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Commitbab163e

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Fix old oversight in join removal logic.
Commit9e7e29c introduced an Assert thatjoin 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 --- butactually, the loop in join_is_removable skips PlaceHolderVars that are notreferenced above the join due to be removed. So, if we don't want anyempty eval_at sets, the right thing to do is to delete any now-unreferencedPlaceHolderVars from the data structure entirely.Per fuzz testing by Andreas Seltenreich. Back-patch to 9.3 where theaforesaid Assert was added.
1 parent58e09b9 commitbab163e

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3 files changed

+45
-6
lines changed

3 files changed

+45
-6
lines changed

‎src/backend/optimizer/plan/analyzejoins.c‎

Lines changed: 14 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -464,16 +464,24 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids)
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}
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/*
467-
* Likewise remove references from PlaceHolderVar data structures.
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* Likewise remove references from PlaceHolderVar data structures,
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* removing any no-longer-needed placeholders entirely.
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*/
469-
foreach(l,root->placeholder_list)
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for (l=list_head(root->placeholder_list);l!=NULL;l=nextl)
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{
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PlaceHolderInfo*phinfo= (PlaceHolderInfo*)lfirst(l);
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473-
phinfo->ph_eval_at=bms_del_member(phinfo->ph_eval_at,relid);
474-
Assert(!bms_is_empty(phinfo->ph_eval_at));
475-
Assert(!bms_is_member(relid,phinfo->ph_lateral));
476-
phinfo->ph_needed=bms_del_member(phinfo->ph_needed,relid);
474+
nextl=lnext(l);
475+
if (bms_is_subset(phinfo->ph_needed,joinrelids))
476+
root->placeholder_list=list_delete_ptr(root->placeholder_list,
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phinfo);
478+
else
479+
{
480+
phinfo->ph_eval_at=bms_del_member(phinfo->ph_eval_at,relid);
481+
Assert(!bms_is_empty(phinfo->ph_eval_at));
482+
Assert(!bms_is_member(relid,phinfo->ph_lateral));
483+
phinfo->ph_needed=bms_del_member(phinfo->ph_needed,relid);
484+
}
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}
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/*

‎src/test/regress/expected/join.out‎

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3862,6 +3862,22 @@ SELECT * FROM
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1 | 4567890123456789 | -4567890123456789 | 4567890123456789
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(5 rows)
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rollback;
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-- another join removal bug: we must clean up correctly when removing a PHV
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begin;
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create temp table uniquetbl (f1 text unique);
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explain (costs off)
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select t1.* from
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uniquetbl as t1
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left join (select *, '***'::text as d1 from uniquetbl) t2
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on t1.f1 = t2.f1
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left join uniquetbl t3
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on t2.d1 = t3.f1;
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QUERY PLAN
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--------------------------
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Seq Scan on uniquetbl t1
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(1 row)
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rollback;
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-- bug #8444: we've historically allowed duplicate aliases within aliased JOINs
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select * from

‎src/test/regress/sql/join.sql‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1247,6 +1247,21 @@ SELECT * FROM
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rollback;
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-- another join removal bug: we must clean up correctly when removing a PHV
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begin;
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create temp table uniquetbl (f1text unique);
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explain (costs off)
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select t1.*from
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uniquetblas t1
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left join (select*,'***'::textas d1from uniquetbl) t2
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ont1.f1=t2.f1
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left join uniquetbl t3
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ont2.d1=t3.f1;
1262+
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rollback;
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-- bug #8444: we've historically allowed duplicate aliases within aliased JOINs
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select*from

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