diff options
Diffstat (limited to 'src/backend/optimizer/path/pathkeys.c')
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index e10a41b9518..d2c6de54dd7 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -11,7 +11,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.63 2004/12/31 22:00:04 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.64 2005/01/23 02:21:26 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -858,7 +858,12 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery) * vars they were joined with; furthermore, it doesn't matter what kind * of join algorithm is actually used. * + * EXCEPTION: in a FULL or RIGHT join, we cannot treat the result as + * having the outer path's path keys, because null lefthand rows may be + * inserted at random points. It must be treated as unsorted. + * * 'joinrel' is the join relation that paths are being formed for + * 'jointype' is the join type (inner, left, full, etc) * 'outer_pathkeys' is the list of the current outer path's path keys * * Returns the list of new path keys. @@ -866,8 +871,12 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery) List * build_join_pathkeys(Query *root, RelOptInfo *joinrel, + JoinType jointype, List *outer_pathkeys) { + if (jointype == JOIN_FULL || jointype == JOIN_RIGHT) + return NIL; + /* * This used to be quite a complex bit of code, but now that all * pathkey sublists start out life canonicalized, we don't have to do |