public override AlgebraNode VisitJoinAlgebraNode(JoinAlgebraNode node)
{
// Get declared tables of left and right
RowBufferEntry[] leftDefinedValues = AstUtil.GetDefinedValueEntries(node.Left);
RowBufferEntry[] rightDefinedValues = AstUtil.GetDefinedValueEntries(node.Right);
// Analyze AND-parts of Condition
if (node.Predicate != null)
{
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))
{
// Check if we can push this AND-part down.
if (AstUtil.AllowsLeftPushDown(node.Op) && AstUtil.ExpressionDoesNotReference(andPart, rightDefinedValues))
{
leftAndParts.Add(andPart);
}
else if (AstUtil.AllowsRightPushDown(node.Op) && AstUtil.ExpressionDoesNotReference(andPart, leftDefinedValues))
{
rightAndParts.Add(andPart);
}
else
{
remainingAndParts.Add(andPart);
}
}
if (leftAndParts.Count > 0)
{
node.Left = GetFilterFromAndParts(leftAndParts, node.Left);
}
if (rightAndParts.Count > 0)
{
node.Right = GetFilterFromAndParts(rightAndParts, node.Right);
}
node.Predicate = AstUtil.CombineConditions(LogicalOperator.And, remainingAndParts);
}
// Visit children
node.Left = VisitAlgebraNode(node.Left);
node.Right = VisitAlgebraNode(node.Right);
return(node);
}
