diff options
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 215d03a9719..d94d46f52da 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.97.2.1 2005/11/22 18:23:10 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.97.2.2 2007/05/22 01:40:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -295,10 +295,11 @@ sort_inner_and_outer(PlannerInfo *root, * only outer paths that are already ordered well enough for merging). * * We always generate a nestloop path for each available outer path. - * In fact we may generate as many as four: one on the cheapest-total-cost + * In fact we may generate as many as five: one on the cheapest-total-cost * inner path, one on the same with materialization, one on the - * cheapest-startup-cost inner path (if different), - * and one on the best inner-indexscan path (if any). + * cheapest-startup-cost inner path (if different), one on the + * cheapest-total inner-indexscan path (if any), and one on the + * cheapest-startup inner-indexscan path (if different). * * We also consider mergejoins if mergejoin clauses are available. We have * two ways to generate the inner path for a mergejoin: sort the cheapest @@ -334,7 +335,8 @@ match_unsorted_outer(PlannerInfo *root, Path *inner_cheapest_startup = innerrel->cheapest_startup_path; Path *inner_cheapest_total = innerrel->cheapest_total_path; Path *matpath = NULL; - Path *bestinnerjoin = NULL; + Path *index_cheapest_startup = NULL; + Path *index_cheapest_total = NULL; ListCell *l; /* @@ -392,11 +394,12 @@ match_unsorted_outer(PlannerInfo *root, create_material_path(innerrel, inner_cheapest_total); /* - * Get the best innerjoin indexpath (if any) for this outer rel. It's - * the same for all outer paths. + * Get the best innerjoin indexpaths (if any) for this outer rel. + * They're the same for all outer paths. */ - bestinnerjoin = best_inner_indexscan(root, innerrel, - outerrel->relids, jointype); + best_inner_indexscan(root, innerrel, outerrel->relids, jointype, + &index_cheapest_startup, + &index_cheapest_total); } foreach(l, outerrel->pathlist) @@ -437,8 +440,8 @@ match_unsorted_outer(PlannerInfo *root, * Always consider a nestloop join with this outer and * cheapest-total-cost inner. When appropriate, also consider * using the materialized form of the cheapest inner, the - * cheapest-startup-cost inner path, and the best innerjoin - * indexpath. + * cheapest-startup-cost inner path, and the cheapest innerjoin + * indexpaths. */ add_path(joinrel, (Path *) create_nestloop_path(root, @@ -466,13 +469,23 @@ match_unsorted_outer(PlannerInfo *root, inner_cheapest_startup, restrictlist, merge_pathkeys)); - if (bestinnerjoin != NULL) + if (index_cheapest_total != NULL) add_path(joinrel, (Path *) create_nestloop_path(root, joinrel, jointype, outerpath, - bestinnerjoin, + index_cheapest_total, + restrictlist, + merge_pathkeys)); + if (index_cheapest_startup != NULL && + index_cheapest_startup != index_cheapest_total) + add_path(joinrel, (Path *) + create_nestloop_path(root, + joinrel, + jointype, + outerpath, + index_cheapest_startup, restrictlist, merge_pathkeys)); } |