diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index 4d8d31045dc..de3944b6b07 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 1.98 2007/01/05 22:19:32 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.99 2007/01/20 20:45:39 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -110,14 +110,14 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, * for "simple" rels. * * NOTE: in_info_list and append_rel_list were set up by subquery_planner, - * do not touch here + * do not touch here; eq_classes may contain data already, too. */ root->simple_rel_array_size = list_length(parse->rtable) + 1; root->simple_rel_array = (RelOptInfo **) palloc0(root->simple_rel_array_size * sizeof(RelOptInfo *)); root->join_rel_list = NIL; root->join_rel_hash = NULL; - root->equi_key_list = NIL; + root->canon_pathkeys = NIL; root->left_join_clauses = NIL; root->right_join_clauses = NIL; root->full_join_clauses = NIL; @@ -165,8 +165,8 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, * Examine the targetlist and qualifications, adding entries to baserel * targetlists for all referenced Vars. Restrict and join clauses are * added to appropriate lists belonging to the mentioned relations. We - * also build lists of equijoined keys for pathkey construction, and form - * a target joinlist for make_one_rel() to work from. + * also build EquivalenceClasses for provably equivalent expressions, + * and form a target joinlist for make_one_rel() to work from. * * Note: all subplan nodes will have "flat" (var-only) tlists. This * implies that all expression evaluations are done at the root of the @@ -179,16 +179,23 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, joinlist = deconstruct_jointree(root); /* - * Use the completed lists of equijoined keys to deduce any implied but - * unstated equalities (for example, A=B and B=C imply A=C). + * Reconsider any postponed outer-join quals now that we have built up + * equivalence classes. (This could result in further additions or + * mergings of classes.) */ - generate_implied_equalities(root); + reconsider_outer_join_clauses(root); /* - * We should now have all the pathkey equivalence sets built, so it's now - * possible to convert the requested query_pathkeys to canonical form. - * Also canonicalize the groupClause and sortClause pathkeys for use - * later. + * If we formed any equivalence classes, generate additional restriction + * clauses as appropriate. (Implied join clauses are formed on-the-fly + * later.) + */ + generate_base_implied_equalities(root); + + /* + * We have completed merging equivalence sets, so it's now possible to + * convert the requested query_pathkeys to canonical form. Also + * canonicalize the groupClause and sortClause pathkeys for use later. */ root->query_pathkeys = canonicalize_pathkeys(root, root->query_pathkeys); root->group_pathkeys = canonicalize_pathkeys(root, root->group_pathkeys); |