diff options
Diffstat (limited to 'src/backend/optimizer/plan/analyzejoins.c')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index fb01fbe357a..1fb17ee29f2 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -1247,8 +1247,10 @@ innerrel_is_unique(PlannerInfo *root, /* * innerrel_is_unique_ext - * Do the same as innerrel_is_unique(), but also return additional clauses - * from a baserestrictinfo list that were used to prove uniqueness. + * Do the same as innerrel_is_unique(), but also set to '*extra_clauses' + * additional clauses from a baserestrictinfo list that were used to prove + * uniqueness. A non NULL 'extra_clauses' indicates that we're checking + * for self-join and correspondingly dealing with filtered clauses. */ bool innerrel_is_unique_ext(PlannerInfo *root, @@ -1264,6 +1266,7 @@ innerrel_is_unique_ext(PlannerInfo *root, ListCell *lc; UniqueRelInfo *uniqueRelInfo; List *outer_exprs = NIL; + bool self_join = (extra_clauses != NULL); /* Certainly can't prove uniqueness when there are no joinclauses */ if (restrictlist == NIL) @@ -1278,16 +1281,23 @@ innerrel_is_unique_ext(PlannerInfo *root, /* * Query the cache to see if we've managed to prove that innerrel is - * unique for any subset of this outerrel. We don't need an exact match, - * as extra outerrels can't make the innerrel any less unique (or more - * formally, the restrictlist for a join to a superset outerrel must be a - * superset of the conditions we successfully used before). + * unique for any subset of this outerrel. For non self-join search, we + * don't need an exact match, as extra outerrels can't make the innerrel + * any less unique (or more formally, the restrictlist for a join to a + * superset outerrel must be a superset of the conditions we successfully + * used before). For self-join search, we require an exact match of + * outerrels, because we need extra clauses to be valid for our case. + * Also, for self-join checking we've filtered the clauses list. Thus, + * for a self-join search, we can match only the result cached for another + * self-join check. */ foreach(lc, innerrel->unique_for_rels) { uniqueRelInfo = (UniqueRelInfo *) lfirst(lc); - if (bms_is_subset(uniqueRelInfo->outerrelids, outerrelids)) + if ((!self_join && bms_is_subset(uniqueRelInfo->outerrelids, outerrelids)) || + (self_join && bms_equal(uniqueRelInfo->outerrelids, outerrelids) && + uniqueRelInfo->self_join)) { if (extra_clauses) *extra_clauses = uniqueRelInfo->extra_clauses; @@ -1309,7 +1319,8 @@ innerrel_is_unique_ext(PlannerInfo *root, /* No cached information, so try to make the proof. */ if (is_innerrel_unique_for(root, joinrelids, outerrelids, innerrel, - jointype, restrictlist, &outer_exprs)) + jointype, restrictlist, + self_join ? &outer_exprs : NULL)) { /* * Cache the positive result for future probes, being sure to keep it @@ -1323,8 +1334,9 @@ innerrel_is_unique_ext(PlannerInfo *root, */ old_context = MemoryContextSwitchTo(root->planner_cxt); uniqueRelInfo = makeNode(UniqueRelInfo); - uniqueRelInfo->extra_clauses = outer_exprs; uniqueRelInfo->outerrelids = bms_copy(outerrelids); + uniqueRelInfo->self_join = self_join; + uniqueRelInfo->extra_clauses = outer_exprs; innerrel->unique_for_rels = lappend(innerrel->unique_for_rels, uniqueRelInfo); MemoryContextSwitchTo(old_context); |