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IN clauses appearing at top level of WHERE can now be handled as joins.

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There are two implementation techniques: the executor understands a new
JOIN_IN jointype, which emits at most one matching row per left-hand row,
or the result of the IN's sub-select can be fed through a DISTINCT filter
and then joined as an ordinary relation.
Along the way, some minor code cleanup in the optimizer; notably, break
out most of the jointree-rearrangement preprocessing in planner.c and
put it in a new file prep/prepjointree.c.
This commit is contained in:
Tom Lane
2003-01-20 18:55:07 +00:00
parent be2b660ecd
commit bdfbfde1b1
47 changed files with 2075 additions and 875 deletions
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12
src/backend/executor/nodeNestloop.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/nodeNestloop.c,v 1.29 2002/12/15 16:17:46 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/nodeNestloop.c,v 1.30 2003/01/20 18:54:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -101,6 +101,15 @@ ExecNestLoop(NestLoopState *node)
node->js.ps.ps_TupFromTlist = false;
}
/*
* If we're doing an IN join, we want to return at most one row per
* outer tuple; so we can stop scanning the inner scan if we matched on
* the previous try.
*/
if (node->js.jointype == JOIN_IN &&
node->nl_MatchedOuter)
node->nl_NeedNewOuter = true;
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't
@ -312,6 +321,7 @@ ExecInitNestLoop(NestLoop *node, EState *estate)
switch (node->join.jointype)
{
case JOIN_INNER:
case JOIN_IN:
break;
case JOIN_LEFT:
nlstate->nl_NullInnerTupleSlot =