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 QueryNode VisitBinaryQuery(BinaryQuery query)
{
switch (query.Op)
{
case BinaryQueryOperator.Intersect:
case BinaryQueryOperator.Except:
{
ResultAlgebraNode left = ((ResultAlgebraNode)ConvertAstNode(query.Left));
ResultAlgebraNode right = ((ResultAlgebraNode)ConvertAstNode(query.Right));
// Create distinct sort
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = left;
sortAlgebraNode.SortEntries = left.OutputList;
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
// Insert left (anti) semi join to (except) intersect left and right.
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
for (int i = 0; i < left.OutputList.Length; i++)
{
RowBufferEntryExpression leftExpr = new RowBufferEntryExpression();
leftExpr.RowBufferEntry = left.OutputList[i];
RowBufferEntryExpression rightExpr = new RowBufferEntryExpression();
rightExpr.RowBufferEntry = right.OutputList[i];
expressionBuilder.Push(leftExpr);
expressionBuilder.Push(rightExpr);
expressionBuilder.PushBinary(BinaryOperator.Equal);
expressionBuilder.Push(leftExpr);
expressionBuilder.PushIsNull();
expressionBuilder.Push(rightExpr);
expressionBuilder.PushIsNull();
expressionBuilder.PushBinary(BinaryOperator.LogicalAnd);
expressionBuilder.PushBinary(BinaryOperator.LogicalOr);
}
expressionBuilder.PushNAry(LogicalOperator.And);
ExpressionNode joinCondition = expressionBuilder.Pop();
JoinAlgebraNode joinAlgebraNode = new JoinAlgebraNode();
if (query.Op == BinaryQueryOperator.Intersect)
{
joinAlgebraNode.Op = JoinAlgebraNode.JoinOperator.LeftSemiJoin;
}
else
{
joinAlgebraNode.Op = JoinAlgebraNode.JoinOperator.LeftAntiSemiJoin;
}
joinAlgebraNode.Left = sortAlgebraNode;
joinAlgebraNode.Right = right;
joinAlgebraNode.Predicate = joinCondition;
SetLastAlgebraNode(joinAlgebraNode);
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = GetLastAlgebraNode();
resultAlgebraNode.OutputList = left.OutputList;
resultAlgebraNode.ColumnNames = left.ColumnNames;
SetLastAlgebraNode(resultAlgebraNode);
break;
}
case BinaryQueryOperator.Union:
case BinaryQueryOperator.UnionAll:
{
// Build a flat list with all inputs.
List <QueryNode> inputList = AstUtil.FlattenBinaryQuery(query);
AlgebraNode[] inputs = new AlgebraNode[inputList.Count];
for (int i = 0; i < inputs.Length; i++)
{
inputs[i] = ConvertAstNode(inputList[i]);
}
int outputColumnCount = inputs[0].OutputList.Length;
UnitedValueDefinition[] definedValues = new UnitedValueDefinition[outputColumnCount];
List <RowBufferEntry> definedValueEntries = new List <RowBufferEntry>();
for (int i = 0; i < outputColumnCount; i++)
{
RowBufferEntry rowBufferEntry = new RowBufferEntry(inputs[0].OutputList[i].DataType);
definedValueEntries.Add(rowBufferEntry);
UnitedValueDefinition definedValue = new UnitedValueDefinition();
definedValue.Target = rowBufferEntry;
List <RowBufferEntry> dependencies = new List <RowBufferEntry>();
foreach (ResultAlgebraNode node in inputs)
{
dependencies.Add(node.OutputList[i]);
}
definedValue.DependendEntries = dependencies.ToArray();
definedValues[i] = definedValue;
}
ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode();
concatAlgebraNode.Inputs = inputs;
concatAlgebraNode.DefinedValues = definedValues;
SetLastAlgebraNode(concatAlgebraNode);
if (query.Op == BinaryQueryOperator.Union)
{
SortAlgebraNode sortAlgebraNode = new SortAlgebraNode();
sortAlgebraNode.Distinct = true;
sortAlgebraNode.Input = GetLastAlgebraNode();
sortAlgebraNode.SortEntries = definedValueEntries.ToArray();
sortAlgebraNode.SortOrders = CreateAscendingSortOrders(sortAlgebraNode.SortEntries.Length);
SetLastAlgebraNode(sortAlgebraNode);
}
ResultAlgebraNode unionResultAlgebraNode = new ResultAlgebraNode();
unionResultAlgebraNode.Input = GetLastAlgebraNode();
unionResultAlgebraNode.ColumnNames = ((ResultAlgebraNode)inputs[0]).ColumnNames;
unionResultAlgebraNode.OutputList = definedValueEntries.ToArray();
SetLastAlgebraNode(unionResultAlgebraNode);
break;
}
}
return(query);
}
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)
{
