuterReferences(node);
if (remainingFilterHasDependenciesToOuterReferences)
{
// OK; we cannot insert a spool operation here. Undo the expression replacement.
node.Predicate = originalPredicate;
}
else if (spoolExpressions.Length > 0)
{
SpoolExpression spoolExpression = spoolExpressions[0];
AlgebraNode currentInput;
if (node.Predicate is ConstantExpression)
currentInput = node.Input;
else
currentInput = node;
RowBufferEntry indexEntry;
RowBufferEntryExpression indexExpressionAsRowBufferEntryExpression = spoolExpression.IndexExpression as RowBufferEntryExpression;
if (indexExpressionAsRowBufferEntryExpression != null)
{
indexEntry = indexExpressionAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
indexEntry = new RowBufferEntry(spoolExpression.IndexExpression.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = indexEntry;
definedValue.Expression = spoolExpression.IndexExpression;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = currentInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { definedValue };
currentInput = computeScalarAlgebraNode;
}
IndexSpoolAlgebraNode indexSpoolAlgebraNode = new IndexSpoolAlgebraNode();
indexSpoolAlgebraNode.Input = currentInput;
indexSpoolAlgebraNode.IndexEntry = indexEntry;
indexSpoolAlgebraNode.ProbeExpression = spoolExpression.ProbeExpression;
return indexSpoolAlgebraNode;
}
return node;
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
base.VisitJoinAlgebraNode(node);
if (node.Op == JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
// TODO: Check if we could represent this join condition by an hash match operator
JoinAlgebraNode leftOuterJoinNode = new JoinAlgebraNode();
leftOuterJoinNode.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
leftOuterJoinNode.Predicate = (ExpressionNode)node.Predicate.Clone();
leftOuterJoinNode.Left = (AlgebraNode)node.Left.Clone();
leftOuterJoinNode.Right = (AlgebraNode)node.Right.Clone();
leftOuterJoinNode.OutputList = ArrayHelpers.Clone(node.OutputList);
List <RowBufferEntry> swappedOutputList = new List <RowBufferEntry>();
swappedOutputList.AddRange(node.Right.OutputList);
swappedOutputList.AddRange(node.Left.OutputList);
JoinAlgebraNode leftAntiSemiJoinNode = new JoinAlgebraNode();
leftAntiSemiJoinNode.Op = JoinAlgebraNode.JoinOperator.LeftAntiSemiJoin;
leftAntiSemiJoinNode.Predicate = (ExpressionNode)node.Predicate.Clone();
leftAntiSemiJoinNode.Left = (AlgebraNode)node.Right.Clone();
leftAntiSemiJoinNode.Right = (AlgebraNode)node.Left.Clone();
leftAntiSemiJoinNode.OutputList = swappedOutputList.ToArray();
List <ComputedValueDefinition> computeScalareDefinedValues = new List <ComputedValueDefinition>();
foreach (RowBufferEntry rowBufferEntry in node.Left.OutputList)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = rowBufferEntry;
definedValue.Expression = LiteralExpression.FromTypedNull(rowBufferEntry.DataType);
computeScalareDefinedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarNode = new ComputeScalarAlgebraNode();
computeScalarNode.Input = leftAntiSemiJoinNode;
computeScalarNode.DefinedValues = computeScalareDefinedValues.ToArray();
computeScalarNode.OutputList = swappedOutputList.ToArray();
List <UnitedValueDefinition> concatDefinedValues = new List <UnitedValueDefinition>();
for (int i = 0; i < node.OutputList.Length; i++)
{
RowBufferEntry rowBufferEntry = node.OutputList[i];
UnitedValueDefinition concatDefinedValue = new UnitedValueDefinition();
concatDefinedValue.Target = rowBufferEntry;
concatDefinedValue.DependendEntries = new RowBufferEntry[] { node.OutputList[i], node.OutputList[i] };
