diff options
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 71 |
1 files changed, 3 insertions, 68 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 8e73bd2f419..ac5d4a72d45 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.71 2002/09/04 20:31:20 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.72 2002/11/24 21:52:14 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -42,8 +42,6 @@ static void match_unsorted_inner(Query *root, RelOptInfo *joinrel, static void hash_inner_and_outer(Query *root, RelOptInfo *joinrel, RelOptInfo *outerrel, RelOptInfo *innerrel, List *restrictlist, JoinType jointype); -static Path *best_innerjoin(List *join_paths, List *outer_relid, - JoinType jointype); static List *select_mergejoin_clauses(RelOptInfo *joinrel, RelOptInfo *outerrel, RelOptInfo *innerrel, @@ -351,8 +349,8 @@ match_unsorted_outer(Query *root, * Get the best innerjoin indexpath (if any) for this outer rel. It's * the same for all outer paths. */ - bestinnerjoin = best_innerjoin(innerrel->innerjoin, outerrel->relids, - jointype); + bestinnerjoin = best_inner_indexscan(root, innerrel, + outerrel->relids, jointype); foreach(i, outerrel->pathlist) { @@ -813,69 +811,6 @@ hash_inner_and_outer(Query *root, } /* - * best_innerjoin - * Find the cheapest index path that has already been identified by - * indexable_joinclauses() as being a possible inner path for the given - * outer relation(s) in a nestloop join. - * - * We compare indexpaths on total_cost only, assuming that they will all have - * zero or negligible startup_cost. We might have to think harder someday... - * - * 'join_paths' is a list of potential inner indexscan join paths - * 'outer_relids' is the relid list of the outer join relation - * - * Returns the pathnode of the best path, or NULL if there's no - * usable path. - */ -static Path * -best_innerjoin(List *join_paths, Relids outer_relids, JoinType jointype) -{ - Path *cheapest = (Path *) NULL; - bool isouterjoin; - List *join_path; - - /* - * Nestloop only supports inner and left joins. - */ - switch (jointype) - { - case JOIN_INNER: - isouterjoin = false; - break; - case JOIN_LEFT: - isouterjoin = true; - break; - default: - return NULL; - } - - foreach(join_path, join_paths) - { - IndexPath *path = (IndexPath *) lfirst(join_path); - - Assert(IsA(path, IndexPath)); - - /* - * If processing an outer join, only use explicit join clauses in - * the inner indexscan. For inner joins we need not be so picky. - */ - if (isouterjoin && !path->alljoinquals) - continue; - - /* - * path->joinrelids is the set of base rels that must be part of - * outer_relids in order to use this inner path, because those - * rels are used in the index join quals of this inner path. - */ - if (is_subseti(path->joinrelids, outer_relids) && - (cheapest == NULL || - compare_path_costs((Path *) path, cheapest, TOTAL_COST) < 0)) - cheapest = (Path *) path; - } - return cheapest; -} - -/* * select_mergejoin_clauses * Select mergejoin clauses that are usable for a particular join. * Returns a list of RestrictInfo nodes for those clauses. |