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author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-08-06 22:14:07 -0400 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-08-06 22:14:28 -0400 |
commit | de0227d8aef18c1013b26ab193e48a5122435154 (patch) | |
tree | ce12b505feeaa3eff8dfadf55b6d7492bd7cf87b | |
parent | e663f7561683c8ba7663a8c2115e5a00f84f17c2 (diff) | |
download | postgresql-de0227d8aef18c1013b26ab193e48a5122435154.tar.gz postgresql-de0227d8aef18c1013b26ab193e48a5122435154.zip |
Fix old oversight in join removal logic.
Commit 9e7e29c75ad441450f9b8287bd51c13521641e3b introduced an Assert that
join removal didn't reduce the eval_at set of any PlaceHolderVar to empty.
At first glance it looks like join_is_removable ensures that's true --- but
actually, the loop in join_is_removable skips PlaceHolderVars that are not
referenced above the join due to be removed. So, if we don't want any
empty eval_at sets, the right thing to do is to delete any now-unreferenced
PlaceHolderVars from the data structure entirely.
Per fuzz testing by Andreas Seltenreich. Back-patch to 9.3 where the
aforesaid Assert was added.
-rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 20 | ||||
-rw-r--r-- | src/test/regress/expected/join.out | 16 | ||||
-rw-r--r-- | src/test/regress/sql/join.sql | 15 |
3 files changed, 45 insertions, 6 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 470db878175..dfb2e378312 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -464,16 +464,24 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids) } /* - * Likewise remove references from PlaceHolderVar data structures. + * Likewise remove references from PlaceHolderVar data structures, + * removing any no-longer-needed placeholders entirely. */ - foreach(l, root->placeholder_list) + for (l = list_head(root->placeholder_list); l != NULL; l = nextl) { PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l); - phinfo->ph_eval_at = bms_del_member(phinfo->ph_eval_at, relid); - Assert(!bms_is_empty(phinfo->ph_eval_at)); - Assert(!bms_is_member(relid, phinfo->ph_lateral)); - phinfo->ph_needed = bms_del_member(phinfo->ph_needed, relid); + nextl = lnext(l); + if (bms_is_subset(phinfo->ph_needed, joinrelids)) + root->placeholder_list = list_delete_ptr(root->placeholder_list, + phinfo); + else + { + phinfo->ph_eval_at = bms_del_member(phinfo->ph_eval_at, relid); + Assert(!bms_is_empty(phinfo->ph_eval_at)); + Assert(!bms_is_member(relid, phinfo->ph_lateral)); + phinfo->ph_needed = bms_del_member(phinfo->ph_needed, relid); + } } /* diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out index 4ba3bc73fea..d08f7052c6b 100644 --- a/src/test/regress/expected/join.out +++ b/src/test/regress/expected/join.out @@ -3863,6 +3863,22 @@ SELECT * FROM (5 rows) rollback; +-- another join removal bug: we must clean up correctly when removing a PHV +begin; +create temp table uniquetbl (f1 text unique); +explain (costs off) +select t1.* from + uniquetbl as t1 + left join (select *, '***'::text as d1 from uniquetbl) t2 + on t1.f1 = t2.f1 + left join uniquetbl t3 + on t2.d1 = t3.f1; + QUERY PLAN +-------------------------- + Seq Scan on uniquetbl t1 +(1 row) + +rollback; -- bug #8444: we've historically allowed duplicate aliases within aliased JOINs select * from int8_tbl x join (int4_tbl x cross join int4_tbl y) j on q1 = f1; -- error diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql index a27ca3f8bb9..43ca7f16c24 100644 --- a/src/test/regress/sql/join.sql +++ b/src/test/regress/sql/join.sql @@ -1247,6 +1247,21 @@ SELECT * FROM rollback; +-- another join removal bug: we must clean up correctly when removing a PHV +begin; + +create temp table uniquetbl (f1 text unique); + +explain (costs off) +select t1.* from + uniquetbl as t1 + left join (select *, '***'::text as d1 from uniquetbl) t2 + on t1.f1 = t2.f1 + left join uniquetbl t3 + on t2.d1 = t3.f1; + +rollback; + -- bug #8444: we've historically allowed duplicate aliases within aliased JOINs select * from |