diff options
Diffstat (limited to 'src/backend/optimizer/path/allpaths.c')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index bdc77662bff..e7c6fdf40ac 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.190 2009/11/22 14:54:31 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.191 2009/11/28 00:46:19 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -898,41 +898,47 @@ make_rel_from_joinlist(PlannerInfo *root, List *joinlist) RelOptInfo * standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels) { - List **joinitems; int lev; RelOptInfo *rel; /* + * This function cannot be invoked recursively within any one planning + * problem, so join_rel_level[] can't be in use already. + */ + Assert(root->join_rel_level == NULL); + + /* * We employ a simple "dynamic programming" algorithm: we first find all * ways to build joins of two jointree items, then all ways to build joins * of three items (from two-item joins and single items), then four-item * joins, and so on until we have considered all ways to join all the * items into one rel. * - * joinitems[j] is a list of all the j-item rels. Initially we set - * joinitems[1] to represent all the single-jointree-item relations. + * root->join_rel_level[j] is a list of all the j-item rels. Initially we + * set root->join_rel_level[1] to represent all the single-jointree-item + * relations. */ - joinitems = (List **) palloc0((levels_needed + 1) * sizeof(List *)); + root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *)); - joinitems[1] = initial_rels; + root->join_rel_level[1] = initial_rels; for (lev = 2; lev <= levels_needed; lev++) { - ListCell *x; + ListCell *lc; /* * Determine all possible pairs of relations to be joined at this * level, and build paths for making each one from every available * pair of lower-level relations. */ - joinitems[lev] = join_search_one_level(root, lev, joinitems); + join_search_one_level(root, lev); /* * Do cleanup work on each just-processed rel. */ - foreach(x, joinitems[lev]) + foreach(lc, root->join_rel_level[lev]) { - rel = (RelOptInfo *) lfirst(x); + rel = (RelOptInfo *) lfirst(lc); /* Find and save the cheapest paths for this rel */ set_cheapest(rel); @@ -946,11 +952,13 @@ standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels) /* * We should have a single rel at the final level. */ - if (joinitems[levels_needed] == NIL) + if (root->join_rel_level[levels_needed] == NIL) elog(ERROR, "failed to build any %d-way joins", levels_needed); - Assert(list_length(joinitems[levels_needed]) == 1); + Assert(list_length(root->join_rel_level[levels_needed]) == 1); + + rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]); - rel = (RelOptInfo *) linitial(joinitems[levels_needed]); + root->join_rel_level = NULL; return rel; } |