diff options
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 13 | ||||
| -rw-r--r-- | src/backend/optimizer/path/equivclass.c | 9 |
2 files changed, 18 insertions, 4 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index fa2cf61329c..e7a3e92bc20 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -2742,6 +2742,9 @@ generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows) * This allows us to do incremental sort on top of an index scan under a gather * merge node, i.e. parallelized. * + * If the require_parallel_safe is true, we also require the expressions to + * be parallel safe (which allows pushing the sort below Gather Merge). + * * XXX At the moment this can only ever return a list with a single element, * because it looks at query_pathkeys only. So we might return the pathkeys * directly, but it seems plausible we'll want to consider other orderings @@ -2749,7 +2752,8 @@ generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows) * merge joins. */ static List * -get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel) +get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel, + bool require_parallel_safe) { List *useful_pathkeys_list = NIL; @@ -2779,8 +2783,11 @@ get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel) * meet criteria of EC membership in the current relation, we * enable not just an incremental sort on the entirety of * query_pathkeys but also incremental sort below a JOIN. + * + * If requested, ensure the expression is parallel safe too. */ - if (!find_em_expr_usable_for_sorting_rel(pathkey_ec, rel)) + if (!find_em_expr_usable_for_sorting_rel(root, pathkey_ec, rel, + require_parallel_safe)) break; npathkeys++; @@ -2834,7 +2841,7 @@ generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_r generate_gather_paths(root, rel, override_rows); /* consider incremental sort for interesting orderings */ - useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel); + useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel, true); /* used for explicit (full) sort paths */ cheapest_partial_path = linitial(rel->partial_pathlist); diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c index 130f482eb62..a0a4699c813 100644 --- a/src/backend/optimizer/path/equivclass.c +++ b/src/backend/optimizer/path/equivclass.c @@ -800,7 +800,8 @@ find_em_expr_for_rel(EquivalenceClass *ec, RelOptInfo *rel) * applied in prepare_sort_from_pathkeys. */ Expr * -find_em_expr_usable_for_sorting_rel(EquivalenceClass *ec, RelOptInfo *rel) +find_em_expr_usable_for_sorting_rel(PlannerInfo *root, EquivalenceClass *ec, + RelOptInfo *rel, bool require_parallel_safe) { ListCell *lc_em; @@ -831,6 +832,12 @@ find_em_expr_usable_for_sorting_rel(EquivalenceClass *ec, RelOptInfo *rel) continue; /* + * If requested, reject expressions that are not parallel-safe. + */ + if (require_parallel_safe && !is_parallel_safe(root, (Node *) em_expr)) + continue; + + /* * As long as the expression isn't volatile then * prepare_sort_from_pathkeys is able to generate a new target entry, * so there's no need to verify that one already exists. |