diff options
Diffstat (limited to 'src/backend/optimizer/util/pathnode.c')
| -rw-r--r-- | src/backend/optimizer/util/pathnode.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c index 1ea89ff54c9..36aee35d462 100644 --- a/src/backend/optimizer/util/pathnode.c +++ b/src/backend/optimizer/util/pathnode.c @@ -1203,12 +1203,13 @@ create_tidscan_path(PlannerInfo *root, RelOptInfo *rel, List *tidquals, * pathnode. * * Note that we must handle subpaths = NIL, representing a dummy access path. + * Also, there are callers that pass root = NULL. */ AppendPath * create_append_path(PlannerInfo *root, RelOptInfo *rel, List *subpaths, List *partial_subpaths, - Relids required_outer, + List *pathkeys, Relids required_outer, int parallel_workers, bool parallel_aware, List *partitioned_rels, double rows) { @@ -1242,6 +1243,7 @@ create_append_path(PlannerInfo *root, pathnode->path.parallel_aware = parallel_aware; pathnode->path.parallel_safe = rel->consider_parallel; pathnode->path.parallel_workers = parallel_workers; + pathnode->path.pathkeys = pathkeys; pathnode->partitioned_rels = list_copy(partitioned_rels); /* @@ -1255,6 +1257,13 @@ create_append_path(PlannerInfo *root, */ if (pathnode->path.parallel_aware) { + /* + * We mustn't fiddle with the order of subpaths when the Append has + * pathkeys. The order they're listed in is critical to keeping the + * pathkeys valid. + */ + Assert(pathkeys == NIL); + subpaths = list_qsort(subpaths, append_total_cost_compare); partial_subpaths = list_qsort(partial_subpaths, append_startup_cost_compare); @@ -1262,6 +1271,15 @@ create_append_path(PlannerInfo *root, pathnode->first_partial_path = list_length(subpaths); pathnode->subpaths = list_concat(subpaths, partial_subpaths); + /* + * Apply query-wide LIMIT if known and path is for sole base relation. + * (Handling this at this low level is a bit klugy.) + */ + if (root != NULL && bms_equal(rel->relids, root->all_baserels)) + pathnode->limit_tuples = root->limit_tuples; + else + pathnode->limit_tuples = -1.0; + foreach(l, pathnode->subpaths) { Path *subpath = (Path *) lfirst(l); @@ -1278,8 +1296,9 @@ create_append_path(PlannerInfo *root, /* * If there's exactly one child path, the Append is a no-op and will be * discarded later (in setrefs.c); therefore, we can inherit the child's - * size, cost, and pathkeys if any. Otherwise, it's unsorted, and we must - * do the normal costsize calculation. + * size and cost, as well as its pathkeys if any (overriding whatever the + * caller might've said). Otherwise, we must do the normal costsize + * calculation. */ if (list_length(pathnode->subpaths) == 1) { @@ -1291,10 +1310,7 @@ create_append_path(PlannerInfo *root, pathnode->path.pathkeys = child->pathkeys; } else - { - pathnode->path.pathkeys = NIL; /* unsorted if more than 1 subpath */ cost_append(pathnode); - } /* If the caller provided a row estimate, override the computed value. */ if (rows >= 0) @@ -3759,7 +3775,7 @@ reparameterize_path(PlannerInfo *root, Path *path, } return (Path *) create_append_path(root, rel, childpaths, partialpaths, - required_outer, + apath->path.pathkeys, required_outer, apath->path.parallel_workers, apath->path.parallel_aware, apath->partitioned_rels, |