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authorTom Lane <tgl@sss.pgh.pa.us>2005-01-23 02:22:34 +0000
committerTom Lane <tgl@sss.pgh.pa.us>2005-01-23 02:22:34 +0000
commit5b7a866b98c30f4463a68671a6ef4d64c03b3559 (patch)
tree20bab9b7518c59b99cb4224eb84bd2e5d545b3ae /src
parent3a4589056d8d5c2a14e426770776107312988ef4 (diff)
downloadpostgresql-5b7a866b98c30f4463a68671a6ef4d64c03b3559.tar.gz
postgresql-5b7a866b98c30f4463a68671a6ef4d64c03b3559.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')
-rw-r--r--src/backend/optimizer/path/joinpath.c7
-rw-r--r--src/backend/optimizer/path/pathkeys.c11
-rw-r--r--src/include/optimizer/paths.h3
3 files changed, 16 insertions, 5 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index 65c7690af47..0a2619d8f5e 100644
--- a/src/backend/optimizer/path/joinpath.c
+++ b/src/backend/optimizer/path/joinpath.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.91 2004/12/31 22:00:04 pgsql Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.91.4.1 2005/01/23 02:22:27 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 e10a41b9518..1ac2787f2b8 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 1.63.4.1 2005/01/23 02:22:27 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
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 97644f3cfcd..1d4c78b8109 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/optimizer/paths.h,v 1.77 2004/12/31 22:03:36 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/paths.h,v 1.77.4.1 2005/01/23 02:22:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -114,6 +114,7 @@ extern List *build_subquery_pathkeys(Query *root, RelOptInfo *rel,
Query *subquery);
extern List *build_join_pathkeys(Query *root,
RelOptInfo *joinrel,
+ JoinType jointype,
List *outer_pathkeys);
extern List *make_pathkeys_for_sortclauses(List *sortclauses,
List *tlist);