public virtual AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
node.Predicate = VisitExpression(node.Predicate);
return(node);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
switch (node.Input.NodeType)
{
case AstNodeType.SortAlgebraNode:
case AstNodeType.ResultAlgebraNode:
case AstNodeType.TopAlgebraNode:
return(PushOverUnary(node));
case AstNodeType.FilterAlgebraNode:
return(MergeWithFilter(node));
case AstNodeType.ComputeScalarAlgebraNode:
return(PushOverComputeScalar(node));
case AstNodeType.AggregateAlgebraNode:
return(PushOverAggregate(node));
case AstNodeType.JoinAlgebraNode:
return(PushOverJoin(node));
case AstNodeType.ConcatAlgebraNode:
return(PushOverConcat(node));
default:
return(base.VisitFilterAlgebraNode(node));
}
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
switch (node.Input.NodeType)
{
case AstNodeType.SortAlgebraNode:
case AstNodeType.ResultAlgebraNode:
case AstNodeType.TopAlgebraNode:
return PushOverUnary(node);
case AstNodeType.FilterAlgebraNode:
return MergeWithFilter(node);
case AstNodeType.ComputeScalarAlgebraNode:
return PushOverComputeScalar(node);
case AstNodeType.AggregateAlgebraNode:
return PushOverAggregate(node);
case AstNodeType.JoinAlgebraNode:
return PushOverJoin(node);
case AstNodeType.ConcatAlgebraNode:
return PushOverConcat(node);
default:
return base.VisitFilterAlgebraNode(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;
}
private static FilterAlgebraNode GetFilterFromAndParts(IList <ExpressionNode> andParts, AlgebraNode input)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = input;
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, andParts);
return(filterAlgebraNode);
}
private AlgebraNode PushOverUnary(FilterAlgebraNode node)
{
UnaryAlgebraNode inputNode = (UnaryAlgebraNode)node.Input;
node.Input = inputNode.Input;
inputNode.Input = VisitAlgebraNode(node);
return(inputNode);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.OutputList = RemovedUnneededRowBufferColumns(node.OutputList);
AddNeededRowBufferEntryReferences(node.Predicate);
return(base.VisitFilterAlgebraNode(node));
}
private AlgebraNode PushOverComputeScalar(FilterAlgebraNode node)
{
// Predicates can be pushed over a compute scalar if it does not contain any row buffer entries
// that are defined by the compute scalar node.
ComputeScalarAlgebraNode inputNode = (ComputeScalarAlgebraNode)node.Input;
return(PushOverValueDefininingUnary(inputNode.DefinedValues, node));
}
public override AstElement Clone(Dictionary<AstElement, AstElement> alreadyClonedElements)
{
FilterAlgebraNode result = new FilterAlgebraNode();
result.StatisticsIterator = StatisticsIterator;
result.OutputList = ArrayHelpers.Clone(OutputList);
result.Input = (AlgebraNode)Input.Clone(alreadyClonedElements);
result.Predicate = (ExpressionNode)_predicate.Clone(alreadyClonedElements);
return result;
}
private AlgebraNode MergeWithFilter(FilterAlgebraNode node)
{
// The input is also a filter, so we can merge this predicate with
// the input filter.
FilterAlgebraNode inputNode = (FilterAlgebraNode)node.Input;
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, node.Predicate);
return(VisitAlgebraNode(inputNode));
}
public override AstElement Clone(Dictionary <AstElement, AstElement> alreadyClonedElements)
{
FilterAlgebraNode result = new FilterAlgebraNode();
result.StatisticsIterator = StatisticsIterator;
result.OutputList = ArrayHelpers.Clone(OutputList);
result.Input = (AlgebraNode)Input.Clone(alreadyClonedElements);
result.Predicate = (ExpressionNode)_predicate.Clone(alreadyClonedElements);
return(result);
}
private static AlgebraNode WrapWithFilter(AlgebraNode input, ExpressionNode predicate)
{
if (predicate == null)
return input;
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = input;
filterAlgebraNode.Predicate = predicate;
return filterAlgebraNode;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
_xmlWriter.WriteStartElement("filterAlgebraNode");
WriteAstNode("input", node.Input);
WriteAstNode("predicate", node.Predicate);
_xmlWriter.WriteEndElement();
return(node);
}
private AlgebraNode PushOverFilter(ComputeScalarAlgebraNode node)
{
FilterAlgebraNode filterAlgebraNode = (FilterAlgebraNode)node.Input;
if (filterAlgebraNode.Input is TableAlgebraNode)
{
// We don't push a compute scalar over the input if this is already a table scan.
return(node);
}
return(PushOverUnary(node));
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
SetLastAlgebraNode(node.Input);
_probingEnabledStack.Push(false);
node.Predicate = VisitExpression(node.Predicate);
_probingEnabledStack.Pop();
node.Input = GetAndResetLastNode();
return(node);
}
private static AlgebraNode WrapWithFilter(AlgebraNode input, ExpressionNode predicate)
{
if (predicate == null)
{
return(input);
}
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = input;
filterAlgebraNode.Predicate = predicate;
return(filterAlgebraNode);
}
private AlgebraNode PushOverAggregate(FilterAlgebraNode node)
{
// TODO: It is not that easy.
// For example this condition can be pushed 'GroupCol = Value' while this can't: 'GroupCol = Value OR Func(const) = const'
// Formally, a predicate can be pushed over an aggregate if and only if all disjuncts of the predicate's CNF do reference
// at least one grouping column.
// Since this requires cloning of the predicate and heavy rewriting this is not done (yet).
return(base.VisitFilterAlgebraNode(node));
/*
* // Predicates can be pushed over an aggregation if it does not contain any aggregate function.
* AggregateAlgebraNode inputNode = (AggregateAlgebraNode)node.Input;
* return PushOverValueDefininingUnary(inputNode.DefinedValues, node);
*/
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
// Check for null rejecting conditions.
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
RowBufferEntry[] rowBufferEntries = AstUtil.GetRowBufferEntryReferences(andPart);
foreach (RowBufferEntry rowBufferEntry in rowBufferEntries)
{
if (AstUtil.ExpressionYieldsNullOrFalseIfRowBufferEntryNull(andPart, rowBufferEntry))
AddNullRejectedTable(rowBufferEntry);
}
}
return base.VisitFilterAlgebraNode(node);
}
private AlgebraNode PullFilterUp(UnaryAlgebraNode unaryAlgebraNode)
{
unaryAlgebraNode.Input = VisitAlgebraNode(unaryAlgebraNode.Input);
FilterAlgebraNode filterAlgebraNode = unaryAlgebraNode.Input as FilterAlgebraNode;
if (filterAlgebraNode == null)
{
return(unaryAlgebraNode);
}
else
{
unaryAlgebraNode.Input = filterAlgebraNode.Input;
filterAlgebraNode.Input = unaryAlgebraNode;
return(filterAlgebraNode);
}
}
private AlgebraNode PushOverConcat(FilterAlgebraNode node)
{
ConcatAlgebraNode inputNode = (ConcatAlgebraNode)node.Input;
for (int i = 0; i < inputNode.Inputs.Length; i++)
{
ExpressionNode predicate = (ExpressionNode)node.Predicate.Clone();
ConcatRowBufferEntryReplacer concatRowBufferEntryReplacer = new ConcatRowBufferEntryReplacer(inputNode.DefinedValues, i);
predicate = concatRowBufferEntryReplacer.VisitExpression(predicate);
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = inputNode.Inputs[i];
filterAlgebraNode.Predicate = predicate;
inputNode.Inputs[i] = VisitAlgebraNode(filterAlgebraNode);
}
return(inputNode);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
ShowPlanElement inputElement = ConvertNode(node.Input);
PropertyListBuilder propertyListBuilder = new PropertyListBuilder();
AddRowBufferEntries(propertyListBuilder, Resources.ShowPlanGroupOutputList, node.OutputList);
AddStatistics(propertyListBuilder, node.StatisticsIterator);
propertyListBuilder.Write(Resources.ShowPlanKeyPredicate, node.Predicate.GenerateSource());
IList <ShowPlanProperty> properties = propertyListBuilder.ToList();
ShowPlanElement element = new ShowPlanElement(ShowPlanOperator.Filter, properties, inputElement);
_currentElement = element;
return(node);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
// Check for null rejecting conditions.