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 static ResultAlgebraNode CreateAssertedSubquery(ResultAlgebraNode inputNode)
{
if (AstUtil.WillProduceAtMostOneRow(inputNode))
{
return(inputNode);
}
RowBufferEntry inputEntry = inputNode.OutputList[0];
AggregatedValueDefinition countDefinedValue = new AggregatedValueDefinition();
countDefinedValue.Aggregate = new CountAggregateBinding("COUNT");
countDefinedValue.Aggregator = countDefinedValue.Aggregate.CreateAggregator(typeof(int));
countDefinedValue.Argument = LiteralExpression.FromInt32(0);
RowBufferEntry countDefinedValueEntry = new RowBufferEntry(countDefinedValue.Aggregator.ReturnType);
countDefinedValue.Target = countDefinedValueEntry;
RowBufferEntryExpression anyAggregateArgument = new RowBufferEntryExpression();
anyAggregateArgument.RowBufferEntry = inputEntry;
AggregatedValueDefinition anyDefinedValue = new AggregatedValueDefinition();
anyDefinedValue.Aggregate = new FirstAggregateBinding("ANY");
anyDefinedValue.Aggregator = anyDefinedValue.Aggregate.CreateAggregator(inputEntry.DataType);
anyDefinedValue.Argument = anyAggregateArgument;
RowBufferEntry anyDefinedValueEntry = new RowBufferEntry(inputEntry.DataType);
anyDefinedValue.Target = anyDefinedValueEntry;
AggregateAlgebraNode aggregateAlgebraNode = new AggregateAlgebraNode();
aggregateAlgebraNode.Input = inputNode.Input;
aggregateAlgebraNode.DefinedValues = new AggregatedValueDefinition[] { countDefinedValue, anyDefinedValue };
// CASE WHEN SubqueryCount > 1 THEN 0 ELSE NULL END
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(new RowBufferEntryExpression(countDefinedValueEntry));
expressionBuilder.Push(LiteralExpression.FromInt32(1));
expressionBuilder.PushBinary(BinaryOperator.Greater);
ExpressionNode whenExpression = expressionBuilder.Pop();
ExpressionNode thenExpression = LiteralExpression.FromInt32(0);
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[] { whenExpression };
caseExpression.ThenExpressions = new ExpressionNode[] { thenExpression };
expressionBuilder.Push(caseExpression);
ExpressionNode predicate = expressionBuilder.Pop();
AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode();
assertAlgebraNode.Input = aggregateAlgebraNode;
assertAlgebraNode.Predicate = predicate;
assertAlgebraNode.AssertionType = AssertionType.MaxOneRow;
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = assertAlgebraNode;
resultAlgebraNode.OutputList = new RowBufferEntry[] { anyDefinedValueEntry };
resultAlgebraNode.ColumnNames = inputNode.ColumnNames;
return(resultAlgebraNode);
}
public override QueryNode VisitSelectQuery(SelectQuery query)
{
PushQueryScope(query.QueryScope);
// Validate all embedded AST entries that need to check a query context.
_queryNestingLevel++;
QueryNode result = base.VisitSelectQuery(query);
_queryNestingLevel--;
// Validate DISTINCT
if (query.IsDistinct)
{
// Ensure that all column sources are datatypes that are comparable.
foreach (SelectColumn columnSource in query.SelectColumns)
{
if (!CheckIfTypeIsComparable(columnSource.Expression.ExpressionType))
{
_errorReporter.InvalidDataTypeInSelectDistinct(columnSource.Expression.ExpressionType);
}
}
}
// Validate TOP
if (query.TopClause != null)
{
if (query.TopClause.WithTies && query.OrderByColumns == null)
{
_errorReporter.TopWithTiesRequiresOrderBy();
}
}
// Ensure that all ORDER BY datatypes are comparable.
if (query.OrderByColumns != null)
{
ValidateOrderByClause(query.OrderByColumns);
}
// Ensure that if both DISTINCT and ORDER BY are presents all expressions in ORDER BY are also part in SELECT.
if (query.IsDistinct && query.OrderByColumns != null)
{
bool allColumnsAreInInput = GetAllColumnsAreInInput(query.SelectColumns, query.OrderByColumns);
if (!allColumnsAreInInput)
{
_errorReporter.OrderByItemsMustBeInSelectListIfDistinctSpecified();
}
}
// Validate GROUP BY and aggregation-only queries.
if (query.GroupByColumns == null)
{
if (query.IsAggregated || query.HavingClause != null)
{
// No grouping applied but at least one aggregation function present. That
// means we have an aggregation-only query.
