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Dept. of second thoughts: clause_selectivity shouldn't try to cache its

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result for jointypes associated with IN processing.
This commit is contained in:
Tom Lane 2004-01-05 16:44:40 +00:00
parent 9091e8d1b2
commit cce442da6d
1 changed files with 29 additions and 8 deletions
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29
src/backend/optimizer/path/clausesel.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.63 2004/01/04 03:51:52 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.64 2004/01/05 16:44:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -417,17 +417,38 @@ clause_selectivity(Query *root,
* If possible, cache the result of the selectivity calculation for
* the clause. We can cache if varRelid is zero or the clause
* contains only vars of that relid --- otherwise varRelid will affect
* the result, so mustn't cache. We ignore the possibility that
* jointype will affect the result, which should be okay because outer
* join clauses will always be examined with the same jointype value.
* the result, so mustn't cache. We also have to be careful about
* the jointype. It's OK to cache when jointype is JOIN_INNER or
* one of the outer join types (any given outer-join clause should
* always be examined with the same jointype, so result won't change).
* It's not OK to cache when jointype is one of the special types
* associated with IN processing, because the same clause may be
* examined with different jointypes and the result should vary.
*/
if (varRelid == 0 ||
bms_is_subset_singleton(rinfo->clause_relids, varRelid))
{
switch (jointype)
{
case JOIN_INNER:
case JOIN_LEFT:
case JOIN_FULL:
case JOIN_RIGHT:
/* Cacheable --- do we already have the result? */
if (rinfo->this_selec >= 0)
return rinfo->this_selec;
cacheable = true;
break;
case JOIN_UNION:
/* unimplemented anyway... */
case JOIN_IN:
case JOIN_REVERSE_IN:
case JOIN_UNIQUE_OUTER:
case JOIN_UNIQUE_INNER:
/* unsafe to cache */
break;
}
}
/* Proceed with examination of contained clause */