diff options
Diffstat (limited to 'src/backend/optimizer/plan/initsplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index 904f710d593..2b2c6af9ef8 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -1540,7 +1540,8 @@ make_outerjoininfo(PlannerInfo *root, } else if (jointype == JOIN_LEFT && otherinfo->jointype == JOIN_LEFT && - bms_overlap(strict_relids, otherinfo->min_righthand)) + bms_overlap(strict_relids, otherinfo->min_righthand) && + !bms_overlap(clause_relids, otherinfo->syn_lefthand)) { /* Identity 3 applies, so remove the ordering restriction */ min_lefthand = bms_del_member(min_lefthand, otherinfo->ojrelid); @@ -1985,12 +1986,18 @@ deconstruct_distribute_oj_quals(PlannerInfo *root, /* * When we are looking at joins above sjinfo, we are envisioning * pushing sjinfo to above othersj, so add othersj's nulling bit - * before distributing the quals. + * before distributing the quals. We should add it to Vars coming + * from the current join's LHS: we want to transform the second + * form of OJ identity 3 to the first form, in which Vars of + * relation B will appear nulled by the syntactically-upper OJ + * within the Pbc clause, but those of relation C will not. (In + * the notation used by optimizer/README, we're converting a qual + * of the form Pbc to Pb*c.) */ if (above_sjinfo) quals = (List *) add_nulling_relids((Node *) quals, - othersj->min_righthand, + sjinfo->syn_lefthand, bms_make_singleton(othersj->ojrelid)); /* Compute qualscope and ojscope for this join level */ @@ -2041,12 +2048,16 @@ deconstruct_distribute_oj_quals(PlannerInfo *root, /* * Adjust qual nulling bits for next level up, if needed. We * don't want to put sjinfo's own bit in at all, and if we're - * above sjinfo then we did it already. + * above sjinfo then we did it already. Here, we should mark all + * Vars coming from the lower join's RHS. (Again, we are + * converting a qual of the form Pbc to Pb*c, but now we are + * putting back bits that were there in the parser output and were + * temporarily stripped above.) */ if (below_sjinfo) quals = (List *) add_nulling_relids((Node *) quals, - othersj->min_righthand, + othersj->syn_righthand, bms_make_singleton(othersj->ojrelid)); /* ... and track joins processed so far */ |