diff options
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index fe0e4d7c201..f54c3931ce4 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -148,6 +148,32 @@ add_paths_to_joinrel(PlannerInfo *root, } /* + * However, when a LATERAL subquery is involved, we have to be a bit + * laxer, because there may simply not be any paths for the joinrel that + * aren't parameterized by whatever the subquery is parameterized by. + * Hence, add to param_source_rels anything that is in the minimum + * parameterization of either input (and not in the other input). + * + * XXX need a more principled way of determining minimum parameterization. + */ + if (outerrel->cheapest_total_path == NULL) + { + Path *cheapest = (Path *) linitial(outerrel->cheapest_parameterized_paths); + + param_source_rels = bms_join(param_source_rels, + bms_difference(PATH_REQ_OUTER(cheapest), + innerrel->relids)); + } + if (innerrel->cheapest_total_path == NULL) + { + Path *cheapest = (Path *) linitial(innerrel->cheapest_parameterized_paths); + + param_source_rels = bms_join(param_source_rels, + bms_difference(PATH_REQ_OUTER(cheapest), + outerrel->relids)); + } + + /* * 1. Consider mergejoin paths where both relations must be explicitly * sorted. Skip this if we can't mergejoin. */ |