concatDefinedValues.Add(concatDefinedValue);
}
ConcatAlgebraNode concatenationNode = new ConcatAlgebraNode();
concatenationNode.Inputs = new AlgebraNode[] { leftOuterJoinNode, computeScalarNode };
concatenationNode.DefinedValues = concatDefinedValues.ToArray();
concatenationNode.OutputList = swappedOutputList.ToArray();
return(concatenationNode);
}
return(node);
}
private static AlgebraNode PadLeftWithNullsOnRightSide(JoinAlgebraNode node, RowBufferCreationMode rowBufferCreationMode)
{
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = node.Left;
List <RowBufferEntry> outputList = new List <RowBufferEntry>();
outputList.AddRange(node.Left.OutputList);
List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>();
foreach (RowBufferEntry rowBufferEntry in node.Right.OutputList)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
if (rowBufferCreationMode == RowBufferCreationMode.KeepExisting)
{
definedValue.Target = rowBufferEntry;
}
else
{
definedValue.Target = new RowBufferEntry(rowBufferEntry.DataType);
}
definedValue.Expression = LiteralExpression.FromTypedNull(rowBufferEntry.DataType);
definedValues.Add(definedValue);
outputList.Add(definedValue.Target);
}
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
computeScalarAlgebraNode.OutputList = outputList.ToArray();
return(computeScalarAlgebraNode);
}
public override AstElement Clone(Dictionary<AstElement, AstElement> alreadyClonedElements)
{
ComputedValueDefinition result = new ComputedValueDefinition();
result.Target = Target;
result.Expression = (ExpressionNode)_expression.Clone(alreadyClonedElements);
return result;
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
base.VisitJoinAlgebraNode(node);
if (node.Op == JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
// TODO: Check if we could represent this join condition by an hash match operator
JoinAlgebraNode leftOuterJoinNode = new JoinAlgebraNode();
leftOuterJoinNode.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
leftOuterJoinNode.Predicate = (ExpressionNode)node.Predicate.Clone();
leftOuterJoinNode.Left = (AlgebraNode) node.Left.Clone();
leftOuterJoinNode.Right = (AlgebraNode) node.Right.Clone();
leftOuterJoinNode.OutputList = ArrayHelpers.Clone(node.OutputList);
List<RowBufferEntry> swappedOutputList = new List<RowBufferEntry>();
swappedOutputList.AddRange(node.Right.OutputList);
swappedOutputList.AddRange(node.Left.OutputList);
JoinAlgebraNode leftAntiSemiJoinNode = new JoinAlgebraNode();
leftAntiSemiJoinNode.Op = JoinAlgebraNode.JoinOperator.LeftAntiSemiJoin;
leftAntiSemiJoinNode.Predicate = (ExpressionNode) node.Predicate.Clone();
leftAntiSemiJoinNode.Left = (AlgebraNode) node.Right.Clone();
leftAntiSemiJoinNode.Right = (AlgebraNode) node.Left.Clone();
leftAntiSemiJoinNode.OutputList = swappedOutputList.ToArray();
List<ComputedValueDefinition> computeScalareDefinedValues = new List<ComputedValueDefinition>();
foreach (RowBufferEntry rowBufferEntry in node.Left.OutputList)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = rowBufferEntry;
definedValue.Expression = LiteralExpression.FromTypedNull(rowBufferEntry.DataType);
computeScalareDefinedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarNode = new ComputeScalarAlgebraNode();
computeScalarNode.Input = leftAntiSemiJoinNode;
computeScalarNode.DefinedValues = computeScalareDefinedValues.ToArray();
computeScalarNode.OutputList = swappedOutputList.ToArray();
List<UnitedValueDefinition> concatDefinedValues = new List<UnitedValueDefinition>();
for (int i = 0; i < node.OutputList.Length; i++)
