diff options
| author | Tom Lane | 2012-08-30 18:32:22 +0000 |
|---|---|---|
| committer | Tom Lane | 2012-08-30 18:33:00 +0000 |
| commit | 77387f0ac859c099c6ab669db1e7a852524696c4 (patch) | |
| tree | bd1de1f24e2b5b9f90e5c11eb18d11ba041eab77 /src/include/optimizer | |
| parent | 35738b5906bb80bc4bb77ce1adea7dfbd3f64274 (diff) | |
Suppress creation of backwardly-indexed paths for LATERAL join clauses.
Given a query such as
SELECT * FROM foo JOIN LATERAL (SELECT foo.var1) ss(x) ON ss.x = foo.var2
the existence of the join clause "ss.x = foo.var2" encourages indxpath.c to
build a parameterized path for foo using any index available for foo.var2.
This is completely useless activity, though, since foo has got to be on the
outside not the inside of any nestloop join with ss. It's reasonably
inexpensive to add tests that prevent creation of such paths, so let's do
that.
Diffstat (limited to 'src/include/optimizer')
| -rw-r--r-- | src/include/optimizer/paths.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h index b6fb8ee5ce9..165856de0bc 100644 --- a/src/include/optimizer/paths.h +++ b/src/include/optimizer/paths.h @@ -127,7 +127,8 @@ extern void mutate_eclass_expressions(PlannerInfo *root, void *context); extern List *generate_implied_equalities_for_indexcol(PlannerInfo *root, IndexOptInfo *index, - int indexcol); + int indexcol, + Relids prohibited_rels); extern bool have_relevant_eclass_joinclause(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2); extern bool has_relevant_eclass_joinclause(PlannerInfo *root, |