Merge gkodinov@bk-internal.mysql.com:/home/bk/mysql-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B27786-5.0-opt

mysql-test/r/view.result

@@ -3319,4 +3319,39 @@ lgid	clid
 2	YES
 DROP VIEW v1;
 DROP table t1,t2;
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+CREATE VIEW v1 AS SELECT a FROM t1 ORDER BY a;
+SELECT * FROM t1 UNION SELECT * FROM v1;
+a
+1
+2
+3
+EXPLAIN SELECT * FROM t1 UNION SELECT * FROM v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+2	UNION	t1	ALL	NULL	NULL	NULL	NULL	3	
+NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT * FROM v1 UNION SELECT * FROM t1;
+a
+1
+2
+3
+EXPLAIN SELECT * FROM v1 UNION SELECT * FROM t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+2	UNION	t1	ALL	NULL	NULL	NULL	NULL	3	
+NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT * FROM t1 UNION SELECT * FROM v1 ORDER BY a;
+a
+1
+2
+3
+EXPLAIN SELECT * FROM t1 UNION SELECT * FROM v1 ORDER BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+2	UNION	t1	ALL	NULL	NULL	NULL	NULL	3	
+NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	Using filesort
+DROP VIEW v1;
+DROP TABLE t1;
 End of 5.0 tests.

mysql-test/t/view.test

@@ -3205,4 +3205,20 @@ SELECT * FROM v1;
 DROP VIEW v1;
 DROP table t1,t2;
 
+#
+# Bug#27786: Inconsistent Operation Performing UNION On View With ORDER BY 
+#
+CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2),(3);
+CREATE VIEW v1 AS SELECT a FROM t1 ORDER BY a;
+
+SELECT * FROM t1 UNION SELECT * FROM v1;
+EXPLAIN SELECT * FROM t1 UNION SELECT * FROM v1;
+SELECT * FROM v1 UNION SELECT * FROM t1;
+EXPLAIN SELECT * FROM v1 UNION SELECT * FROM t1;
+SELECT * FROM t1 UNION SELECT * FROM v1 ORDER BY a;
+EXPLAIN SELECT * FROM t1 UNION SELECT * FROM v1 ORDER BY a;
+
+DROP VIEW v1;
+DROP TABLE t1;
+
 --echo End of 5.0 tests.

sql/sql_lex.h

@@ -468,6 +468,7 @@ public:
   bool change_result(select_subselect *result, select_subselect *old_result);
   void set_limit(st_select_lex *values);
   void set_thd(THD *thd_arg) { thd= thd_arg; }
+  inline bool is_union (); 
 
   friend void lex_start(THD *thd, uchar *buf, uint length);
   friend int subselect_union_engine::exec();
@@ -700,6 +701,13 @@ public:
 };
 typedef class st_select_lex SELECT_LEX;
 
+
+inline bool st_select_lex_unit::is_union ()
+{ 
+  return first_select()->next_select() && 
+    first_select()->next_select()->linkage == UNION_TYPE;
+}
+
 #define ALTER_ADD_COLUMN	1
 #define ALTER_DROP_COLUMN	2
 #define ALTER_CHANGE_COLUMN	4

sql/sql_view.cc

@@ -1263,13 +1263,18 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table,
         unit->slave= save_slave; // fix include_down initialisation
       }
 
+      /* 
+        We can safely ignore the VIEW's ORDER BY if we merge into union 
+        branch, as order is not important there.
+      */
+      if (!table->select_lex->master_unit()->is_union())
+        table->select_lex->order_list.push_back(&lex->select_lex.order_list);
       /*
 	This SELECT_LEX will be linked in global SELECT_LEX list
 	to make it processed by mysql_handle_derived(),
 	but it will not be included to SELECT_LEX tree, because it
 	will not be executed
-      */
-      table->select_lex->order_list.push_back(&lex->select_lex.order_list);
+      */ 
       goto ok;
     }