private AlgebraNode PushOverJoin(ComputeScalarAlgebraNode node)
{
JoinAlgebraNode joinAlgebraNode = (JoinAlgebraNode)node.Input;
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(joinAlgebraNode.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(joinAlgebraNode.Right);
List <ComputedValueDefinition> remainingValueDefinitions = new List <ComputedValueDefinition>();
List <ComputedValueDefinition> leftPushedValueDefinitions = new List <ComputedValueDefinition>();
List <ComputedValueDefinition> rightPushedValueDefinitions = new List <ComputedValueDefinition>();
bool canPushToLeftSide = joinAlgebraNode.Op != JoinAlgebraNode.JoinOperator.RightOuterJoin &&
joinAlgebraNode.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin;
bool canPushToRightSide = joinAlgebraNode.Op != JoinAlgebraNode.JoinOperator.LeftOuterJoin &&
joinAlgebraNode.Op != JoinAlgebraNode.JoinOperator.FullOuterJoin;
foreach (ComputedValueDefinition valueDefinition in node.DefinedValues)
{
RowBufferEntry[] referencedValues = AstUtil.GetRowBufferEntryReferences(valueDefinition.Expression);
bool referencesProbeColumn = ArrayHelpers.Contains(referencedValues, joinAlgebraNode.ProbeBufferEntry);
if (!referencesProbeColumn && canPushToLeftSide && AstUtil.DoesNotReference(referencedValues, rightDefinedValues))
{
leftPushedValueDefinitions.Add(valueDefinition);
}
else if (!referencesProbeColumn && canPushToRightSide && AstUtil.DoesNotReference(referencedValues, leftDefinedValues))
{
rightPushedValueDefinitions.Add(valueDefinition);
}
else
{
remainingValueDefinitions.Add(valueDefinition);
}
}
if (leftPushedValueDefinitions.Count > 0)
{
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.DefinedValues = leftPushedValueDefinitions.ToArray();
computeScalarAlgebraNode.Input = joinAlgebraNode.Left;
joinAlgebraNode.Left = VisitAlgebraNode(computeScalarAlgebraNode);
}
if (rightPushedValueDefinitions.Count > 0)
{
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.DefinedValues = rightPushedValueDefinitions.ToArray();
computeScalarAlgebraNode.Input = joinAlgebraNode.Right;
joinAlgebraNode.Right = VisitAlgebraNode(computeScalarAlgebraNode);
}
if (remainingValueDefinitions.Count == 0)
{
return(joinAlgebraNode);
}
node.DefinedValues = remainingValueDefinitions.ToArray();
return(node);
}