{
RowBufferEntry rowBufferEntry = node.OutputList[i];
UnitedValueDefinition concatDefinedValue = new UnitedValueDefinition();
concatDefinedValue.Target = rowBufferEntry;
concatDefinedValue.DependendEntries = new RowBufferEntry[] { node.OutputList[i], node.OutputList[i] };
concatDefinedValues.Add(concatDefinedValue);
}
ConcatAlgebraNode concatenationNode = new ConcatAlgebraNode();
concatenationNode.Inputs = new AlgebraNode[] {leftOuterJoinNode, computeScalarNode};
concatenationNode.DefinedValues = concatDefinedValues.ToArray();
concatenationNode.OutputList = swappedOutputList.ToArray();
return concatenationNode;
}
return node;
}
public override AstElement Clone(Dictionary <AstElement, AstElement> alreadyClonedElements)
{
ComputedValueDefinition result = new ComputedValueDefinition();
result.Target = Target;
result.Expression = (ExpressionNode)_expression.Clone(alreadyClonedElements);
return(result);
}
private void EmitComputeScalarIfNeeded(ComputedValueDefinition[] definedValues)
{
if (definedValues != null && definedValues.Length > 0)
{
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = GetLastAlgebraNode();
computeScalarAlgebraNode.DefinedValues = definedValues;
SetLastAlgebraNode(computeScalarAlgebraNode);
}
}
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);
}
public override AlgebraNode VisitAggregateAlgebraNode(AggregateAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
if (node.Input is NullScanAlgebraNode)
{
if (node.Groups != null && node.Groups.Length > 0)
{
// Grouped queries return nothing on empty input.
return(CreateNullScan(node.OutputList));
}
else
{
// Non-grouped aggregation. We return the result value of the aggregates
// executed against an empty input as a single row.
List <RowBufferEntry> outputList = new List <RowBufferEntry>();
List <ComputedValueDefinition> emptyValueList = new List <ComputedValueDefinition>();
foreach (AggregatedValueDefinition definedValue in node.DefinedValues)
{
IAggregator aggregator = definedValue.Aggregator;
aggregator.Init();
object emptyValue = aggregator.Terminate();
ComputedValueDefinition computedBufferedValue = new ComputedValueDefinition();
computedBufferedValue.Target = definedValue.Target;
computedBufferedValue.Expression = LiteralExpression.FromTypedValue(emptyValue, aggregator.ReturnType);
emptyValueList.Add(computedBufferedValue);
outputList.Add(computedBufferedValue.Target);
}
ConstantScanAlgebraNode constantScanAlgebraNode = new ConstantScanAlgebraNode();
constantScanAlgebraNode.DefinedValues = emptyValueList.ToArray();
constantScanAlgebraNode.OutputList = outputList.ToArray();
return(constantScanAlgebraNode);
}
}
return(node);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
ExpressionNode originalPredicate = (ExpressionNode)node.Predicate.Clone();
SpoolExpressionExtractor spoolExpressionExtractor = new SpoolExpressionExtractor(_outerReferences);
// HACK: This hack ensures that TRUE literals introduced by SpoolExpressionExtractor are removed.
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, spoolExpressionExtractor.VisitExpression(node.Predicate));
SpoolExpression[] spoolExpressions = spoolExpressionExtractor.GetSpoolExpressions();
// Now we must check that the remaining filter incl. input to the filter don't reference any other
// outer reference.
bool remainingFilterHasDependenciesToOuterReferences = CheckIfNodeHasDependenciesToOuterReferences(node);
if (remainingFilterHasDependenciesToOuterReferences)
{
// OK; we cannot insert a spool operation here. Undo the expression replacement.