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
RowBufferEntry[] rowBufferEntries = AstUtil.GetRowBufferEntryReferences(andPart);
foreach (RowBufferEntry rowBufferEntry in rowBufferEntries)
{
if (AstUtil.ExpressionYieldsNullOrFalseIfRowBufferEntryNull(andPart, rowBufferEntry))
{
AddNullRejectedTable(rowBufferEntry);
}
}
}
return(base.VisitFilterAlgebraNode(node));
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
ConstantExpression predicateAsConstant = node.Predicate as ConstantExpression;
if (predicateAsConstant != null)
{
if (predicateAsConstant.AsBoolean)
{
return(node.Input);
}
else
{
return(CreateNullScan(node.OutputList));
}
}
return(NullScanIfInputIsNullScan(node));
}
public override TableReference VisitJoinedTableReference(JoinedTableReference node)
{
TableReference nonCteTableRef;
if (IsTableReferenceToCurrentCommonTableBinding(node.Left))
{
nonCteTableRef = node.Right;
}
else if (IsTableReferenceToCurrentCommonTableBinding(node.Right))
{
nonCteTableRef = node.Left;
}
else
{
nonCteTableRef = null;
}
if (nonCteTableRef != null)
{
Debug.Assert(node.JoinType == JoinType.Inner);
AlgebraNode algebrizedPath = ConvertAstNode(nonCteTableRef);
SetLastAlgebraNode(algebrizedPath);
if (node.Condition != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = node.Condition;
SetLastAlgebraNode(filterAlgebraNode);
}
return(node);
}
JoinAlgebraNode algebraNode = new JoinAlgebraNode();
algebraNode.Left = ConvertAstNode(node.Left);
algebraNode.Right = ConvertAstNode(node.Right);
algebraNode.Predicate = node.Condition;
switch (node.JoinType)
{
case JoinType.Inner:
algebraNode.Op = JoinAlgebraNode.JoinOperator.InnerJoin;
break;
case JoinType.LeftOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
break;
case JoinType.RightOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.RightOuterJoin;
break;
case JoinType.FullOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.FullOuterJoin;
break;
}
SetLastAlgebraNode(algebraNode);
return(node);
}
public override QueryNode VisitSelectQuery(SelectQuery query)
{
// Calculate needed row buffers
RowBufferCalculator rowBufferCalculator = query.RowBufferCalculator;
// Emit FROM
if (query.TableReferences != null)
{
Visit(query.TableReferences);
}
else
{
ConstantScanAlgebraNode constantScanAlgebraNode = new ConstantScanAlgebraNode();
constantScanAlgebraNode.DefinedValues = new ComputedValueDefinition[0];
SetLastAlgebraNode(constantScanAlgebraNode);
}
// Emit WHERE
if (query.WhereClause != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = query.WhereClause;
SetLastAlgebraNode(filterAlgebraNode);
}
// Emit GROUP BY
if (query.GroupByColumns != null || query.IsAggregated)
{
EmitComputeScalarIfNeeded(rowBufferCalculator.ComputedGroupColumns);
List <AggregatedValueDefinition> definedValues = new List <AggregatedValueDefinition>();
foreach (AggregateExpression aggregateDependency in query.AggregateDependencies)
{
definedValues.Add(aggregateDependency.ValueDefinition);
}
if (query.GroupByColumns != null)
{
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.GroupColumns;
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
SetLastAlgebraNode(sortAlgebraNode);
}
AggregateAlgebraNode algebraNode = new AggregateAlgebraNode();
algebraNode.Input = GetLastAlgebraNode();
algebraNode.DefinedValues = definedValues.ToArray();
algebraNode.Groups = rowBufferCalculator.GroupColumns;
SetLastAlgebraNode(algebraNode);
}
// Emit HAVING
if (query.HavingClause != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = query.HavingClause;
SetLastAlgebraNode(filterAlgebraNode);
}
// Emit compute scalar to calculate expressions needed in SELECT and ORDER BY
EmitComputeScalarIfNeeded(rowBufferCalculator.ComputedSelectAndOrderColumns);
// Emit DISTINCT and ORDER BY
if (query.IsDistinct && query.OrderByColumns != null)
{
List <RowBufferEntry> sortEntries = new List <RowBufferEntry>();
List <SortOrder> sortOrderList = new List <SortOrder>();
for (int i = 0; i < query.OrderByColumns.Length; i++)
{
sortEntries.Add(rowBufferCalculator.OrderColumns[i]);
sortOrderList.Add(query.OrderByColumns[i].SortOrder);
}
foreach (RowBufferEntry selectColumn in rowBufferCalculator.SelectColumns)
{
bool selectColumnMustBeSorted = !sortEntries.Contains(selectColumn);
if (selectColumnMustBeSorted)
{
sortEntries.Add(selectColumn);
sortOrderList.Add(SortOrder.Ascending);
}
}
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = sortEntries.ToArray();
sortAlgebraNode.SortOrders = sortOrderList.ToArray();
SetLastAlgebraNode(sortAlgebraNode);
}
else
{
if (query.IsDistinct)
{
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.SelectColumns;
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
SetLastAlgebraNode(sortAlgebraNode);
}
if (query.OrderByColumns != null)
{
List <SortOrder> sortOrderList = new List <SortOrder>();
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
{
sortOrderList.Add(orderByColumn.SortOrder);
}
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.OrderColumns;
sortAlgebraNode.SortOrders = sortOrderList.ToArray();
SetLastAlgebraNode(sortAlgebraNode);
}
}
// Emit TOP
if (query.TopClause != null)
{
TopAlgebraNode algebraNode = new TopAlgebraNode();
algebraNode.Input = GetLastAlgebraNode();
algebraNode.Limit = query.TopClause.Value;
if (query.TopClause.WithTies)
{
algebraNode.TieEntries = rowBufferCalculator.OrderColumns;
}
SetLastAlgebraNode(algebraNode);
}
// Emit select list
List <string> columnNames = new List <string>();
foreach (SelectColumn columnSource in query.SelectColumns)
{
if (columnSource.Alias != null)
{
columnNames.Add(columnSource.Alias.Text);
}
else
{
columnNames.Add(null);
}
}
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = GetLastAlgebraNode();
resultAlgebraNode.OutputList = rowBufferCalculator.SelectColumns;
resultAlgebraNode.ColumnNames = columnNames.ToArray();
SetLastAlgebraNode(resultAlgebraNode);
return(query);
}
public virtual AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
node.Predicate = VisitExpression(node.Predicate);
return node;
}
private AlgebraNode PushOverJoin(FilterAlgebraNode node)
{
JoinAlgebraNode inputNode = (JoinAlgebraNode)node.Input;
// Get declared tables of left and right
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(inputNode.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(inputNode.Right);
// Obviously, we cannot merge the filter with the join if the join is an outer join
// (since it would change the join's semantics).
//
// Another less obvious restriction is that we cannot merge a filter with the join if
// the join has a passthru predicate. In case the passthru predicte evaluates to true
// the filter would not be applied. However, we are allowed to push the filter the over
// join.
bool canMerge = inputNode.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin &&
inputNode.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
inputNode.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
inputNode.PassthruPredicate == null;
if (canMerge)
{
// We can merge the filter with the condition of the join.
//
// However, we have to make sure that the predicate does not reference the probe column.
// Since not having a probe column is the most common case, we don't always split the
// predicate into conjuncts.
if (inputNode.ProbeBufferEntry == null || !ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(node.Predicate), inputNode.ProbeBufferEntry))
{
// Either there is no probe column defined or the filter does not reference it. That means
// no splitting necessary, we can just merge the whole predicate with the join predicate.
