fixed cleanup of result object of subqueries. (BUG#8125)

mysql-test/r/subselect.result:
  cleaning up of results of subselects test
mysql-test/t/subselect.test:
  cleaning up of results of subselects test
sql/item_subselect.cc:
  call result object cleupup on engine cleunup
sql/sql_class.cc:
  added cleanup of select_max_min_finder_subselect
sql/sql_class.h:
  added cleanup of select_max_min_finder_subselect

mysql-test/r/subselect.result

@@ -2196,3 +2196,15 @@ ERROR 42S22: Reference 'xx' not supported (forward reference in item list)
 select 1 = ALL (select 1 from t1 where 1 = xx ), 1 as xx from DUAL;
 ERROR 42S22: Reference 'xx' not supported (forward reference in item list)
 drop table t1;
+CREATE TABLE `t1` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY  (`a`,`b`,`c`)) ENGINE=InnoDB;
+CREATE TABLE t2 LIKE t1;
+INSERT INTO t1 VALUES (1,1,1);
+INSERT INTO t2 VALUES (1,1,1);
+PREPARE my_stmt FROM "SELECT t1.b, count(*) FROM t1 group by t1.b having
+count(*) > ALL (SELECT COUNT(*) FROM t2 WHERE t2.a=1 GROUP By t2.b)";
+EXECUTE my_stmt;
+b	count(*)
+EXECUTE my_stmt;
+b	count(*)
+deallocate prepare my_stmt;
+drop table t1,t2;

mysql-test/t/subselect.test

@@ -1465,3 +1465,17 @@ select 1 = ALL (select 1 from t1 where 1 = xx ), 1 as xx;
 -- error 1247
 select 1 = ALL (select 1 from t1 where 1 = xx ), 1 as xx from DUAL;
 drop table t1;
+
+#
+# cleaning up of results of subselects (BUG#8125)
+#
+CREATE TABLE `t1` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY  (`a`,`b`,`c`)) ENGINE=InnoDB;
+CREATE TABLE t2 LIKE t1;
+INSERT INTO t1 VALUES (1,1,1);
+INSERT INTO t2 VALUES (1,1,1);
+PREPARE my_stmt FROM "SELECT t1.b, count(*) FROM t1 group by t1.b having
+count(*) > ALL (SELECT COUNT(*) FROM t2 WHERE t2.a=1 GROUP By t2.b)";
+EXECUTE my_stmt;
+EXECUTE my_stmt;
+deallocate prepare my_stmt;
+drop table t1,t2;

sql/item_subselect.cc

@@ -1127,6 +1127,7 @@ void subselect_single_select_engine::cleanup()
   DBUG_ENTER("subselect_single_select_engine::cleanup");
   prepared= optimized= executed= 0;
   join= 0;
+  result->cleanup();
   DBUG_VOID_RETURN;
 }
 
@@ -1135,6 +1136,7 @@ void subselect_union_engine::cleanup()
 {
   DBUG_ENTER("subselect_union_engine::cleanup");
   unit->reinit_exec_mechanism();
+  result->cleanup();
   DBUG_VOID_RETURN;
 }
 
@@ -1142,6 +1144,10 @@ void subselect_union_engine::cleanup()
 void subselect_uniquesubquery_engine::cleanup()
 {
   DBUG_ENTER("subselect_uniquesubquery_engine::cleanup");
+  /*
+    subselect_uniquesubquery_engine have not 'result' assigbed, so we do not
+    cleanup() it
+  */
   DBUG_VOID_RETURN;
 }
 

sql/sql_class.cc

@@ -1240,6 +1240,14 @@ bool select_singlerow_subselect::send_data(List<Item> &items)
 }
 
 
+void select_max_min_finder_subselect::cleanup()
+{
+  DBUG_ENTER("select_max_min_finder_subselect::cleanup");
+  cache= 0;
+  DBUG_VOID_RETURN;
+}
+
+
 bool select_max_min_finder_subselect::send_data(List<Item> &items)
 {
   DBUG_ENTER("select_max_min_finder_subselect::send_data");

sql/sql_class.h

@@ -1381,6 +1381,7 @@ class select_max_min_finder_subselect :public select_subselect
   select_max_min_finder_subselect(Item_subselect *item, bool mx)
     :select_subselect(item), cache(0), fmax(mx)
   {}
+  void cleanup();
   bool send_data(List<Item> &items);
   bool cmp_real();
   bool cmp_int();