node.Predicate = originalPredicate;
}
else if (spoolExpressions.Length > 0)
{
SpoolExpression spoolExpression = spoolExpressions[0];
AlgebraNode currentInput;
if (node.Predicate is ConstantExpression)
{
currentInput = node.Input;
}
else
{
currentInput = node;
}
RowBufferEntry indexEntry;
RowBufferEntryExpression indexExpressionAsRowBufferEntryExpression = spoolExpression.IndexExpression as RowBufferEntryExpression;
if (indexExpressionAsRowBufferEntryExpression != null)
{
indexEntry = indexExpressionAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
indexEntry = new RowBufferEntry(spoolExpression.IndexExpression.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = indexEntry;
definedValue.Expression = spoolExpression.IndexExpression;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = currentInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { definedValue };
currentInput = computeScalarAlgebraNode;
}
IndexSpoolAlgebraNode indexSpoolAlgebraNode = new IndexSpoolAlgebraNode();
indexSpoolAlgebraNode.Input = currentInput;
indexSpoolAlgebraNode.IndexEntry = indexEntry;
indexSpoolAlgebraNode.ProbeExpression = spoolExpression.ProbeExpression;
return(indexSpoolAlgebraNode);
}
return(node);
}
public override AlgebraNode VisitConcatAlgebraNode(ConcatAlgebraNode node)
{
base.VisitConcatAlgebraNode(node);
List <AlgebraNode> nonEmptyInputs = new List <AlgebraNode>();
foreach (AlgebraNode input in node.Inputs)
{
if (input is NullScanAlgebraNode)
{
// removed by not adding to list.
}
else
{
nonEmptyInputs.Add(input);
}
}
if (nonEmptyInputs.Count == 0)
{
return(CreateNullScan(node.OutputList));
}
if (nonEmptyInputs.Count == 1)
{
int inputIndex = Array.IndexOf(node.Inputs, nonEmptyInputs[0]);
List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>();
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = nonEmptyInputs[0];
foreach (UnitedValueDefinition unitedValueDefinition in node.DefinedValues)
{
ComputedValueDefinition computedValueDefinition = new ComputedValueDefinition();
computedValueDefinition.Target = unitedValueDefinition.Target;
computedValueDefinition.Expression = new RowBufferEntryExpression(unitedValueDefinition.DependendEntries[inputIndex]);
definedValues.Add(computedValueDefinition);
}
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
computeScalarAlgebraNode.OutputList = node.OutputList;
return(computeScalarAlgebraNode);
}
node.Inputs = nonEmptyInputs.ToArray();
// Update dependend entries
for (int i = 0; i < node.DefinedValues.Length; i++)
{
UnitedValueDefinition definition = node.DefinedValues[i];
List <RowBufferEntry> dependendEntries = new List <RowBufferEntry>();
foreach (RowBufferEntry dependendEntry in definition.DependendEntries)
{
bool entryInAnyInput = false;
foreach (AlgebraNode input in node.Inputs)
{
if (ArrayHelpers.Contains(input.OutputList, dependendEntry))
{
entryInAnyInput = true;
break;
}
}
if (entryInAnyInput)
{
dependendEntries.Add(dependendEntry);
}
}
definition.DependendEntries = dependendEntries.ToArray();
}
return(node);
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
if (node.Predicate != null &&
(node.OuterReferences == null || node.OuterReferences.Length == 0) &&
(
node.Op == JoinAlgebraNode.JoinOperator.InnerJoin ||
node.Op == JoinAlgebraNode.JoinOperator.LeftOuterJoin ||
node.Op == JoinAlgebraNode.JoinOperator.RightOuterJoin ||
node.Op == JoinAlgebraNode.JoinOperator.FullOuterJoin)
)
{
RowBufferEntry[] leftDefinedEntries = AstUtil.GetDefinedValueEntries(node.Left);
RowBufferEntry[] rightDefinedEntries = AstUtil.GetDefinedValueEntries(node.Right);
EqualPredicatesExtractor equalPredicatesExtractor = new EqualPredicatesExtractor(leftDefinedEntries, rightDefinedEntries);
ExpressionNode probeResidual = equalPredicatesExtractor.VisitExpression(node.Predicate);
BinaryExpression[] equalPredicates = equalPredicatesExtractor.GetEqualPredicates();
if (equalPredicates.Length > 0)
{
BinaryExpression equalPredicate = equalPredicates[0];
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(probeResidual);
if (equalPredicates.Length > 1)
{
for (int i = 1; i < equalPredicates.Length; i++)
{
