From: Tom Lane Date: Fri, 11 Jan 2008 04:02:26 +0000 (+0000) Subject: Fix a conceptual error in my patch of 2007-10-26 that avoided considering X-Git-Tag: REL8_2_7~37 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bcabf2195b8903c95cca187e44bd073de0e2f288;p=thirdparty%2Fpostgresql.git Fix a conceptual error in my patch of 2007-10-26 that avoided considering clauseless joins of relations that have unexploited join clauses. Rather than looking at every other base relation in the query, the correct thing is to examine the other relations in the "initial_rels" list of the current make_rel_from_joinlist() invocation, because those are what we actually have the ability to join against. This might be a subset of the whole query in cases where join_collapse_limit or from_collapse_limit or full joins have prevented merging the whole query into a single join problem. This is a bit untidy because we have to pass those rels down through a new PlannerInfo field, but it's necessary. Per bug #3865 from Oleg Kharin. --- diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index 1e195398f3f..bd8c7816c40 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 1.154.2.1 2007/01/28 18:50:48 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.154.2.2 2008/01/11 04:02:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -628,7 +628,12 @@ make_rel_from_joinlist(PlannerInfo *root, List *joinlist) /* * Consider the different orders in which we could join the rels, * using either GEQO or regular optimizer. + * + * We put the initial_rels list into a PlannerInfo field because + * has_legal_joinclause() needs to look at it (ugly :-(). */ + root->initial_rels = initial_rels; + if (enable_geqo && levels_needed >= geqo_threshold) return geqo(root, levels_needed, initial_rels); else diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c index fcb36c9b22e..12d7a2295c7 100644 --- a/src/backend/optimizer/path/joinrels.c +++ b/src/backend/optimizer/path/joinrels.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.81.2.4 2007/10/26 18:10:58 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.81.2.5 2008/01/11 04:02:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -837,33 +837,27 @@ has_join_restriction(PlannerInfo *root, RelOptInfo *rel) * Detect whether the specified relation can legally be joined * to any other rels using join clauses. * - * We consider only joins to single other relations. This is sufficient - * to get a "true" result in most real queries, and an occasional erroneous - * "false" will only cost a bit more planning time. The reason for this - * limitation is that considering joins to other joins would require proving - * that the other join rel can legally be formed, which seems like too much - * trouble for something that's only a heuristic to save planning time. + * We consider only joins to single other relations in the current + * initial_rels list. This is sufficient to get a "true" result in most real + * queries, and an occasional erroneous "false" will only cost a bit more + * planning time. The reason for this limitation is that considering joins to + * other joins would require proving that the other join rel can legally be + * formed, which seems like too much trouble for something that's only a + * heuristic to save planning time. (Note: we must look at initial_rels + * and not all of the query, since when we are planning a sub-joinlist we + * may be forced to make clauseless joins within initial_rels even though + * there are join clauses linking to other parts of the query.) */ static bool has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel) { - Index rti; + ListCell *lc; - for (rti = 1; rti < root->simple_rel_array_size; rti++) + foreach(lc, root->initial_rels) { - RelOptInfo *rel2 = root->simple_rel_array[rti]; + RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc); - /* there may be empty slots corresponding to non-baserel RTEs */ - if (rel2 == NULL) - continue; - - Assert(rel2->relid == rti); /* sanity check on array */ - - /* ignore RTEs that are "other rels" */ - if (rel2->reloptkind != RELOPT_BASEREL) - continue; - - /* ignore RTEs that are already in "rel" */ + /* ignore rels that are already in "rel" */ if (bms_overlap(rel->relids, rel2->relids)) continue; diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index 1dc9e97fdb6..de43c96a579 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 1.97.2.1 2007/10/04 20:44:55 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.97.2.2 2008/01/11 04:02:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -122,6 +122,7 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, root->right_join_clauses = NIL; root->full_join_clauses = NIL; root->oj_info_list = NIL; + root->initial_rels = NIL; /* * Construct RelOptInfo nodes for all base relations in query, and diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index 34727773e06..865c7caff66 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.128.2.4 2007/08/31 01:44:14 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.128.2.5 2008/01/11 04:02:26 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -118,6 +118,9 @@ typedef struct PlannerInfo bool hasHavingQual; /* true if havingQual was non-null */ bool hasPseudoConstantQuals; /* true if any RestrictInfo has * pseudoconstant = true */ + + /* At the end to avoid breaking existing 8.2 add-ons */ + List *initial_rels; /* RelOptInfos we are now trying to join */ } PlannerInfo;