diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2009-02-27 22:41:38 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2009-02-27 22:41:38 +0000 |
| commit | 75c85bd1997f6fba1cb9cdf0fa48fab220b0e745 (patch) | |
| tree | c9bd63c61c01cf4b5b8e517efa929fbba86473cc /src/backend/optimizer/plan/initsplan.c | |
| parent | 5c4ca3b6321794ab95487a6a6ebc23af150bf9e9 (diff) | |
Tighten up join ordering rules to account for recent more-careful analysis
of the associativity of antijoins. Also improve optimizer/README discussion
of outer join ordering rules.
Diffstat (limited to 'src/backend/optimizer/plan/initsplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index 25117716c34..cf05f033b9a 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.148 2009/02/25 03:30:37 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.149 2009/02/27 22:41:38 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -628,26 +628,32 @@ make_outerjoininfo(PlannerInfo *root, * min_lefthand. (We must use its full syntactic relset, not just its * min_lefthand + min_righthand. This is because there might be other * OJs below this one that this one can commute with, but we cannot - * commute with them if we don't with this one.) + * commute with them if we don't with this one.) Also, if the + * current join is an antijoin, we must preserve ordering regardless + * of strictness. * * Note: I believe we have to insist on being strict for at least one * rel in the lower OJ's min_righthand, not its whole syn_righthand. */ - if (bms_overlap(left_rels, otherinfo->syn_righthand) && - bms_overlap(clause_relids, otherinfo->syn_righthand) && - !bms_overlap(strict_relids, otherinfo->min_righthand)) + if (bms_overlap(left_rels, otherinfo->syn_righthand)) { - min_lefthand = bms_add_members(min_lefthand, - otherinfo->syn_lefthand); - min_lefthand = bms_add_members(min_lefthand, - otherinfo->syn_righthand); + if (bms_overlap(clause_relids, otherinfo->syn_righthand) && + (jointype == JOIN_ANTI || + !bms_overlap(strict_relids, otherinfo->min_righthand))) + { + min_lefthand = bms_add_members(min_lefthand, + otherinfo->syn_lefthand); + min_lefthand = bms_add_members(min_lefthand, + otherinfo->syn_righthand); + } } /* * For a lower OJ in our RHS, if our join condition does not use the * lower join's RHS and the lower OJ's join condition is strict, we * can interchange the ordering of the two OJs; otherwise we must add - * lower OJ's full syntactic relset to min_righthand. + * lower OJ's full syntactic relset to min_righthand. Here, we must + * preserve ordering anyway if the lower OJ is an antijoin. * * Here, we have to consider that "our join condition" includes any * clauses that syntactically appeared above the lower OJ and below @@ -663,6 +669,7 @@ make_outerjoininfo(PlannerInfo *root, if (bms_overlap(right_rels, otherinfo->syn_righthand)) { if (bms_overlap(clause_relids, otherinfo->syn_righthand) || + otherinfo->jointype == JOIN_ANTI || !otherinfo->lhs_strict || otherinfo->delay_upper_joins) { min_righthand = bms_add_members(min_righthand, |