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, node.Predicate);
return(VisitAlgebraNode(inputNode));
}
else
{
// Unfortunately, the filter references the probe column. Now let's check whether we can merge
// conjuncts of the predicate.
List <ExpressionNode> remainingAndParts = new List <ExpressionNode>();
List <ExpressionNode> mergableAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
bool andPartReferencesProbeColumn = ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(andPart), inputNode.ProbeBufferEntry);
if (andPartReferencesProbeColumn)
{
remainingAndParts.Add(andPart);
}
else
{
mergableAndParts.Add(andPart);
}
}
if (mergableAndParts.Count > 0)
{
ExpressionNode combinedMergableAndParts = AstUtil.CombineConditions(LogicalOperator.And, mergableAndParts.ToArray());
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, combinedMergableAndParts);
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (node.Predicate == null)
{
return(VisitAlgebraNode(inputNode));
}
}
}
}
else
{
// The condition cannot be merged. Now we try to push AND-parts over the join.
List <ExpressionNode> leftAndParts = new List <ExpressionNode>();
List <ExpressionNode> rightAndParts = new List <ExpressionNode>();
List <ExpressionNode> remainingAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
bool andPartReferencesProbeColumn = inputNode.ProbeBufferEntry != null &&
ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(andPart), inputNode.ProbeBufferEntry);
if (!andPartReferencesProbeColumn && AstUtil.AllowsLeftPushOver(inputNode.Op) && AstUtil.ExpressionDoesNotReference(andPart, rightDefinedValues))
{
// The AND-part depends only on the LHS and the join is inner/left.
// So we are allowed to push this AND-part down.
leftAndParts.Add(andPart);
}
else if (!andPartReferencesProbeColumn && AstUtil.AllowsRightPushOver(inputNode.Op) && AstUtil.ExpressionDoesNotReference(andPart, leftDefinedValues))
{
// The AND-part depends only on the RHS and the join is inner/right.
// So we are allowed to push this AND-part down.
rightAndParts.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
if (leftAndParts.Count > 0)
{
inputNode.Left = GetFilterFromAndParts(leftAndParts, inputNode.Left);
}
if (rightAndParts.Count > 0)
{
inputNode.Right = GetFilterFromAndParts(rightAndParts, inputNode.Right);
}
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (node.Predicate == null)
{
return(VisitAlgebraNode(inputNode));
}
}
node.Input = VisitAlgebraNode(node.Input);
return(node);
}
public override TableReference VisitJoinedTableReference(JoinedTableReference node)
{
TableReference nonCteTableRef;
if (IsTableReferenceToCurrentCommonTableBinding(node.Left))
nonCteTableRef = node.Right;
else if (IsTableReferenceToCurrentCommonTableBinding(node.Right))
nonCteTableRef = node.Left;
else
nonCteTableRef = null;
if (nonCteTableRef != null)
{
Debug.Assert(node.JoinType == JoinType.Inner);
AlgebraNode algebrizedPath = ConvertAstNode(nonCteTableRef);
SetLastAlgebraNode(algebrizedPath);
if (node.Condition != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = node.Condition;
SetLastAlgebraNode(filterAlgebraNode);
}
return node;
}
JoinAlgebraNode algebraNode = new JoinAlgebraNode();
algebraNode.Left = ConvertAstNode(node.Left);
algebraNode.Right = ConvertAstNode(node.Right);
algebraNode.Predicate = node.Condition;
switch (node.JoinType)
{
case JoinType.Inner:
algebraNode.Op = JoinAlgebraNode.JoinOperator.InnerJoin;
break;
case JoinType.LeftOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
break;
case JoinType.RightOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.RightOuterJoin;
break;
case JoinType.FullOuter:
algebraNode.Op = JoinAlgebraNode.JoinOperator.FullOuterJoin;
break;
}
SetLastAlgebraNode(algebraNode);
return node;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
SetLastAlgebraNode(node.Input);
_probingEnabledStack.Push(false);
node.Predicate = VisitExpression(node.Predicate);
_probingEnabledStack.Pop();
node.Input = GetAndResetLastNode();
return node;
}
private AlgebraNode PushOverUnary(FilterAlgebraNode node)
{
UnaryAlgebraNode inputNode = (UnaryAlgebraNode) node.Input;
node.Input = inputNode.Input;
inputNode.Input = VisitAlgebraNode(node);
return inputNode;
}
public override ExpressionNode VisitBinaryExpression(BinaryExpression expression)
{
if (expression.Op != BinaryOperator.LogicalAnd &&
expression.Op != BinaryOperator.LogicalOr)
{
return(base.VisitBinaryExpression(expression));
}
if (expression.Op == BinaryOperator.LogicalAnd)
{
// AND
expression.Left = VisitExpression(expression.Left);
expression.Right = VisitExpression(expression.Right);
return(expression);
}
else
{
// OR
AlgebraNode input = GetAndResetLastNode();
_probingEnabledStack.Push(false);
List <ExpressionNode> scalarOrParts = new List <ExpressionNode>();
List <AlgebraNode> algebrizedOrParts = new List <AlgebraNode>();
foreach (ExpressionNode orPart in AstUtil.SplitCondition(LogicalOperator.Or, expression))
{
if (!AstUtil.ContainsSubselect(orPart))
{
scalarOrParts.Add(orPart);
}
else
{
ExpressionNode replacedOrPart = VisitExpression(orPart);
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetAndResetLastNode();
filterAlgebraNode.Predicate = replacedOrPart;
algebrizedOrParts.Add(filterAlgebraNode);
}
}
if (scalarOrParts.Count > 0)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.Or, scalarOrParts);
filterAlgebraNode.Input = CreateConstantScan();
algebrizedOrParts.Insert(0, filterAlgebraNode);
}
_probingEnabledStack.Pop();
ConcatAlgebraNode concat = new ConcatAlgebraNode();
concat.DefinedValues = new UnitedValueDefinition[0];
concat.Inputs = algebrizedOrParts.ToArray();
RowBufferEntry probeColumn = CreateProbeColumn();
JoinAlgebraNode leftSemiJoinBetweenInputAndConcat = new JoinAlgebraNode();
leftSemiJoinBetweenInputAndConcat.Op = JoinAlgebraNode.JoinOperator.LeftSemiJoin;
leftSemiJoinBetweenInputAndConcat.PassthruPredicate = CurrentPassthruPredicate;
leftSemiJoinBetweenInputAndConcat.ProbeBufferEntry = probeColumn;
leftSemiJoinBetweenInputAndConcat.Left = input;
leftSemiJoinBetweenInputAndConcat.Right = concat;
SetLastAlgebraNode(leftSemiJoinBetweenInputAndConcat);
return(CreateProbeColumnRef(probeColumn));
}
}
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)
{
// Check if node only consists of INNER join nodes and simple table reference nodes.
// This algorithm assumes that the table references have been lineraized so that
//
// - JoinedTableReference appear on the LHS only (the last one must be NamedTableReference ovbiviously)
// - NamedTableReference appear on the RHS only
//
// While scanning the node's children we create a list of all JoinedTableReferences and
// NamedTableReferences.
InnerJoinTableExtractor innerJoinTableExtractor = new InnerJoinTableExtractor();
innerJoinTableExtractor.Visit(node);
if (!innerJoinTableExtractor.ConsistsOnlyOfInnerJoinsFiltersAndTables)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
return node;
}
else
{
TableAlgebraNode[] algebraNodes = innerJoinTableExtractor.GetTableNodes();
Dictionary<TableRefBinding,TableAlgebraNode> tableRefToNodeDictionary = new Dictionary<TableRefBinding, TableAlgebraNode>();
List<TableRefBinding> tableList = new List<TableRefBinding>();
foreach (TableAlgebraNode algebraNode in algebraNodes)
{
tableRefToNodeDictionary.Add(algebraNode.TableRefBinding, algebraNode);
tableList.Add(algebraNode.TableRefBinding);
}
// Create a mapping RowBufferEntry -> ColumnRefBinding
Dictionary<RowBufferEntry, ColumnRefBinding> rowBufferColumnDictionary = new Dictionary<RowBufferEntry, ColumnRefBinding>();
foreach (TableRefBinding tableRefBinding in tableList)
{
foreach (ColumnRefBinding columnRefBinding in tableRefBinding.ColumnRefs)
rowBufferColumnDictionary.Add(columnRefBinding.ValueDefinition.Target, columnRefBinding);
}
// Create list of all possible join conditions and remaining AND-parts.
