diff options
Diffstat (limited to 'src/backend/optimizer/util/relnode.c')
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 37 |
1 files changed, 18 insertions, 19 deletions
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index b197f144117..a2be2ede85e 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -373,7 +373,8 @@ build_join_rel(PlannerInfo *root, joinrel->cheapest_total_path = NULL; joinrel->cheapest_unique_path = NULL; joinrel->cheapest_parameterized_paths = NIL; - joinrel->lateral_relids = min_join_parameterization(root, joinrel->relids); + joinrel->lateral_relids = min_join_parameterization(root, joinrel->relids, + outer_rel, inner_rel); joinrel->relid = 0; /* indicates not a baserel */ joinrel->rtekind = RTE_JOIN; joinrel->min_attr = 0; @@ -508,29 +509,27 @@ build_join_rel(PlannerInfo *root, * because join_is_legal() needs the value to check a prospective join. */ Relids -min_join_parameterization(PlannerInfo *root, Relids joinrelids) +min_join_parameterization(PlannerInfo *root, + Relids joinrelids, + RelOptInfo *outer_rel, + RelOptInfo *inner_rel) { Relids result; - ListCell *lc; - - /* Easy if there are no lateral references */ - if (root->lateral_info_list == NIL) - return NULL; /* - * Scan lateral_info_list to find all the lateral references occurring in - * or below this join. + * Basically we just need the union of the inputs' lateral_relids, less + * whatever is already in the join. + * + * It's not immediately obvious that this is a valid way to compute the + * result, because it might seem that we're ignoring possible lateral refs + * of PlaceHolderVars that are due to be computed at the join but not in + * either input. However, because create_lateral_join_info() already + * charged all such PHV refs to each member baserel of the join, they'll + * be accounted for already in the inputs' lateral_relids. Likewise, we + * do not need to worry about doing transitive closure here, because that + * was already accounted for in the original baserel lateral_relids. */ - result = NULL; - foreach(lc, root->lateral_info_list) - { - LateralJoinInfo *ljinfo = (LateralJoinInfo *) lfirst(lc); - - if (bms_is_subset(ljinfo->lateral_rhs, joinrelids)) - result = bms_add_members(result, ljinfo->lateral_lhs); - } - - /* Remove any rels that are already included in the join */ + result = bms_union(outer_rel->lateral_relids, inner_rel->lateral_relids); result = bms_del_members(result, joinrelids); /* Maintain invariant that result is exactly NULL if empty */ |