Bug #21180: Subselect with index for both WHERE and ORDER BY produces empty result

 Reseting subqueries with "quick" access methods was incomplete.
 Partially backported the correct reseting of QUICK_SELECTs from 5.x.

mysql-test/r/subselect.result

@@ -2895,3 +2895,32 @@ select * from t1 where NOT(s1 = ALL (select s1/s1 from t1));
 s1
 2
 drop table t1;
+create table t1(a int, primary key (a));
+insert into t1 values (10);
+create table t2 (a int primary key, b varchar(32), c int, unique key b(c, b));
+insert into t2(a, c, b) values (1,10,'359'), (2,10,'35988'), (3,10,'35989');
+explain SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+ORDER BY t2.c DESC, t2.b DESC LIMIT 1) WHERE t1.a = 10;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	PRIMARY	NULL	NULL	NULL	1	
+1	PRIMARY	r	const	PRIMARY	PRIMARY	4	const	1	
+2	DEPENDENT SUBQUERY	t2	range	b	b	38	NULL	2	Using where
+SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+ORDER BY t2.c DESC, t2.b DESC LIMIT 1) WHERE t1.a = 10;
+a	a	b
+10	3	35989
+explain SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+ORDER BY t2.c, t2.b LIMIT 1) WHERE t1.a = 10;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	PRIMARY	NULL	NULL	NULL	1	
+1	PRIMARY	r	const	PRIMARY	PRIMARY	4	const	1	
+2	DEPENDENT SUBQUERY	t2	range	b	b	38	NULL	2	Using where
+SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+ORDER BY t2.c, t2.b LIMIT 1) WHERE t1.a = 10;
+a	a	b
+10	1	359
+drop table t1,t2;

mysql-test/t/subselect.test

@@ -1861,4 +1861,30 @@ select * from t1 where NOT(s1+1 = ANY (select s1 from t1));
 select * from t1 where (s1 = ALL (select s1/s1 from t1));
 select * from t1 where NOT(s1 = ALL (select s1/s1 from t1));
 drop table t1;
+
+#
+# Bug #21180: Subselect with index for both WHERE and ORDER BY 
+#             produces empty result
+#
+create table t1(a int, primary key (a));
+insert into t1 values (10);
+
+create table t2 (a int primary key, b varchar(32), c int, unique key b(c, b));
+insert into t2(a, c, b) values (1,10,'359'), (2,10,'35988'), (3,10,'35989');
+
+explain SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+  ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+             ORDER BY t2.c DESC, t2.b DESC LIMIT 1) WHERE t1.a = 10;
+SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+  ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+            ORDER BY t2.c DESC, t2.b DESC LIMIT 1) WHERE t1.a = 10;
+
+explain SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+  ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+            ORDER BY t2.c, t2.b LIMIT 1) WHERE t1.a = 10;
+SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r 
+  ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899' 
+            ORDER BY t2.c, t2.b LIMIT 1) WHERE t1.a = 10;
+
+drop table t1,t2;
 # End of 4.1 tests

sql/opt_range.cc

@@ -2980,6 +2980,14 @@ int QUICK_SELECT::get_next()
   }
 }
 
+void QUICK_SELECT::reset(void) 
+{
+  next= 0; 
+  it.rewind();
+  range= 0; 
+  if (file->inited == handler::NONE) 
+    file->ha_index_init(index);
+}
 
 /* Get next for geometrical indexes */
 
@@ -3201,7 +3209,11 @@ bool QUICK_SELECT_DESC::test_if_null_range(QUICK_RANGE *range_arg,
   return 0;
 }
 #endif
-
+void QUICK_SELECT_DESC::reset(void)
+{ 
+  rev_it.rewind();
+  QUICK_SELECT::reset();
+}
 
 /*****************************************************************************
 ** Print a quick range for debugging

sql/opt_range.h

@@ -86,7 +86,7 @@ public:
 
   QUICK_SELECT(THD *thd, TABLE *table,uint index_arg,bool no_alloc=0);
   virtual ~QUICK_SELECT();
-  void reset(void) { next=0; it.rewind(); }
+  virtual void reset(void);
   int init()
   {
     key_part_info= head->key_info[index].key_part;
@@ -120,7 +120,7 @@ private:
 #ifdef NOT_USED
   bool test_if_null_range(QUICK_RANGE *range, uint used_key_parts);
 #endif
-  void reset(void) { next=0; rev_it.rewind(); }
+  void reset(void);
   List<QUICK_RANGE> rev_ranges;
   List_iterator<QUICK_RANGE> rev_it;
 };