expressionBuilder.Push(equalPredicates[i]);
}
expressionBuilder.PushNAry(LogicalOperator.And);
}
probeResidual = expressionBuilder.Pop();
if (probeResidual is ConstantExpression)
{
probeResidual = null;
}
AlgebraNode leftInput = node.Left;
AlgebraNode rightInput = node.Right;
if (node.Op == JoinAlgebraNode.JoinOperator.LeftOuterJoin)
{
node.Op = JoinAlgebraNode.JoinOperator.RightOuterJoin;
leftInput = node.Right;
rightInput = node.Left;
ExpressionNode oldLeft = equalPredicate.Left;
equalPredicate.Left = equalPredicate.Right;
equalPredicate.Right = oldLeft;
}
RowBufferEntry leftEntry;
RowBufferEntryExpression leftAsRowBufferEntryExpression = equalPredicate.Left as RowBufferEntryExpression;
if (leftAsRowBufferEntryExpression != null)
{
leftEntry = leftAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
leftEntry = new RowBufferEntry(equalPredicate.Left.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = leftEntry;
definedValue.Expression = equalPredicate.Left;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = leftInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { definedValue };
leftInput = computeScalarAlgebraNode;
}
RowBufferEntry rightEntry;
RowBufferEntryExpression rightAsRowBufferEntryExpression = equalPredicate.Right as RowBufferEntryExpression;
if (rightAsRowBufferEntryExpression != null)
{
rightEntry = rightAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
rightEntry = new RowBufferEntry(equalPredicate.Right.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = rightEntry;
definedValue.Expression = equalPredicate.Right;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = rightInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { definedValue };
rightInput = computeScalarAlgebraNode;
}
HashMatchAlgebraNode hashMatchAlgebraNode = new HashMatchAlgebraNode();
hashMatchAlgebraNode.Op = node.Op;
hashMatchAlgebraNode.Left = leftInput;
hashMatchAlgebraNode.Right = rightInput;
hashMatchAlgebraNode.BuildKeyEntry = leftEntry;
hashMatchAlgebraNode.ProbeEntry = rightEntry;
hashMatchAlgebraNode.ProbeResidual = probeResidual;
return(hashMatchAlgebraNode);
}
}
return(node);
}
public override TableReference VisitDerivedTableReference(DerivedTableReference node)
{
AlgebraNode algebrizedQuery = Convert(node.Query);
List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>();
for (int i = 0; i < node.DerivedTableBinding.ColumnRefs.Length; i++)
{
RowBufferEntry targetRowBufferEntry = node.DerivedTableBinding.ColumnRefs[i].ValueDefinition.Target;
RowBufferEntry sourceRowBufferEntry = algebrizedQuery.OutputList[i];
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = targetRowBufferEntry;
definedValue.Expression = new RowBufferEntryExpression(sourceRowBufferEntry);
definedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = algebrizedQuery;
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
SetLastAlgebraNode(computeScalarAlgebraNode);
return node;
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
if (node.Predicate != null &&
(node.OuterReferences == null || node.OuterReferences.Length == 0) &&
(
node.Op == JoinAlgebraNode.JoinOperator.InnerJoin ||
node.Op == JoinAlgebraNode.JoinOperator.LeftOuterJoin ||
node.Op == JoinAlgebraNode.JoinOperator.RightOuterJoin ||
node.Op == JoinAlgebraNode.JoinOperator.FullOuterJoin)
)
{
RowBufferEntry[] leftDefinedEntries = AstUtil.GetDefinedValueEntries(node.Left);
RowBufferEntry[] rightDefinedEntries = AstUtil.GetDefinedValueEntries(node.Right);
EqualPredicatesExtractor equalPredicatesExtractor = new EqualPredicatesExtractor(leftDefinedEntries, rightDefinedEntries);
ExpressionNode probeResidual = equalPredicatesExtractor.VisitExpression(node.Predicate);
BinaryExpression[] equalPredicates = equalPredicatesExtractor.GetEqualPredicates();
if (equalPredicates.Length > 0)
{
BinaryExpression equalPredicate = equalPredicates[0];
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(probeResidual);
if (equalPredicates.Length > 1)
{
for (int i = 1; i < equalPredicates.Length; i++)
expressionBuilder.Push(equalPredicates[i]);
expressionBuilder.PushNAry(LogicalOperator.And);
}
probeResidual = expressionBuilder.Pop();
