Backport into build-200909221805-5.1.37sp1

> ------------------------------------------------------------
> revno: 3068
> revision-id: ramil@mysql.com-20090813194928-3djdqvpock0pxhgp
> parent: li-bing.song@sun.com-20090813024857-1emgf5lhj0zikoj8
> committer: Ramil Kalimullin <ramil@mysql.com>
> branch nick: mysql-5.1-bugteam
> timestamp: Fri 2009-08-14 00:49:28 +0500
> message:
>   Fix for bug #46614: Assertion in show_create_trigger() 
>   on SHOW CREATE TRIGGER + MERGE table
>   
>   Problem: SHOW CREATE TRIGGER erroneously relies on fact
>   that we have the only underlying table for a trigger
>   (wrong for merge tables).
>   
>   Fix: remove erroneous assert().

mysql-test/r/merge.result

@@ -2141,4 +2141,16 @@ SELECT * FROM m1;
 c1
 DROP TABLE m1;
 DROP TABLE t1;
+#
+# Bug #46614: Assertion in show_create_trigger()
+#
+CREATE TABLE t1(a int);
+CREATE TABLE t2(a int);
+CREATE TABLE t3(a int) ENGINE = MERGE UNION(t1, t2);
+CREATE TRIGGER tr1 AFTER INSERT ON t3 FOR EACH ROW CALL foo();
+SHOW CREATE TRIGGER tr1;
+Trigger	sql_mode	SQL Original Statement	character_set_client	collation_connection	Database Collation
+tr1		CREATE DEFINER=`root`@`localhost` TRIGGER tr1 AFTER INSERT ON t3 FOR EACH ROW CALL foo()	latin1	latin1_swedish_ci	latin1_swedish_ci
+DROP TRIGGER tr1;
+DROP TABLE t1, t2, t3;
 End of 5.1 tests

mysql-test/t/merge.test

@@ -1555,4 +1555,15 @@ SELECT * FROM m1;
 DROP TABLE m1;
 DROP TABLE t1;
 
+--echo #
+--echo # Bug #46614: Assertion in show_create_trigger()
+--echo #
+CREATE TABLE t1(a int);
+CREATE TABLE t2(a int);
+CREATE TABLE t3(a int) ENGINE = MERGE UNION(t1, t2);
+CREATE TRIGGER tr1 AFTER INSERT ON t3 FOR EACH ROW CALL foo();
+SHOW CREATE TRIGGER tr1;
+DROP TRIGGER tr1;
+DROP TABLE t1, t2, t3;
+
 --echo End of 5.1 tests

sql/sql_show.cc

@@ -7098,8 +7098,6 @@ bool show_create_trigger(THD *thd, const sp_name *trg_name)
     /* Perform closing actions and return error status. */
   }
 
-  DBUG_ASSERT(num_tables == 1);
-
   Table_triggers_list *triggers= lst->table->triggers;
 
   if (!triggers)