From cc5e80b8d1c4bf86aa99b54c938e9048e10bf93a Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 2 Jul 2005 23:00:42 +0000 Subject: Teach planner about some cases where a restriction clause can be propagated inside an outer join. In particular, given LEFT JOIN ON (A = B) WHERE A = constant, we cannot conclude that B = constant at the top level (B might be null instead), but we can nonetheless put a restriction B = constant into the quals for B's relation, since no inner-side rows not meeting that condition can contribute to the final result. Similarly, given FULL JOIN USING (J) WHERE J = constant, we can't directly conclude that either input J variable = constant, but it's OK to push such quals into each input rel. Per recent gripe from Kim Bisgaard. Along the way, remove 'valid_everywhere' flag from RestrictInfo, as on closer analysis it was not being used for anything, and was defined backwards anyway. --- src/backend/optimizer/path/orindxpath.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'src/backend/optimizer/path/orindxpath.c') diff --git a/src/backend/optimizer/path/orindxpath.c b/src/backend/optimizer/path/orindxpath.c index 7eadd220b94..884329edd97 100644 --- a/src/backend/optimizer/path/orindxpath.c +++ b/src/backend/optimizer/path/orindxpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.72 2005/06/09 04:18:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.73 2005/07/02 23:00:40 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -90,16 +90,13 @@ create_or_index_quals(PlannerInfo *root, RelOptInfo *rel) ListCell *i; /* - * Find potentially interesting OR joinclauses. We must ignore any - * joinclauses that are not marked valid_everywhere, because they - * cannot be pushed down due to outer-join rules. + * Find potentially interesting OR joinclauses. */ foreach(i, rel->joininfo) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(i); - if (restriction_is_or_clause(rinfo) && - rinfo->valid_everywhere) + if (restriction_is_or_clause(rinfo)) { /* * Use the generate_bitmap_or_paths() machinery to estimate @@ -140,8 +137,7 @@ create_or_index_quals(PlannerInfo *root, RelOptInfo *rel) * Convert the path's indexclauses structure to a RestrictInfo tree, * and add it to the rel's restriction list. */ - newrinfos = make_restrictinfo_from_bitmapqual((Path *) bestpath, - true, true); + newrinfos = make_restrictinfo_from_bitmapqual((Path *) bestpath, true); Assert(list_length(newrinfos) == 1); or_rinfo = (RestrictInfo *) linitial(newrinfos); Assert(IsA(or_rinfo, RestrictInfo)); -- cgit v1.2.3