Re: Can anyone explain to me how the "ps_OuterTupleSlot" in PlanState is being used in implementing HashJoin?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Ran Tang <8rt4(at)queensu(dot)ca>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Can anyone explain to me how the "ps_OuterTupleSlot" in PlanState is being used in implementing HashJoin?
Date: 2008-10-23 05:08:51
Message-ID: 6342.1224738531@sss.pgh.pa.us
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Ran Tang <8rt4(at)queensu(dot)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

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