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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-01-23 02:23:30 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-01-23 02:23:30 +0000 |
| commit | dddc2afb6e7fa614ce98f26ccdb1da8ee88e68ae (patch) | |
| tree | 221bf3f41c2545d4b81cb167cfa33a760505a27d /src/backend | |
| parent | 3b01217d7dc1441bdab0d07f7b041a2851b57008 (diff) | |
| download | postgresql-dddc2afb6e7fa614ce98f26ccdb1da8ee88e68ae.tar.gz postgresql-dddc2afb6e7fa614ce98f26ccdb1da8ee88e68ae.zip | |
The result of a FULL or RIGHT join can't be assumed to be sorted by the
left input's sorting, because null rows may be inserted at various points.
Per report from Ferenc Lutischá¸n.
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 7 | ||||
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 11 |
2 files changed, 14 insertions, 4 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 956dd991cd6..b1a25505b5e 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.82.2.1 2004/04/06 18:46:25 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.82.2.2 2005/01/23 02:23:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -271,7 +271,8 @@ sort_inner_and_outer(Query *root, cur_mergeclauses, innerrel); /* Build pathkeys representing output sort order. */ - merge_pathkeys = build_join_pathkeys(root, joinrel, outerkeys); + merge_pathkeys = build_join_pathkeys(root, joinrel, jointype, + outerkeys); /* * And now we can make the path. @@ -431,7 +432,7 @@ match_unsorted_outer(Query *root, * as a nestloop, and even if some of the mergeclauses are * implemented by qpquals rather than as true mergeclauses): */ - merge_pathkeys = build_join_pathkeys(root, joinrel, + merge_pathkeys = build_join_pathkeys(root, joinrel, jointype, outerpath->pathkeys); if (nestjoinOK) diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index fd3f3ab1869..16a9a1c130c 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 - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.53.4.1 2003/12/03 17:45:36 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.53.4.2 2005/01/23 02:23:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -861,7 +861,12 @@ 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. @@ -869,8 +874,12 @@ 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 |