if (probeResidual is ConstantExpression)
probeResidual = null;
AlgebraNode leftInput = node.Left;
AlgebraNode rightInput = node.Right;
if (node.Op == JoinAlgebraNode.JoinOperator.LeftOuterJoin)
{
node.Op = JoinAlgebraNode.JoinOperator.RightOuterJoin;
leftInput = node.Right;
rightInput = node.Left;
ExpressionNode oldLeft = equalPredicate.Left;
equalPredicate.Left = equalPredicate.Right;
equalPredicate.Right = oldLeft;
}
RowBufferEntry leftEntry;
RowBufferEntryExpression leftAsRowBufferEntryExpression = equalPredicate.Left as RowBufferEntryExpression;
if (leftAsRowBufferEntryExpression != null)
{
leftEntry = leftAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
leftEntry = new RowBufferEntry(equalPredicate.Left.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = leftEntry;
definedValue.Expression = equalPredicate.Left;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = leftInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] {definedValue};
leftInput = computeScalarAlgebraNode;
}
RowBufferEntry rightEntry;
RowBufferEntryExpression rightAsRowBufferEntryExpression = equalPredicate.Right as RowBufferEntryExpression;
if (rightAsRowBufferEntryExpression != null)
{
rightEntry = rightAsRowBufferEntryExpression.RowBufferEntry;
}
else
{
rightEntry = new RowBufferEntry(equalPredicate.Right.ExpressionType);
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = rightEntry;
definedValue.Expression = equalPredicate.Right;
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = rightInput;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] {definedValue};
rightInput = computeScalarAlgebraNode;
}
HashMatchAlgebraNode hashMatchAlgebraNode = new HashMatchAlgebraNode();
hashMatchAlgebraNode.Op = node.Op;
hashMatchAlgebraNode.Left = leftInput;
hashMatchAlgebraNode.Right = rightInput;
hashMatchAlgebraNode.BuildKeyEntry = leftEntry;
hashMatchAlgebraNode.ProbeEntry = rightEntry;
hashMatchAlgebraNode.ProbeResidual = probeResidual;
return hashMatchAlgebraNode;
}
}
return node;
}
public override AlgebraNode VisitConcatAlgebraNode(ConcatAlgebraNode node)
{
base.VisitConcatAlgebraNode(node);
List<AlgebraNode> nonEmptyInputs = new List<AlgebraNode>();
foreach (AlgebraNode input in node.Inputs)
{
if (input is NullScanAlgebraNode)
{
// removed by not adding to list.
}
else
{
nonEmptyInputs.Add(input);
}
}
if (nonEmptyInputs.Count == 0)
return CreateNullScan(node.OutputList);
if (nonEmptyInputs.Count == 1)
{
int inputIndex = Array.IndexOf(node.Inputs, nonEmptyInputs[0]);
List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>();
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = nonEmptyInputs[0];
foreach (UnitedValueDefinition unitedValueDefinition in node.DefinedValues)
{
ComputedValueDefinition computedValueDefinition = new ComputedValueDefinition();
computedValueDefinition.Target = unitedValueDefinition.Target;
computedValueDefinition.Expression = new RowBufferEntryExpression(unitedValueDefinition.DependendEntries[inputIndex]);
definedValues.Add(computedValueDefinition);
}
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
computeScalarAlgebraNode.OutputList = node.OutputList;
return computeScalarAlgebraNode;
}
node.Inputs = nonEmptyInputs.ToArray();
// Update dependend entries
for (int i = 0; i < node.DefinedValues.Length; i++)
{
UnitedValueDefinition definition = node.DefinedValues[i];
List<RowBufferEntry> dependendEntries = new List<RowBufferEntry>();
foreach (RowBufferEntry dependendEntry in definition.DependendEntries)
{
bool entryInAnyInput = false;
foreach (AlgebraNode input in node.Inputs)
{
if (ArrayHelpers.Contains(input.OutputList, dependendEntry))
{
entryInAnyInput = true;
break;
}
}
if (entryInAnyInput)
dependendEntries.Add(dependendEntry);
}
definition.DependendEntries = dependendEntries.ToArray();
}
return node;
}
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);
}
public override AlgebraNode VisitAggregateAlgebraNode(AggregateAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
if (node.Input is NullScanAlgebraNode)
{
if (node.Groups != null && node.Groups.Length > 0)
{
// Grouped queries return nothing on empty input.
