diff options
Diffstat (limited to 'src/backend/optimizer/plan/analyzejoins.c')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 42da62c1c6b..1ca554a6430 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -164,6 +164,7 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) { int innerrelid; RelOptInfo *innerrel; + Relids inputrelids; Relids joinrelids; List *clause_list = NIL; ListCell *l; @@ -190,17 +191,16 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) return false; /* Compute the relid set for the join we are considering */ - joinrelids = bms_union(sjinfo->min_lefthand, sjinfo->min_righthand); - if (sjinfo->ojrelid != 0) - joinrelids = bms_add_member(joinrelids, sjinfo->ojrelid); + inputrelids = bms_union(sjinfo->min_lefthand, sjinfo->min_righthand); + Assert(sjinfo->ojrelid != 0); + joinrelids = bms_copy(inputrelids); + joinrelids = bms_add_member(joinrelids, sjinfo->ojrelid); /* * We can't remove the join if any inner-rel attributes are used above the - * join. - * - * Note that this test only detects use of inner-rel attributes in higher - * join conditions and the target list. There might be such attributes in - * pushed-down conditions at this join, too. We check that case below. + * join. Here, "above" the join includes pushed-down conditions, so we + * should reject if attr_needed includes the OJ's own relid; therefore, + * compare to inputrelids not joinrelids. * * As a micro-optimization, it seems better to start with max_attr and * count down rather than starting with min_attr and counting up, on the @@ -211,7 +211,7 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) attroff >= 0; attroff--) { - if (!bms_is_subset(innerrel->attr_needed[attroff], joinrelids)) + if (!bms_is_subset(innerrel->attr_needed[attroff], inputrelids)) return false; } @@ -230,7 +230,7 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) if (bms_overlap(phinfo->ph_lateral, innerrel->relids)) return false; /* it references innerrel laterally */ - if (bms_is_subset(phinfo->ph_needed, joinrelids)) + if (bms_is_subset(phinfo->ph_needed, inputrelids)) continue; /* PHV is not used above the join */ if (!bms_overlap(phinfo->ph_eval_at, innerrel->relids)) continue; /* it definitely doesn't reference innerrel */ @@ -273,13 +273,11 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo) { /* * If such a clause actually references the inner rel then join - * removal has to be disallowed. We have to check this despite - * the previous attr_needed checks because of the possibility of - * pushed-down clauses referencing the rel. + * removal has to be disallowed. The previous attr_needed checks + * should have caught this, though. */ - if (bms_is_member(innerrelid, restrictinfo->clause_relids)) - return false; - continue; /* else, ignore; not useful here */ + Assert(!bms_is_member(innerrelid, restrictinfo->clause_relids)); + continue; /* ignore; not useful here */ } /* Ignore if it's not a mergejoinable clause */ |