diff options
| author | Tomas Vondra <tomas.vondra@postgresql.org> | 2020-04-07 16:43:18 +0200 |
|---|---|---|
| committer | Tomas Vondra <tomas.vondra@postgresql.org> | 2020-04-07 16:43:22 +0200 |
| commit | ba3e76cc571eba3dea19c9465ff15ac3ac186576 (patch) | |
| tree | 5f570294c455cec9fa956b99811453753bf872b1 /src/include/optimizer/paths.h | |
| parent | c7654f6a37792ab9525ff98b710c23b27c7868a5 (diff) | |
Consider Incremental Sort paths at additional places
Commit d2d8a229bc introduced Incremental Sort, but it was considered
only in create_ordered_paths() as an alternative to regular Sort. There
are many other places that require sorted input and might benefit from
considering Incremental Sort too.
This patch modifies a number of those places, but not all. The concern
is that just adding Incremental Sort to any place that already adds
Sort may increase the number of paths considered, negatively affecting
planning time, without any benefit. So we've taken a more conservative
approach, based on analysis of which places do affect a set of queries
that did seem practical. This means some less common queries may not
benefit from Incremental Sort yet.
Author: Tomas Vondra
Reviewed-by: James Coleman
Discussion: https://postgr.es/m/CAPpHfds1waRZ=NOmueYq0sx1ZSCnt+5QJvizT8ndT2=etZEeAQ@mail.gmail.com
Diffstat (limited to 'src/include/optimizer/paths.h')
| -rw-r--r-- | src/include/optimizer/paths.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h index ab61f306cb9..10b6e810796 100644 --- a/src/include/optimizer/paths.h +++ b/src/include/optimizer/paths.h @@ -54,6 +54,8 @@ extern RelOptInfo *standard_join_search(PlannerInfo *root, int levels_needed, extern void generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows); +extern void generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, + bool override_rows); extern int compute_parallel_worker(RelOptInfo *rel, double heap_pages, double index_pages, int max_workers); extern void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel, @@ -132,6 +134,7 @@ extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root, Index sortref, Relids rel, bool create_it); +extern Expr *find_em_expr_for_rel(EquivalenceClass *ec, RelOptInfo *rel); extern void generate_base_implied_equalities(PlannerInfo *root); extern List *generate_join_implied_equalities(PlannerInfo *root, Relids join_relids, |