List<JoinCondition> joinConditionList = new List<JoinCondition>();
List<ExpressionNode> andPartList = new List<ExpressionNode>();
ExpressionNode filter = AstUtil.CombineConditions(LogicalOperator.And, innerJoinTableExtractor.GetFilters());
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, filter))
{
JoinCondition joinCondition = ConvertToJoinCondition(rowBufferColumnDictionary, andPart);
if (joinCondition != null)
joinConditionList.Add(joinCondition);
else
andPartList.Add(andPart);
}
// After creating the list of all join conditions and AND-parts we have all we need to create
// an optimimal join order between all tables of this part of the table tree.
JoinOrder bestJoinOrder = GetBestJoinOrder(tableList.ToArray(), joinConditionList.ToArray(), andPartList.ToArray());
// Get all tables that are introduced by this join order
Dictionary<RowBufferEntry, ColumnValueDefinition> introducedColumns = GetIntroducedColumns(bestJoinOrder);
// Combine AND-part list with all unused join conditions.
andPartList.AddRange(bestJoinOrder.UnusedConditions);
// Now we will re-create this part of the tree using the this join order.
AlgebraNode lastAlgebraNode = null;
for (int joinIndex = 0; joinIndex < bestJoinOrder.Joins.Length; joinIndex++)
{
Join join = bestJoinOrder.Joins[joinIndex];
AlgebraNode tableInput;
TableAlgebraNode tableNode = tableRefToNodeDictionary[join.TableRefBinding];
ExpressionNode tableFilter = ExtractConditionsApplicableToTable(introducedColumns, andPartList, join.TableRefBinding);
if (tableFilter == null)
{
tableInput = tableNode;
}
else
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = tableNode;
filterAlgebraNode.Predicate = tableFilter;
tableInput = filterAlgebraNode;
}
if (lastAlgebraNode == null)
{
// This was the first one.
lastAlgebraNode = tableInput;
}
else
{
// Not the first one, we can create a join with the current table reference
// and last table reference.
// Get all AND-parts that can be applied to the tables already joined.
// This expression is merged to one condition.
ExpressionNode[] applicableAndParts = GetAndPartsApplicableToJoin(introducedColumns, bestJoinOrder, joinIndex, andPartList, true);
ExpressionNode condition = AstUtil.CombineConditions(LogicalOperator.And, applicableAndParts);
ExpressionNode joinCondition;
if (join.JoinCondition == null)
joinCondition = null;
else
joinCondition = join.JoinCondition.ToExpression();
ExpressionNode completeCondition = AstUtil.CombineConditions(LogicalOperator.And, condition, joinCondition);
JoinAlgebraNode joinAlgebraNode = new JoinAlgebraNode();
joinAlgebraNode.Op = JoinAlgebraNode.JoinOperator.InnerJoin;
joinAlgebraNode.Left = lastAlgebraNode;
joinAlgebraNode.Right = tableInput;
joinAlgebraNode.Predicate = completeCondition;
// Next time this newly created join is the last table reference.
lastAlgebraNode = joinAlgebraNode;
}
}
return lastAlgebraNode;
}
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
// Get defined values of left and right
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(node.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(node.Right);
List<ExpressionNode> andPartsWithinJoin = new List<ExpressionNode>();
// Try to pull up AND-parts that contain outer references from a left sided filter and combine
// them with the join predicate.
//
// NOTE: This is only possible if the join is not a LEFT OUTER or FULL OUTER JOIN since this
// operation would change the join's semantic.
if (node.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
FilterAlgebraNode leftAsFilter = node.Left as FilterAlgebraNode;
if (leftAsFilter != null)
{
List<ExpressionNode> remainingAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, leftAsFilter.Predicate))
{
if (AndPartHasOuterReference(andPart, leftDefinedValues))
andPartsWithinJoin.Add(andPart);
else
remainingAndParts.Add(andPart);
}
leftAsFilter.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (leftAsFilter.Predicate == null)
node.Left = leftAsFilter.Input;
}
}
// Try to pull up AND-parts that contain outer references from a right sided filter and combine
// them with the join predicate.
//
// NOTE: This is only possible if the join is not a RIGHT OUTER or FULL OUTER JOIN since this
// operation would change the join's semantic.
if (node.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
FilterAlgebraNode rightAsFilter = node.Right as FilterAlgebraNode;
if (rightAsFilter != null)
{
List<ExpressionNode> remainingAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, rightAsFilter.Predicate))
{
if (AndPartHasOuterReference(andPart, rightDefinedValues))
andPartsWithinJoin.Add(andPart);
else
remainingAndParts.Add(andPart);
}
rightAsFilter.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (rightAsFilter.Predicate == null)
node.Right = rightAsFilter.Input;
}
}
// If we found any AND-parts that could be pulled up, merge them with the join predicate.
if (andPartsWithinJoin.Count > 0)
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, node.Predicate, AstUtil.CombineConditions(LogicalOperator.And, andPartsWithinJoin));
// Now we try to extract AND-parts that contain outer references from the join predicate itself.
//
// NOTE: This is only possible if the node is not an OUTER JOIN. If the node is a SEMI JOIN the
// operation is only legal if the AND-part does not reference any columns from the side that is
// is used as filter criteria (i.e. for LSJ this is the right side, for RSJ this is the left
// side).
