Previous fix for "x FULL JOIN y ON true" failed to handle the case

where there was also a WHERE-clause restriction that applied to the
join.  The check on restrictlist == NIL is really unnecessary anyway,
because select_mergejoin_clauses already checked for and complained
about any unmergejoinable join clauses.  So just take it out.

diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index b75cb6128d7e8204be7898df009ba1c01ad2dbab..7ee1542ecdf6edf294e6b1369aa1a6549091351a 100644 (file)
--- 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 1.93 2005/04/19 22:35:15 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.94 2005/05/24 18:02:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -499,15 +499,10 @@ match_unsorted_outer(Query *root,
         * nestloop path, but since mergejoin is our only join type that
         * supports FULL JOIN, it's necessary to generate a clauseless
         * mergejoin path instead.
-        *
-        * Unfortunately this can't easily be extended to handle the case
-        * where there are joinclauses but none of them use mergejoinable
-        * operators; nodeMergejoin.c can only do a full join correctly if
-        * all the joinclauses are mergeclauses.
         */
        if (mergeclauses == NIL)
        {
-           if (jointype == JOIN_FULL && restrictlist == NIL)
+           if (jointype == JOIN_FULL)
                 /* okay to try for mergejoin */ ;
            else
                continue;