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Fix Asserts in calc_non_nestloop_required_outer().

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These were not testing the same thing as the comparable Assert
in calc_nestloop_required_outer(), because we neglected to map
the given Paths' relids to top-level relids.  When considering
a partition child join the latter is the correct thing to do.

This oversight is old, but since it's only an overly-weak Assert
check there doesn't seem to be much value in back-patching.

Richard Guo (with cosmetic changes and comment updates by me)

Discussion: https://postgr.es/m/CAMbWs49sqbe9GBZ8sy8dSfKRNURgicR85HX8vgzcgQsPF0XY1w@mail.gmail.com
This commit is contained in:
Tom Lane 2024-01-10 13:51:36 -05:00
parent d641b827af
commit add673b897
2 changed files with 29 additions and 4 deletions
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7
src/backend/optimizer/path/joinpath.c
View File

@ -730,8 +730,11 @@ try_nestloop_path(PlannerInfo *root,
return;
/*
* Paths are parameterized by top-level parents, so run parameterization
* tests on the parent relids.
* Any parameterization of the input paths refers to topmost parents of
* the relevant relations, because reparameterize_path_by_child() hasn't
* been called yet. So we must consider topmost parents of the relations
* being joined, too, while determining parameterization of the result and
* checking for disallowed parameterization cases.
*/
if (innerrel->top_parent_relids)
innerrelids = innerrel->top_parent_relids;

26
src/backend/optimizer/util/pathnode.c
View File

@ -2360,6 +2360,9 @@ create_foreign_upper_path(PlannerInfo *root, RelOptInfo *rel,
* calc_nestloop_required_outer
* Compute the required_outer set for a nestloop join path
*
* Note: when considering a child join, the inputs nonetheless use top-level
* parent relids
*
* Note: result must not share storage with either input
*/
Relids
@ -2394,11 +2397,30 @@ calc_non_nestloop_required_outer(Path *outer_path, Path *inner_path)
{
Relids outer_paramrels = PATH_REQ_OUTER(outer_path);
Relids inner_paramrels = PATH_REQ_OUTER(inner_path);
Relids innerrelids PG_USED_FOR_ASSERTS_ONLY;
Relids outerrelids PG_USED_FOR_ASSERTS_ONLY;
Relids required_outer;
/*
* Any parameterization of the input paths refers to topmost parents of
* the relevant relations, because reparameterize_path_by_child() hasn't
* been called yet. So we must consider topmost parents of the relations
* being joined, too, while checking for disallowed parameterization
* cases.
*/
if (inner_path->parent->top_parent_relids)
innerrelids = inner_path->parent->top_parent_relids;
else
innerrelids = inner_path->parent->relids;
if (outer_path->parent->top_parent_relids)
outerrelids = outer_path->parent->top_parent_relids;
else
outerrelids = outer_path->parent->relids;
/* neither path can require rels from the other */
Assert(!bms_overlap(outer_paramrels, inner_path->parent->relids));
Assert(!bms_overlap(inner_paramrels, outer_path->parent->relids));
Assert(!bms_overlap(outer_paramrels, innerrelids));
Assert(!bms_overlap(inner_paramrels, outerrelids));
/* form the union ... */
required_outer = bms_union(outer_paramrels, inner_paramrels);
/* we do not need an explicit test for empty; bms_union gets it right */