if (node.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin &&
node.Predicate != null)
{
List<ExpressionNode> andPartsAboveJoin = new List<ExpressionNode>();
List<ExpressionNode> remainingAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
if (AndPartHasOuterReference(andPart, leftDefinedValues, rightDefinedValues) &&
SemiJoinDoesNotDependOn(node.Op, andPart, leftDefinedValues, rightDefinedValues))
andPartsAboveJoin.Add(andPart);
else
remainingAndParts.Add(andPart);
}
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (andPartsAboveJoin.Count > 0)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, andPartsAboveJoin);
filterAlgebraNode.Input = node;
return filterAlgebraNode;
}
}
return node;
}
private AlgebraNode PushOverValueDefininingUnary(IEnumerable <ValueDefinition> definedValues, FilterAlgebraNode node)
{
UnaryAlgebraNode inputNode = (UnaryAlgebraNode)node.Input;
List <ExpressionNode> nonDependingAndParts = new List <ExpressionNode>();
List <ExpressionNode> dependingAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
RowBufferEntry[] rowBufferEntries = AstUtil.GetRowBufferEntryReferences(andPart);
bool dependsOnDefinedValue = false;
foreach (ValueDefinition definedValue in definedValues)
{
if (ArrayHelpers.Contains(rowBufferEntries, definedValue.Target))
{
dependsOnDefinedValue = true;
break;
}
}
if (dependsOnDefinedValue)
{
dependingAndParts.Add(andPart);
}
else
{
nonDependingAndParts.Add(andPart);
}
}
if (nonDependingAndParts.Count > 0)
{
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, dependingAndParts);
inputNode.Input = GetFilterFromAndParts(nonDependingAndParts, inputNode.Input);
if (node.Predicate == null)
{
node.Input = inputNode.Input;
inputNode.Input = VisitAlgebraNode(node);
return(inputNode);
}
}
node.Input = VisitAlgebraNode(node.Input);
return(node);
}
public override ExpressionNode VisitAllAnySubselect(AllAnySubselect expression)
{
expression.Left = VisitExpression(expression.Left);
ResultAlgebraNode algebrizedQuery = Algebrizer.Convert(expression.Query);
ExpressionNode leftExpression = expression.Left;
RowBufferEntryExpression rightExpression = new RowBufferEntryExpression();
rightExpression.RowBufferEntry = algebrizedQuery.OutputList[0];
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(leftExpression);
expressionBuilder.Push(rightExpression);
expressionBuilder.PushBinary(expression.Op);
bool negated = (expression.Type == AllAnySubselect.AllAnyType.All);
if (negated)
{
expressionBuilder.PushUnary(UnaryOperator.LogicalNot);
expressionBuilder.Push(leftExpression);
expressionBuilder.PushIsNull();
expressionBuilder.Push(rightExpression);
expressionBuilder.PushIsNull();
expressionBuilder.PushNAry(LogicalOperator.Or);
}
ExpressionNode filterPredicate = expressionBuilder.Pop();
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = algebrizedQuery;
filterAlgebraNode.Predicate = filterPredicate;
AlgebraNode input = GetAndResetLastNode();
if (!negated && !ProbingEnabled && input == null)
{
SetLastAlgebraNode(filterAlgebraNode);
return LiteralExpression.FromBoolean(true);
}
else
{
if (input == null)
input = CreateConstantScan();
RowBufferEntry probeColumn = CreateProbeColumn();
JoinAlgebraNode joinAlgebraNode = new JoinAlgebraNode();
joinAlgebraNode.PassthruPredicate = CurrentPassthruPredicate;
joinAlgebraNode.ProbeBufferEntry = probeColumn;
joinAlgebraNode.Left = input;
joinAlgebraNode.Right = filterAlgebraNode;
joinAlgebraNode.Op = negated ? JoinAlgebraNode.JoinOperator.LeftAntiSemiJoin : JoinAlgebraNode.JoinOperator.LeftSemiJoin;
SetLastAlgebraNode(joinAlgebraNode);
return CreateProbeColumnRef(probeColumn);
}
}
public override QueryNode VisitSelectQuery(SelectQuery query)
{
// Calculate needed row buffers
RowBufferCalculator rowBufferCalculator = query.RowBufferCalculator;
// Emit FROM
if (query.TableReferences != null)
{
Visit(query.TableReferences);
}
else
{
ConstantScanAlgebraNode constantScanAlgebraNode = new ConstantScanAlgebraNode();
constantScanAlgebraNode.DefinedValues = new ComputedValueDefinition[0];
SetLastAlgebraNode(constantScanAlgebraNode);
}
// Emit WHERE
if (query.WhereClause != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = query.WhereClause;
SetLastAlgebraNode(filterAlgebraNode);
}
// Emit GROUP BY
if (query.GroupByColumns != null || query.IsAggregated)
{
EmitComputeScalarIfNeeded(rowBufferCalculator.ComputedGroupColumns);
List<AggregatedValueDefinition> definedValues = new List<AggregatedValueDefinition>();
foreach (AggregateExpression aggregateDependency in query.AggregateDependencies)
definedValues.Add(aggregateDependency.ValueDefinition);
if (query.GroupByColumns != null)
{
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.GroupColumns;
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
SetLastAlgebraNode(sortAlgebraNode);
}
AggregateAlgebraNode algebraNode = new AggregateAlgebraNode();
algebraNode.Input = GetLastAlgebraNode();
algebraNode.DefinedValues = definedValues.ToArray();
algebraNode.Groups = rowBufferCalculator.GroupColumns;
SetLastAlgebraNode(algebraNode);
}
// Emit HAVING
if (query.HavingClause != null)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetLastAlgebraNode();
filterAlgebraNode.Predicate = query.HavingClause;
SetLastAlgebraNode(filterAlgebraNode);
}
// Emit compute scalar to calculate expressions needed in SELECT and ORDER BY
EmitComputeScalarIfNeeded(rowBufferCalculator.ComputedSelectAndOrderColumns);
// Emit DISTINCT and ORDER BY
if (query.IsDistinct && query.OrderByColumns != null)
{
List<RowBufferEntry> sortEntries = new List<RowBufferEntry>();
List<SortOrder> sortOrderList = new List<SortOrder>();
for (int i = 0; i < query.OrderByColumns.Length; i++)
{
sortEntries.Add(rowBufferCalculator.OrderColumns[i]);
sortOrderList.Add(query.OrderByColumns[i].SortOrder);
}
foreach (RowBufferEntry selectColumn in rowBufferCalculator.SelectColumns)
{
bool selectColumnMustBeSorted = !sortEntries.Contains(selectColumn);
if (selectColumnMustBeSorted)
{
sortEntries.Add(selectColumn);
sortOrderList.Add(SortOrder.Ascending);
}
}
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = sortEntries.ToArray();
sortAlgebraNode.SortOrders = sortOrderList.ToArray();
SetLastAlgebraNode(sortAlgebraNode);
}
else
{
if (query.IsDistinct)
{
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.SelectColumns;
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
SetLastAlgebraNode(sortAlgebraNode);
}
if (query.OrderByColumns != null)
{
List<SortOrder> sortOrderList = new List<SortOrder>();
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
sortOrderList.Add(orderByColumn.SortOrder);
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = rowBufferCalculator.OrderColumns;
sortAlgebraNode.SortOrders = sortOrderList.ToArray();
SetLastAlgebraNode(sortAlgebraNode);
}
}
// Emit TOP
if (query.TopClause != null)
{
TopAlgebraNode algebraNode = new TopAlgebraNode();
algebraNode.Input = GetLastAlgebraNode();
algebraNode.Limit = query.TopClause.Value;
if (query.TopClause.WithTies)
algebraNode.TieEntries = rowBufferCalculator.OrderColumns;
SetLastAlgebraNode(algebraNode);
}
// Emit select list
List<string> columnNames = new List<string>();
foreach (SelectColumn columnSource in query.SelectColumns)
{
if (columnSource.Alias != null)
columnNames.Add(columnSource.Alias.Text);
else
columnNames.Add(null);
}
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = GetLastAlgebraNode();
resultAlgebraNode.OutputList = rowBufferCalculator.SelectColumns;
resultAlgebraNode.ColumnNames = columnNames.ToArray();
SetLastAlgebraNode(resultAlgebraNode);
return query;
}
private AlgebraNode PushOverValueDefininingUnary(IEnumerable<ValueDefinition> definedValues, FilterAlgebraNode node)
{
UnaryAlgebraNode inputNode = (UnaryAlgebraNode)node.Input;
List<ExpressionNode> nonDependingAndParts = new List<ExpressionNode>();
List<ExpressionNode> dependingAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
RowBufferEntry[] rowBufferEntries = AstUtil.GetRowBufferEntryReferences(andPart);
bool dependsOnDefinedValue = false;
foreach (ValueDefinition definedValue in definedValues)
{
if (ArrayHelpers.Contains(rowBufferEntries, definedValue.Target))
{
dependsOnDefinedValue = true;
break;
}
}
if (dependsOnDefinedValue)
dependingAndParts.Add(andPart);
else
nonDependingAndParts.Add(andPart);
}
if (nonDependingAndParts.Count > 0)
{
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, dependingAndParts);
inputNode.Input = GetFilterFromAndParts(nonDependingAndParts, inputNode.Input);
if (node.Predicate == null)
{
node.Input = inputNode.Input;
inputNode.Input = VisitAlgebraNode(node);
return inputNode;
}
}
node.Input = VisitAlgebraNode(node.Input);
return node;
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
if (node.Predicate == null || !AstUtil.ContainsSubselect(node.Predicate))
{
return(base.VisitJoinAlgebraNode(node));
}
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
switch (node.Op)
{
case JoinAlgebraNode.JoinOperator.InnerJoin:
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = node.Predicate;
filterAlgebraNode.Input = node;
node.Predicate = null;
SetLastAlgebraNode(node);
_probingEnabledStack.Push(false);
filterAlgebraNode.Predicate = VisitExpression(filterAlgebraNode.Predicate);
_probingEnabledStack.Pop();
filterAlgebraNode.Input = GetAndResetLastNode();
return(filterAlgebraNode);
}
case JoinAlgebraNode.JoinOperator.LeftOuterJoin:
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = node.Predicate;
filterAlgebraNode.Input = node.Right;
node.Right = filterAlgebraNode;
node.Predicate = null;
SetLastAlgebraNode(filterAlgebraNode.Input);
_probingEnabledStack.Push(false);
filterAlgebraNode.Predicate = VisitExpression(filterAlgebraNode.Predicate);
_probingEnabledStack.Pop();
filterAlgebraNode.Input = GetAndResetLastNode();
return(node);
}
case JoinAlgebraNode.JoinOperator.RightOuterJoin:
{
node.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
AlgebraNode oldLeft = node.Left;
node.Left = node.Right;
node.Right = oldLeft;
goto case JoinAlgebraNode.JoinOperator.LeftOuterJoin;
}
case JoinAlgebraNode.JoinOperator.FullOuterJoin:
// TODO: Support subqueries in FULL OUTER JOIN.