return CreateNullScan(node.OutputList);
}
else
{
// Non-grouped aggregation. We return the result value of the aggregates
// executed against an empty input as a single row.
List<RowBufferEntry> outputList = new List<RowBufferEntry>();
List<ComputedValueDefinition> emptyValueList = new List<ComputedValueDefinition>();
foreach (AggregatedValueDefinition definedValue in node.DefinedValues)
{
IAggregator aggregator = definedValue.Aggregator;
aggregator.Init();
object emptyValue = aggregator.Terminate();
ComputedValueDefinition computedBufferedValue = new ComputedValueDefinition();
computedBufferedValue.Target = definedValue.Target;
computedBufferedValue.Expression = LiteralExpression.FromTypedValue(emptyValue, aggregator.ReturnType);
emptyValueList.Add(computedBufferedValue);
outputList.Add(computedBufferedValue.Target);
}
ConstantScanAlgebraNode constantScanAlgebraNode = new ConstantScanAlgebraNode();
constantScanAlgebraNode.DefinedValues = emptyValueList.ToArray();
constantScanAlgebraNode.OutputList = outputList.ToArray();
return constantScanAlgebraNode;
}
}
return node;
}
private RuntimeComputedValueOutput[] GetDefinedValues(RowBufferEntry[] outputList, ComputedValueDefinition[] definedValues, params BoundRowBufferEntrySet[] boundRowBufferEntrySets)
{
RuntimeComputedValueOutput[] result = new RuntimeComputedValueOutput[definedValues.Length];
for (int i = 0; i < definedValues.Length; i++)
{
RuntimeComputedValueOutput definedValue = new RuntimeComputedValueOutput();
definedValue.Expression = CreateRuntimeExpression(definedValues[i].Expression, boundRowBufferEntrySets);
definedValue.TargetIndex = Array.IndexOf(outputList, definedValues[i].Target);
result[i] = definedValue;
}
return result;
}
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 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 void CreateBufferedValue(ExpressionNode expression, ICollection<ComputedValueDefinition> computedColumnList, ICollection<RowBufferEntry> columnList, IEnumerable<ComputedValueDefinition> alreadyComputedBufferedValues)
{
if (alreadyComputedBufferedValues != null)
expression = ReplaceAlreadyComputedSubsequences(expression, alreadyComputedBufferedValues);
foreach (ComputedValueDefinition computedBufferedValue in computedColumnList)
{
if (expression.IsStructuralEqualTo(computedBufferedValue.Expression))
{
columnList.Add(computedBufferedValue.Target);
return;
}
}
RowBufferEntryExpression rowBufferExpression = expression as RowBufferEntryExpression;
if (rowBufferExpression != null)
{
columnList.Add(rowBufferExpression.RowBufferEntry);
}
else
{
RowBufferEntry rowBufferEntry = new RowBufferEntry(expression.ExpressionType);
columnList.Add(rowBufferEntry);
ComputedValueDefinition computedValue = new ComputedValueDefinition();
computedValue.Target = rowBufferEntry;
computedValue.Expression = expression;
computedColumnList.Add(computedValue);
}
}
public RowBufferEntryReplacer(ComputedValueDefinition[] definedValues)
{
_definedValues = definedValues;
}