MDEV-4974: memory leak in 5.5.32-MariaDB-1~wheezy-log

- When a JOIN has both "optimization tabs" (JOIN_TABs used to 
  read the base tables and do the join operation) and also
  has "execution tabs" (a JOIN_TAB that is to produce result set 
  that is sent to the client), do not forget to call JOIN_TAB::cleanup()
  for the execution JOIN_TAB.

mysql-test/r/order_by.result

@@ -2026,4 +2026,28 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	8	Using index
 1	SIMPLE	t2	ref	i_a	i_a	5	test.t1.a	2	Using index
 DROP TABLE t1,t2;
+#
+# MDEV-4974 memory leak in 5.5.32-MariaDB-1~wheezy-log
+#
+set sort_buffer_size=default;
+set max_sort_length=default;
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2 (b int,
+col1 varchar(255),
+col2 varchar(255)
+) character set utf8;
+insert into t2 select 
+A.a+10*B.a,
+concat('wow-wow-col1-value-', A.a+10*B.a+100*C.a),
+concat('wow-wow-col2-value-', A.a+10*B.a+100*C.a)
+from 
+t1 A, t1 B, t1 C where C.a < 8;
+create table t3 as 
+select distinct A.col1 as XX, B.col1 as YY
+from 
+t2 A, t2 B 
+where A.b = B.b
+order by A.col2, B.col2 limit 10, 1000000;
+drop table t1,t2,t3;
 End of 5.5 tests

mysql-test/t/order_by.test

@@ -1717,6 +1717,35 @@ SELECT t1.a FROM t1 LEFT JOIN t2 ON t1.a=t2.a ORDER BY t1.a LIMIT 100;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # MDEV-4974 memory leak in 5.5.32-MariaDB-1~wheezy-log
+--echo #
+set sort_buffer_size=default;
+set max_sort_length=default;
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+create table t2 (b int,
+                 col1 varchar(255),
+                 col2 varchar(255)
+                 ) character set utf8;
+
+insert into t2 select 
+  A.a+10*B.a,
+  concat('wow-wow-col1-value-', A.a+10*B.a+100*C.a),
+  concat('wow-wow-col2-value-', A.a+10*B.a+100*C.a)
+from 
+  t1 A, t1 B, t1 C where C.a < 8;
+
+create table t3 as 
+select distinct A.col1 as XX, B.col1 as YY
+from 
+   t2 A, t2 B 
+where A.b = B.b
+order by A.col2, B.col2 limit 10, 1000000;
+
+drop table t1,t2,t3;
+
 --echo End of 5.5 tests
 
 

sql/sql_select.cc

@@ -10819,6 +10819,16 @@ void JOIN::cleanup(bool full)
         {
           tab->cleanup();
         }
+
+        if (tabs_kind == WALK_OPTIMIZATION_TABS && 
+            first_breadth_first_tab(this, WALK_OPTIMIZATION_TABS) != 
+            first_breadth_first_tab(this, WALK_EXECUTION_TABS))
+        {
+          JOIN_TAB *jt= first_breadth_first_tab(this, WALK_EXECUTION_TABS);
+          /* We've walked optimization tabs. do execution ones too */
+          if (jt)
+            jt->cleanup();
+        }
       }
       cleaned= true;