throw ExceptionBuilder.InternalError("FULL OUTER JOIN containing a subselect predicate in ON clause is not supported.");
default:
throw ExceptionBuilder.UnhandledCaseLabel(node.Op);
}
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
node.OutputList = node.Input.OutputList;
return node;
}
public override ExpressionNode VisitAllAnySubselect(AllAnySubselect expression)
{
expression.Left = VisitExpression(expression.Left);
ResultAlgebraNode algebrizedQuery = Algebrizer.Convert(expression.Query);
ExpressionNode leftExpression = expression.Left;
RowBufferEntryExpression rightExpression = new RowBufferEntryExpression();
rightExpression.RowBufferEntry = algebrizedQuery.OutputList[0];
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(leftExpression);
expressionBuilder.Push(rightExpression);
expressionBuilder.PushBinary(expression.Op);
bool negated = (expression.Type == AllAnySubselect.AllAnyType.All);
if (negated)
{
expressionBuilder.PushUnary(UnaryOperator.LogicalNot);
expressionBuilder.Push(leftExpression);
expressionBuilder.PushIsNull();
expressionBuilder.Push(rightExpression);
expressionBuilder.PushIsNull();
expressionBuilder.PushNAry(LogicalOperator.Or);
}
ExpressionNode filterPredicate = expressionBuilder.Pop();
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = algebrizedQuery;
filterAlgebraNode.Predicate = filterPredicate;
AlgebraNode input = GetAndResetLastNode();
if (!negated && !ProbingEnabled && input == null)
{
SetLastAlgebraNode(filterAlgebraNode);
return(LiteralExpression.FromBoolean(true));
}
else
{
if (input == null)
{
input = CreateConstantScan();
}
RowBufferEntry probeColumn = CreateProbeColumn();
JoinAlgebraNode joinAlgebraNode = new JoinAlgebraNode();
joinAlgebraNode.PassthruPredicate = CurrentPassthruPredicate;
joinAlgebraNode.ProbeBufferEntry = probeColumn;
joinAlgebraNode.Left = input;
joinAlgebraNode.Right = filterAlgebraNode;
joinAlgebraNode.Op = negated ? JoinAlgebraNode.JoinOperator.LeftAntiSemiJoin : JoinAlgebraNode.JoinOperator.LeftSemiJoin;
SetLastAlgebraNode(joinAlgebraNode);
return(CreateProbeColumnRef(probeColumn));
}
}
private static FilterAlgebraNode GetFilterFromAndParts(IList<ExpressionNode> andParts, AlgebraNode input)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = input;
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, andParts);
return filterAlgebraNode;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
Visit(node.Input);
_filters.Add(node.Predicate);
return(node);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
node.OutputList = node.Input.OutputList;
return(node);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
_xmlWriter.WriteStartElement("filterAlgebraNode");
WriteAstNode("input", node.Input);
WriteAstNode("predicate", node.Predicate);
_xmlWriter.WriteEndElement();
return node;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
Visit(node.Input);
_filters.Add(node.Predicate);
return node;
}
public override ExpressionNode VisitBinaryExpression(BinaryExpression expression)
{
if (expression.Op != BinaryOperator.LogicalAnd &&
expression.Op != BinaryOperator.LogicalOr)
return base.VisitBinaryExpression(expression);
if (expression.Op == BinaryOperator.LogicalAnd)
{
// AND
expression.Left = VisitExpression(expression.Left);
expression.Right = VisitExpression(expression.Right);
return expression;
}
else
{
// OR
AlgebraNode input = GetAndResetLastNode();
_probingEnabledStack.Push(false);
List<ExpressionNode> scalarOrParts = new List<ExpressionNode>();
List<AlgebraNode> algebrizedOrParts = new List<AlgebraNode>();
foreach (ExpressionNode orPart in AstUtil.SplitCondition(LogicalOperator.Or, expression))
{
if (!AstUtil.ContainsSubselect(orPart))
{
scalarOrParts.Add(orPart);
}
else
{
ExpressionNode replacedOrPart = VisitExpression(orPart);
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = GetAndResetLastNode();
filterAlgebraNode.Predicate = replacedOrPart;
algebrizedOrParts.Add(filterAlgebraNode);
}
}
if (scalarOrParts.Count > 0)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.Or, scalarOrParts);
filterAlgebraNode.Input = CreateConstantScan();
algebrizedOrParts.Insert(0, filterAlgebraNode);
}
_probingEnabledStack.Pop();
ConcatAlgebraNode concat = new ConcatAlgebraNode();
concat.DefinedValues = new UnitedValueDefinition[0];
concat.Inputs = algebrizedOrParts.ToArray();
RowBufferEntry probeColumn = CreateProbeColumn();
JoinAlgebraNode leftSemiJoinBetweenInputAndConcat = new JoinAlgebraNode();
leftSemiJoinBetweenInputAndConcat.Op = JoinAlgebraNode.JoinOperator.LeftSemiJoin;
leftSemiJoinBetweenInputAndConcat.PassthruPredicate = CurrentPassthruPredicate;
leftSemiJoinBetweenInputAndConcat.ProbeBufferEntry = probeColumn;
leftSemiJoinBetweenInputAndConcat.Left = input;
leftSemiJoinBetweenInputAndConcat.Right = concat;
SetLastAlgebraNode(leftSemiJoinBetweenInputAndConcat);
return CreateProbeColumnRef(probeColumn);
}
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
// Get defined values of left and right
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(node.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(node.Right);
List <ExpressionNode> andPartsWithinJoin = new List <ExpressionNode>();
// Try to pull up AND-parts that contain outer references from a left sided filter and combine
// them with the join predicate.
//
// NOTE: This is only possible if the join is not a LEFT OUTER or FULL OUTER JOIN since this
// operation would change the join's semantic.
if (node.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
FilterAlgebraNode leftAsFilter = node.Left as FilterAlgebraNode;
if (leftAsFilter != null)
{
List <ExpressionNode> remainingAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, leftAsFilter.Predicate))
{
if (AndPartHasOuterReference(andPart, leftDefinedValues))
{
andPartsWithinJoin.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
leftAsFilter.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (leftAsFilter.Predicate == null)
{
node.Left = leftAsFilter.Input;
}
}
}
// Try to pull up AND-parts that contain outer references from a right sided filter and combine
// them with the join predicate.
//
// NOTE: This is only possible if the join is not a RIGHT OUTER or FULL OUTER JOIN since this
// operation would change the join's semantic.
if (node.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin)
{
FilterAlgebraNode rightAsFilter = node.Right as FilterAlgebraNode;
if (rightAsFilter != null)
{
List <ExpressionNode> remainingAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, rightAsFilter.Predicate))
{
if (AndPartHasOuterReference(andPart, rightDefinedValues))
{
andPartsWithinJoin.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
rightAsFilter.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (rightAsFilter.Predicate == null)
{
node.Right = rightAsFilter.Input;
}
}
}
// If we found any AND-parts that could be pulled up, merge them with the join predicate.
if (andPartsWithinJoin.Count > 0)
{
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, node.Predicate, AstUtil.CombineConditions(LogicalOperator.And, andPartsWithinJoin));
}
// Now we try to extract AND-parts that contain outer references from the join predicate itself.
