diff options
Diffstat (limited to 'src/backend/optimizer/path/pathkeys.c')
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index f93a027cd53..4f4b6720e1e 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 1.31 2001/03/22 03:59:35 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.32 2001/03/22 06:16:14 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -860,13 +860,13 @@ make_pathkeys_for_mergeclauses(Query *root, /* * When we are given multiple merge clauses, it's possible that - * some clauses refer to the same vars as earlier clauses. - * There's no reason for us to specify sort keys like (A,B,A) when - * (A,B) will do --- and adding redundant sort keys makes add_path - * think that this sort order is different from ones that are - * really the same, so don't do it. Since we now have a - * canonicalized pathkey, a simple ptrMember test is sufficient to - * detect redundant keys. + * some clauses refer to the same vars as earlier clauses. There's + * no reason for us to specify sort keys like (A,B,A) when (A,B) + * will do --- and adding redundant sort keys makes add_path think + * that this sort order is different from ones that are really the + * same, so don't do it. Since we now have a canonicalized + * pathkey, a simple ptrMember test is sufficient to detect + * redundant keys. */ if (!ptrMember(pathkey, pathkeys)) pathkeys = lappend(pathkeys, pathkey); |