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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 15:19:17 -04:00
parent 306d6e59f7
commit 64ad85860c
7 changed files with 52 additions and 32 deletions
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12
src/backend/optimizer/util/restrictinfo.c
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@ -410,7 +410,7 @@ extract_actual_clauses(List *restrictinfo_list,
* extract_actual_join_clauses
*
* Extract bare clauses from 'restrictinfo_list', separating those that
* syntactically match the join level from those that were pushed down.
* semantically match the join level from those that were pushed down.
* Pseudoconstant clauses are excluded from the results.
*
* This is only used at outer joins, since for plain joins we don't care
@ -433,15 +433,7 @@ extract_actual_join_clauses(List *restrictinfo_list,
Assert(IsA(rinfo, RestrictInfo));
/*
* We must check both is_pushed_down and required_relids, since an
* outer-join clause that's been pushed down to some lower join level
* via path parameterization will not be marked is_pushed_down;
* nonetheless, it must be treated as a filter clause not a join
* clause so far as the lower join level is concerned.
*/
if (rinfo->is_pushed_down ||
!bms_is_subset(rinfo->required_relids, joinrelids))
if (RINFO_IS_PUSHED_DOWN(rinfo, joinrelids))
{
if (!rinfo->pseudoconstant)
*otherquals = lappend(*otherquals, rinfo->clause);