//
// NOTE: This is only possible if the node is not an OUTER JOIN. If the node is a SEMI JOIN the
// operation is only legal if the AND-part does not reference any columns from the side that is
// is used as filter criteria (i.e. for LSJ this is the right side, for RSJ this is the left
// side).
if (node.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
node.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin &&
node.Predicate != null)
{
List <ExpressionNode> andPartsAboveJoin = new List <ExpressionNode>();
List <ExpressionNode> remainingAndParts = new List <ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
if (AndPartHasOuterReference(andPart, leftDefinedValues, rightDefinedValues) &&
SemiJoinDoesNotDependOn(node.Op, andPart, leftDefinedValues, rightDefinedValues))
{
andPartsAboveJoin.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (andPartsAboveJoin.Count > 0)
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, andPartsAboveJoin);
filterAlgebraNode.Input = node;
return(filterAlgebraNode);
}
}
return(node);
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
if (node.Predicate == null || !AstUtil.ContainsSubselect(node.Predicate))
return base.VisitJoinAlgebraNode(node);
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
switch (node.Op)
{
case JoinAlgebraNode.JoinOperator.InnerJoin:
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = node.Predicate;
filterAlgebraNode.Input = node;
node.Predicate = null;
SetLastAlgebraNode(node);
_probingEnabledStack.Push(false);
filterAlgebraNode.Predicate = VisitExpression(filterAlgebraNode.Predicate);
_probingEnabledStack.Pop();
filterAlgebraNode.Input = GetAndResetLastNode();
return filterAlgebraNode;
}
case JoinAlgebraNode.JoinOperator.LeftOuterJoin:
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Predicate = node.Predicate;
filterAlgebraNode.Input = node.Right;
node.Right = filterAlgebraNode;
node.Predicate = null;
SetLastAlgebraNode(filterAlgebraNode.Input);
_probingEnabledStack.Push(false);
filterAlgebraNode.Predicate = VisitExpression(filterAlgebraNode.Predicate);
_probingEnabledStack.Pop();
filterAlgebraNode.Input = GetAndResetLastNode();
return node;
}
case JoinAlgebraNode.JoinOperator.RightOuterJoin:
{
node.Op = JoinAlgebraNode.JoinOperator.LeftOuterJoin;
AlgebraNode oldLeft = node.Left;
node.Left = node.Right;
node.Right = oldLeft;
goto case JoinAlgebraNode.JoinOperator.LeftOuterJoin;
}
case JoinAlgebraNode.JoinOperator.FullOuterJoin:
// TODO: Support subqueries in FULL OUTER JOIN.
throw ExceptionBuilder.InternalError("FULL OUTER JOIN containing a subselect predicate in ON clause is not supported.");
default:
throw ExceptionBuilder.UnhandledCaseLabel(node.Op);
}
}
private AlgebraNode MergeWithFilter(FilterAlgebraNode node)
{
// The input is also a filter, so we can merge this predicate with
// the input filter.
FilterAlgebraNode inputNode = (FilterAlgebraNode) node.Input;
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, node.Predicate);
return VisitAlgebraNode(inputNode);
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
node.Input = VisitAlgebraNode(node.Input);
ConstantExpression predicateAsConstant = node.Predicate as ConstantExpression;
if (predicateAsConstant != null)
{
if (predicateAsConstant.AsBoolean)
return node.Input;
else
return CreateNullScan(node.OutputList);
}
return NullScanIfInputIsNullScan(node);
}
private AlgebraNode PushOverAggregate(FilterAlgebraNode node)
{
// TODO: It is not that easy.
// For example this condition can be pushed 'GroupCol = Value' while this can't: 'GroupCol = Value OR Func(const) = const'
// Formally, a predicate can be pushed over an aggregate if and only if all disjuncts of the predicate's CNF do reference
// at least one grouping column.
// Since this requires cloning of the predicate and heavy rewriting this is not done (yet).
return base.VisitFilterAlgebraNode(node);
/*
// Predicates can be pushed over an aggregation if it does not contain any aggregate function.
AggregateAlgebraNode inputNode = (AggregateAlgebraNode)node.Input;
return PushOverValueDefininingUnary(inputNode.DefinedValues, node);
*/
}
private AlgebraNode PushOverComputeScalar(FilterAlgebraNode node)
{
// Predicates can be pushed over a compute scalar if it does not contain any row buffer entries
// that are defined by the compute scalar node.
ComputeScalarAlgebraNode inputNode = (ComputeScalarAlgebraNode) node.Input;
return PushOverValueDefininingUnary(inputNode.DefinedValues, node);
}
private AlgebraNode PushOverConcat(FilterAlgebraNode node)
{
ConcatAlgebraNode inputNode = (ConcatAlgebraNode) node.Input;
for (int i = 0; i < inputNode.Inputs.Length; i++)
{
ExpressionNode predicate = (ExpressionNode)node.Predicate.Clone();
ConcatRowBufferEntryReplacer concatRowBufferEntryReplacer = new ConcatRowBufferEntryReplacer(inputNode.DefinedValues, i);
predicate = concatRowBufferEntryReplacer.VisitExpression(predicate);
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = inputNode.Inputs[i];
filterAlgebraNode.Predicate = predicate;
inputNode.Inputs[i] = VisitAlgebraNode(filterAlgebraNode);
}
return inputNode;
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
FilterIterator filterIterator = new FilterIterator();
filterIterator.RowBuffer = new object[node.OutputList.Length];
filterIterator.Input = ConvertAlgebraNode(node.Input);
filterIterator.InputOutput = GetIteratorOutput(0, node.Input.OutputList, node.OutputList);
BoundRowBufferEntrySet boundRowBufferEntrySet = new BoundRowBufferEntrySet(filterIterator.Input.RowBuffer, node.Input.OutputList);
filterIterator.Predicate = CreateRuntimeExpression(node.Predicate, boundRowBufferEntrySet);
SetLastIterator(node, filterIterator);
return node;
}
private AlgebraNode PushOverJoin(FilterAlgebraNode node)
{
JoinAlgebraNode inputNode = (JoinAlgebraNode) node.Input;
// Get declared tables of left and right
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(inputNode.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(inputNode.Right);
// Obviously, we cannot merge the filter with the join if the join is an outer join
// (since it would change the join's semantics).
//
// Another less obvious restriction is that we cannot merge a filter with the join if
// the join has a passthru predicate. In case the passthru predicte evaluates to true
// the filter would not be applied. However, we are allowed to push the filter the over
// join.
bool canMerge = inputNode.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin &&
inputNode.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
inputNode.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
inputNode.PassthruPredicate == null;
if (canMerge)
{
// We can merge the filter with the condition of the join.
//
// However, we have to make sure that the predicate does not reference the probe column.
// Since not having a probe column is the most common case, we don't always split the
// predicate into conjuncts.
if (inputNode.ProbeBufferEntry == null || !ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(node.Predicate), inputNode.ProbeBufferEntry))
{
// Either there is no probe column defined or the filter does not reference it. That means
// no splitting necessary, we can just merge the whole predicate with the join predicate.
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, node.Predicate);
return VisitAlgebraNode(inputNode);
}
else
{
// Unfortunately, the filter references the probe column. Now let's check whether we can merge
// conjuncts of the predicate.
