Merge gkodinov@bk-internal.mysql.com:/home/bk/mysql-5.1-runtime

into  magare.gmz:/home/kgeorge/mysql/autopush/B31974-5.1-runtime

mysql-test/r/group_min_max.result

@@ -2251,7 +2251,7 @@ EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-2	SUBQUERY	t1	range	NULL	a	5	NULL	8	
+2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -2268,7 +2268,7 @@ AND t1_outer1.b = t1_outer2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer1	ref	a	a	5	const	1	Using where; Using index
 1	PRIMARY	t1_outer2	index	NULL	a	10	NULL	15	Using where; Using index; Using join buffer
-2	SUBQUERY	t1	range	NULL	a	5	NULL	8	
+2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
 EXPLAIN SELECT (SELECT (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) x
 FROM t1 AS t1_outer) x2 FROM t1 AS t1_outer2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/r/index_merge_myisam.result

@@ -286,7 +286,7 @@ NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL
 explain select * from (select * from t1 where key1 = 3 or key2 =3) as Z where key8 >5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
-2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where
+2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where; Using index
 create table t3 like t0;
 insert into t3 select * from t0;
 alter table t3 add key9 int not null, add index i9(key9);

mysql-test/r/key.result

@@ -545,3 +545,17 @@ c1
 1
 1
 DROP TABLE t1;
+CREATE TABLE t1 (a INT, b INT, INDEX (a,b));
+INSERT INTO t1 (a, b)
+VALUES
+(1,1), (1,2), (1,3), (1,4), (1,5),
+(2,2), (2,3), (2,1), (3,1), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6);
+EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
+(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
+SELECT 1 as RES FROM t1 AS t1_outer WHERE 
+(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
+RES
+DROP TABLE t1;

mysql-test/t/key.test

@@ -524,3 +524,20 @@ ORDER BY (
   LIMIT 1);
 
 DROP TABLE t1;
+
+
+#
+# Bug #31974: Wrong EXPLAIN output
+#
+
+CREATE TABLE t1 (a INT, b INT, INDEX (a,b));
+INSERT INTO t1 (a, b)
+   VALUES
+     (1,1), (1,2), (1,3), (1,4), (1,5),
+     (2,2), (2,3), (2,1), (3,1), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6);
+EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
+  (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
+SELECT 1 as RES FROM t1 AS t1_outer WHERE 
+  (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
+
+DROP TABLE t1;

sql/sql_select.cc

@@ -6651,14 +6651,7 @@ void JOIN::cleanup(bool full)
       for (tab= join_tab, end= tab+tables; tab != end; tab++)
       {
 	if (tab->table)
-        {
-          if (tab->table->key_read)
-          {
-            tab->table->key_read= 0;
-            tab->table->file->extra(HA_EXTRA_NO_KEYREAD);
-          }
           tab->table->file->ha_index_or_rnd_end();
-        }
       }
     }
   }