diff options
Diffstat (limited to 'src/backend/optimizer/path/costsize.c')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 69 |
1 files changed, 57 insertions, 12 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index e1523d15df1..c6e66e46f4a 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -3532,7 +3532,8 @@ final_cost_nestloop(PlannerInfo *root, NestPath *path, * join quals here, except for obtaining the scan selectivity estimate which * is really essential (but fortunately, use of caching keeps the cost of * getting that down to something reasonable). - * We also assume that cost_sort is cheap enough to use here. + * We also assume that cost_sort/cost_incremental_sort is cheap enough to use + * here. * * 'workspace' is to be filled with startup_cost, total_cost, and perhaps * other data to be used by final_cost_mergejoin @@ -3569,7 +3570,8 @@ initial_cost_mergejoin(PlannerInfo *root, JoinCostWorkspace *workspace, outerendsel, innerstartsel, innerendsel; - Path sort_path; /* dummy for result of cost_sort */ + Path sort_path; /* dummy for result of + * cost_sort/cost_incremental_sort */ /* Protect some assumptions below that rowcounts aren't zero */ if (outer_path_rows <= 0) @@ -3682,16 +3684,54 @@ initial_cost_mergejoin(PlannerInfo *root, JoinCostWorkspace *workspace, if (outersortkeys) /* do we need to sort outer? */ { - cost_sort(&sort_path, - root, - outersortkeys, - outer_path->disabled_nodes, - outer_path->total_cost, - outer_path_rows, - outer_path->pathtarget->width, - 0.0, - work_mem, - -1.0); + bool use_incremental_sort = false; + int presorted_keys; + + /* + * We choose to use incremental sort if it is enabled and there are + * presorted keys; otherwise we use full sort. + */ + if (enable_incremental_sort) + { + bool is_sorted PG_USED_FOR_ASSERTS_ONLY; + + is_sorted = pathkeys_count_contained_in(outersortkeys, + outer_path->pathkeys, + &presorted_keys); + Assert(!is_sorted); + + if (presorted_keys > 0) + use_incremental_sort = true; + } + + if (!use_incremental_sort) + { + cost_sort(&sort_path, + root, + outersortkeys, + outer_path->disabled_nodes, + outer_path->total_cost, + outer_path_rows, + outer_path->pathtarget->width, + 0.0, + work_mem, + -1.0); + } + else + { + cost_incremental_sort(&sort_path, + root, + outersortkeys, + presorted_keys, + outer_path->disabled_nodes, + outer_path->startup_cost, + outer_path->total_cost, + outer_path_rows, + outer_path->pathtarget->width, + 0.0, + work_mem, + -1.0); + } disabled_nodes += sort_path.disabled_nodes; startup_cost += sort_path.startup_cost; startup_cost += (sort_path.total_cost - sort_path.startup_cost) @@ -3711,6 +3751,11 @@ initial_cost_mergejoin(PlannerInfo *root, JoinCostWorkspace *workspace, if (innersortkeys) /* do we need to sort inner? */ { + /* + * We do not consider incremental sort for inner path, because + * incremental sort does not support mark/restore. + */ + cost_sort(&sort_path, root, innersortkeys, |