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Change more places to be less trusting of RestrictInfo.is_pushed_down.

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On further reflection, commit e5d83995e didn't go far enough: pretty much
everywhere in the planner that examines a clause's is_pushed_down flag
ought to be changed to use the more complicated behavior where we also
check the clause's required_relids.  Otherwise we could make incorrect
decisions about whether, say, a clause is safe to use as a hash clause.

Some (many?) of these places are safe as-is, either because they are
never reached while considering a parameterized path, or because there
are additional checks that would reject a pushed-down clause anyway.
However, it seems smarter to just code them all the same way rather
than rely on easily-broken reasoning of that sort.

In support of that, invent a new macro RINFO_IS_PUSHED_DOWN that should
be used in place of direct tests on the is_pushed_down flag.

Like the previous patch, back-patch to all supported branches.

Discussion: https://postgr.es/m/f8128b11-c5bf-3539-48cd-234178b2314d@proxel.se
This commit is contained in:
Tom Lane
2018-04-20 15:19:16 -04:00
parent 68c23cba34
commit c792c7db41
10 changed files with 64 additions and 37 deletions
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10
src/backend/optimizer/plan/analyzejoins.c
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@@ -253,8 +253,7 @@ join_is_removable(PlannerInfo *root, SpecialJoinInfo *sjinfo)
* above the outer join, even if it references no other rels (it might
* be from WHERE, for example).
*/
if (restrictinfo->is_pushed_down ||
!bms_equal(restrictinfo->required_relids, joinrelids))
if (RINFO_IS_PUSHED_DOWN(restrictinfo, joinrelids))
{
/*
* If such a clause actually references the inner rel then join
@@ -422,8 +421,7 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids)
remove_join_clause_from_rels(root, rinfo, rinfo->required_relids);
if (rinfo->is_pushed_down ||
!bms_equal(rinfo->required_relids, joinrelids))
if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
{
/* Recheck that qual doesn't actually reference the target rel */
Assert(!bms_is_member(relid, rinfo->clause_relids));
@@ -1080,6 +1078,7 @@ is_innerrel_unique_for(PlannerInfo *root,
JoinType jointype,
List *restrictlist)
{
Relids joinrelids = bms_union(outerrelids, innerrel->relids);
List *clause_list = NIL;
ListCell *lc;
@@ -1098,7 +1097,8 @@ is_innerrel_unique_for(PlannerInfo *root,
* As noted above, if it's a pushed-down clause and we're at an outer
* join, we can't use it.
*/
if (restrictinfo->is_pushed_down && IS_OUTER_JOIN(jointype))
if (IS_OUTER_JOIN(jointype) &&
RINFO_IS_PUSHED_DOWN(restrictinfo, joinrelids))
continue;
/* Ignore if it's not a mergejoinable clause */