//
// Check that all expressions in SELECT are either aggregated or do not
// reference any column.
foreach (SelectColumn columnSource in query.SelectColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, columnSource.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.SelectExpressionNotAggregatedAndNoGroupBy(referencedColumn);
}
}
}
// Check that all expressions in HAVING are either aggregated or do not
// reference any column.
if (query.HavingClause != null)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, query.HavingClause))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.HavingExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in ORDER BY are either aggregated or do not
// reference any column.
if (query.OrderByColumns != null)
{
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, orderByColumn.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.OrderByExpressionNotAggregatedAndNoGroupBy(referencedColumn);
}
}
}
}
}
}
else
{
// Grouped query:
//
// 1. All expression in GROUP BY must have a datatype that is comparable.
//
// 2. All expressions in GROUP BY must not be aggregated
//
// 3. All expressions in SELECT, ORDER BY, and HAVING must be aggregated, grouped or must not reference
// columns.
// Check that all GROUP BY expressions are not aggregated.
foreach (ExpressionNode groupExpression in query.GroupByColumns)
{
if (!CheckIfTypeIsComparable(groupExpression.ExpressionType))
{
_errorReporter.InvalidDataTypeInGroupBy(groupExpression.ExpressionType);
}
MetaInfo metaInfo = AstUtil.GetMetaInfo(groupExpression);
if (metaInfo.ColumnDependencies.Length == 0)
{
_errorReporter.GroupByItemDoesNotReferenceAnyColumns();
}
}
// Check that all expressions in SELECT are either part of the GROUP BY or are referencing only those
// columns that are part of the GROUP BY.
foreach (SelectColumn columnSource in query.SelectColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, columnSource.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.SelectExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in HAVING are either part of the GROUP BY or are referencing only those
// columns that are part of the GROUP BY.
if (query.HavingClause != null)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, query.HavingClause))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.HavingExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in the ORDER BY clause are either part of the GROUP BY or are
// referencing only those columns that are part of the GROUP BY.
if (query.OrderByColumns != null)
{
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, orderByColumn.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.OrderByExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
}
}
PopQueryScope();
return(result);
}
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)
{
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 ExpressionNode VisitUnaryExpression(UnaryExpression expression)
{
// First visit arguments
base.VisitUnaryExpression(expression);
if (expression.Op == UnaryOperator.LogicalNot)
{
// Replace "NOT NOT expr" by "expr"
UnaryExpression unOp = expression.Operand as UnaryExpression;
if (unOp != null)
{
if (unOp.Op == UnaryOperator.LogicalNot)
{
return(VisitExpression(unOp.Operand));
}
}
// Replace "NOT expr IS NULL" and "NOT expr IS NOT NULL" by
// "expr IS NOT NULL" and "expr IS NULL" resp.
IsNullExpression isNull = expression.Operand as IsNullExpression;
if (isNull != null)
{
isNull.Negated = !isNull.Negated;
return(VisitExpression(isNull));
}
// Apply negation on EXISTS
ExistsSubselect existsSubselect = expression.Operand as ExistsSubselect;
if (existsSubselect != null)
{
existsSubselect.Negated = !existsSubselect.Negated;
return(existsSubselect);
}
// Apply negation on ALL/ANY subquery
AllAnySubselect allAnySubselect = expression.Operand as AllAnySubselect;
if (allAnySubselect != null)
{
allAnySubselect.Op = AstUtil.NegateBinaryOp(allAnySubselect.Op);
allAnySubselect.Type = (allAnySubselect.Type == AllAnySubselect.AllAnyType.All) ? AllAnySubselect.AllAnyType.Any : AllAnySubselect.AllAnyType.All;
return(allAnySubselect);
}
// Apply De Morgan's law
BinaryExpression binOp = expression.Operand as BinaryExpression;
if (binOp != null)
{
BinaryOperator negatedOp = AstUtil.NegateBinaryOp(binOp.Op);
if (negatedOp != null)
{
ExpressionNode newLeft;
ExpressionNode newRight;
if (binOp.Op == BinaryOperator.LogicalAnd || binOp.Op == BinaryOperator.LogicalOr)
{
newLeft = new UnaryExpression(expression.Op, binOp.Left);
newRight = new UnaryExpression(expression.Op, binOp.Right);
}
else
{
newLeft = binOp.Left;
newRight = binOp.Right;
}
binOp.Op = negatedOp;
binOp.Left = newLeft;
binOp.Right = newRight;
return(VisitExpression(binOp));
}
}
}
return(expression);
}
