diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index f12e388d723..c31f7d5aa65 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -14,7 +14,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.100 2007/04/21 21:01:45 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.101 2007/05/04 01:13:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -47,6 +47,8 @@ * tlist is the target list the query should produce * (this is NOT necessarily root->parse->targetList!) * tuple_fraction is the fraction of tuples we expect will be retrieved + * limit_tuples is a hard limit on number of tuples to retrieve, + * or -1 if no limit * * Output parameters: * *cheapest_path receives the overall-cheapest path for the query @@ -74,9 +76,13 @@ * from the plan to be retrieved * tuple_fraction >= 1: tuple_fraction is the absolute number of tuples * expected to be retrieved (ie, a LIMIT specification) + * Note that a nonzero tuple_fraction could come from outer context; it is + * therefore not redundant with limit_tuples. We use limit_tuples to determine + * whether a bounded sort can be used at runtime. */ void -query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, +query_planner(PlannerInfo *root, List *tlist, + double tuple_fraction, double limit_tuples, Path **cheapest_path, Path **sorted_path, double *num_groups) { @@ -354,7 +360,8 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, /* Figure cost for sorting */ cost_sort(&sort_path, root, root->query_pathkeys, cheapestpath->total_cost, - final_rel->rows, final_rel->width); + final_rel->rows, final_rel->width, + limit_tuples); } if (compare_fractional_path_costs(sortedpath, &sort_path, |