Can anyone explain to me how the "ps_OuterTupleSlot" in PlanState is being used in implementing HashJoin?
Hello there,
Can anyone explain to me how the "ps_OuterTupleSlot" in JoinState is being used in implementing HashJoin?
I looked at the source code. When it find a tuple in outer relation. It store the outer tuple to field : node->js.ps.ps_OuterTupleSlot
But I can't find how this field is being used in the following processing.
Thanks,
Ran
Ran Tang <8rt4@queensu.ca> writes:
Can anyone explain to me how the "ps_OuterTupleSlot" in JoinState is being used in implementing HashJoin?
Hmm ... [ sounds of grepping ] actually it looks to me like
PlanState.ps_OuterTupleSlot is entirely dead code now. The thing that
actually does something useful is econtext->ecxt_outertuple, which feeds
into qual-condition-checking and result-tuple-projection via Vars that
have varno=OUTER. But I don't see anyplace that is using the
ps_OuterTupleSlot field.
regards, tom lane