List<ExpressionNode> remainingAndParts = new List<ExpressionNode>();
List<ExpressionNode> mergableAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
bool andPartReferencesProbeColumn = ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(andPart), inputNode.ProbeBufferEntry);
if (andPartReferencesProbeColumn)
remainingAndParts.Add(andPart);
else
mergableAndParts.Add(andPart);
}
if (mergableAndParts.Count > 0)
{
ExpressionNode combinedMergableAndParts = AstUtil.CombineConditions(LogicalOperator.And, mergableAndParts.ToArray());
inputNode.Predicate = AstUtil.CombineConditions(LogicalOperator.And, inputNode.Predicate, combinedMergableAndParts);
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (node.Predicate == null)
return VisitAlgebraNode(inputNode);
}
}
}
else
{
// The condition cannot be merged. Now we try to push AND-parts over the join.
List<ExpressionNode> leftAndParts = new List<ExpressionNode>();
List<ExpressionNode> rightAndParts = new List<ExpressionNode>();
List<ExpressionNode> remainingAndParts = new List<ExpressionNode>();
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, node.Predicate))
{
bool andPartReferencesProbeColumn = inputNode.ProbeBufferEntry != null &&
ArrayHelpers.Contains(AstUtil.GetRowBufferEntryReferences(andPart), inputNode.ProbeBufferEntry);
if (!andPartReferencesProbeColumn && AstUtil.AllowsLeftPushOver(inputNode.Op) && AstUtil.ExpressionDoesNotReference(andPart, rightDefinedValues))
{
// The AND-part depends only on the LHS and the join is inner/left.
// So we are allowed to push this AND-part down.
leftAndParts.Add(andPart);
}
else if (!andPartReferencesProbeColumn && AstUtil.AllowsRightPushOver(inputNode.Op) && AstUtil.ExpressionDoesNotReference(andPart, leftDefinedValues))
{
// The AND-part depends only on the RHS and the join is inner/right.
// So we are allowed to push this AND-part down.
rightAndParts.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
if (leftAndParts.Count > 0)
{
inputNode.Left = GetFilterFromAndParts(leftAndParts, inputNode.Left);
}
if (rightAndParts.Count > 0)
{
inputNode.Right = GetFilterFromAndParts(rightAndParts, inputNode.Right);
}
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
if (node.Predicate == null)
return VisitAlgebraNode(inputNode);
}
node.Input = VisitAlgebraNode(node.Input);
return node;
}
public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
// Check if node only consists of INNER join nodes and simple table reference nodes.
// This algorithm assumes that the table references have been lineraized so that
//
// - JoinedTableReference appear on the LHS only (the last one must be NamedTableReference ovbiviously)
// - NamedTableReference appear on the RHS only
//
// While scanning the node's children we create a list of all JoinedTableReferences and
// NamedTableReferences.
InnerJoinTableExtractor innerJoinTableExtractor = new InnerJoinTableExtractor();
innerJoinTableExtractor.Visit(node);
if (!innerJoinTableExtractor.ConsistsOnlyOfInnerJoinsFiltersAndTables)
{
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
return(node);
}
else
{
TableAlgebraNode[] algebraNodes = innerJoinTableExtractor.GetTableNodes();
Dictionary <TableRefBinding, TableAlgebraNode> tableRefToNodeDictionary = new Dictionary <TableRefBinding, TableAlgebraNode>();
List <TableRefBinding> tableList = new List <TableRefBinding>();
foreach (TableAlgebraNode algebraNode in algebraNodes)
{
tableRefToNodeDictionary.Add(algebraNode.TableRefBinding, algebraNode);
tableList.Add(algebraNode.TableRefBinding);
}
// Create a mapping RowBufferEntry -> ColumnRefBinding
Dictionary <RowBufferEntry, ColumnRefBinding> rowBufferColumnDictionary = new Dictionary <RowBufferEntry, ColumnRefBinding>();
foreach (TableRefBinding tableRefBinding in tableList)
{
foreach (ColumnRefBinding columnRefBinding in tableRefBinding.ColumnRefs)
{
rowBufferColumnDictionary.Add(columnRefBinding.ValueDefinition.Target, columnRefBinding);
}
}
// Create list of all possible join conditions and remaining AND-parts.
List <JoinCondition> joinConditionList = new List <JoinCondition>();
List <ExpressionNode> andPartList = new List <ExpressionNode>();
ExpressionNode filter = AstUtil.CombineConditions(LogicalOperator.And, innerJoinTableExtractor.GetFilters());
foreach (ExpressionNode andPart in AstUtil.SplitCondition(LogicalOperator.And, filter))
{
JoinCondition joinCondition = ConvertToJoinCondition(rowBufferColumnDictionary, andPart);
if (joinCondition != null)
{
joinConditionList.Add(joinCondition);
}
else
{
andPartList.Add(andPart);
}
}
// After creating the list of all join conditions and AND-parts we have all we need to create
// an optimimal join order between all tables of this part of the table tree.
JoinOrder bestJoinOrder = GetBestJoinOrder(tableList.ToArray(), joinConditionList.ToArray(), andPartList.ToArray());
// Get all tables that are introduced by this join order
Dictionary <RowBufferEntry, ColumnValueDefinition> introducedColumns = GetIntroducedColumns(bestJoinOrder);
// Combine AND-part list with all unused join conditions.
andPartList.AddRange(bestJoinOrder.UnusedConditions);
// Now we will re-create this part of the tree using the this join order.
AlgebraNode lastAlgebraNode = null;
for (int joinIndex = 0; joinIndex < bestJoinOrder.Joins.Length; joinIndex++)
{
Join join = bestJoinOrder.Joins[joinIndex];
AlgebraNode tableInput;
TableAlgebraNode tableNode = tableRefToNodeDictionary[join.TableRefBinding];
ExpressionNode tableFilter = ExtractConditionsApplicableToTable(introducedColumns, andPartList, join.TableRefBinding);
if (tableFilter == null)
{
tableInput = tableNode;
}
else
{
FilterAlgebraNode filterAlgebraNode = new FilterAlgebraNode();
filterAlgebraNode.Input = tableNode;
filterAlgebraNode.Predicate = tableFilter;
tableInput = filterAlgebraNode;
}
if (lastAlgebraNode == null)
{
// This was the first one.
lastAlgebraNode = tableInput;
}
else
{
// Not the first one, we can create a join with the current table reference
// and last table reference.
// Get all AND-parts that can be applied to the tables already joined.
// This expression is merged to one condition.
ExpressionNode[] applicableAndParts = GetAndPartsApplicableToJoin(introducedColumns, bestJoinOrder, joinIndex, andPartList, true);
ExpressionNode condition = AstUtil.CombineConditions(LogicalOperator.And, applicableAndParts);
ExpressionNode joinCondition;
if (join.JoinCondition == null)
{
joinCondition = null;
}
else
{
joinCondition = join.JoinCondition.ToExpression();
}
ExpressionNode completeCondition = AstUtil.CombineConditions(LogicalOperator.And, condition, joinCondition);
JoinAlgebraNode joinAlgebraNode = new JoinAlgebraNode();
joinAlgebraNode.Op = JoinAlgebraNode.JoinOperator.InnerJoin;
joinAlgebraNode.Left = lastAlgebraNode;
joinAlgebraNode.Right = tableInput;
joinAlgebraNode.Predicate = completeCondition;
// Next time this newly created join is the last table reference.
lastAlgebraNode = joinAlgebraNode;
}
}
return(lastAlgebraNode);
}
}
public override AlgebraNode VisitFilterAlgebraNode(FilterAlgebraNode node)
{
ShowPlanElement inputElement = ConvertNode(node.Input);
PropertyListBuilder propertyListBuilder = new PropertyListBuilder();
AddRowBufferEntries(propertyListBuilder, Resources.ShowPlanGroupOutputList, node.OutputList);
AddStatistics(propertyListBuilder, node.StatisticsIterator);
propertyListBuilder.Write(Resources.ShowPlanKeyPredicate, node.Predicate.GenerateSource());
IList<ShowPlanProperty> properties = propertyListBuilder.ToList();
ShowPlanElement element = new ShowPlanElement(ShowPlanOperator.Filter, properties, inputElement);
_currentElement = element;
return node;
}
