Fixed LP bug #877316.

This bug happened due to incompleteness of the fix for bug 872735:
the occurrences of the fields in the conditions of correlated
subqueries were not taken into account when recalculating
covering keys bit maps.

mysql-test/r/derived_view.result

@@ -1504,4 +1504,34 @@ a	b	c
 20	r	r
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
+#
+# LP bug #877316: query over a view with correlated subquery in WHERE
+#
+CREATE TABLE t1 (a int, b int, PRIMARY KEY (a)) ;
+INSERT INTO t1 VALUES (18,2), (19,9);
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES (10,8), (5,10);
+CREATE VIEW v1 AS SELECT * FROM t1;
+SELECT t1.a FROM t1
+WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < t1.b);
+a
+19
+EXPLAIN
+SELECT t1.a FROM t1
+WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < t1.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+SELECT v1.a FROM v1
+WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < v1.b);
+a
+19
+EXPLAIN
+SELECT v1.a FROM v1
+WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < v1.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+DROP VIEW v1;
+DROP TABLE t1,t2;
 set optimizer_switch=@exit_optimizer_switch;

mysql-test/t/derived_view.test

@@ -946,6 +946,32 @@ SELECT * FROM t3
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
 
+--echo #
+--echo # LP bug #877316: query over a view with correlated subquery in WHERE
+--echo #
+
+CREATE TABLE t1 (a int, b int, PRIMARY KEY (a)) ;
+INSERT INTO t1 VALUES (18,2), (19,9);
+
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES (10,8), (5,10);
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+
+SELECT t1.a FROM t1
+  WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < t1.b);
+EXPLAIN
+SELECT t1.a FROM t1
+  WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < t1.b);
+
+SELECT v1.a FROM v1
+  WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < v1.b);
+EXPLAIN
+SELECT v1.a FROM v1
+  WHERE EXISTS (SELECT t2.a FROM t2 WHERE t2.b < v1.b);
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
 
 # The following command must be the last one the file 
 set optimizer_switch=@exit_optimizer_switch;

sql/item.cc

@@ -2172,6 +2172,12 @@ bool Item_field::enumerate_field_refs_processor(uchar *arg)
   return FALSE;
 }
 
+bool Item_field::covering_keys_processor(uchar *arg)
+{
+  if (field && field->table)
+    field->table->covering_keys.intersect(field->part_of_key);
+  return FALSE;
+}
 
 const char *Item_ident::full_name() const
 {

sql/item.h

@@ -1018,6 +1018,7 @@ public:
   virtual bool mark_as_eliminated_processor(uchar *arg) { return 0; }
   virtual bool eliminate_subselect_processor(uchar *arg) { return 0; }
   virtual bool set_fake_select_as_master_processor(uchar *arg) { return 0; }
+  virtual bool covering_keys_processor(uchar *arg) { return 0; }
   virtual bool view_used_tables_processor(uchar *arg) { return 0; }
   virtual bool eval_not_null_tables(uchar *opt_arg) { return 0; }
   virtual bool clear_sum_processor(uchar *opt_arg) { return 0; }
@@ -1832,6 +1833,7 @@ public:
   bool vcol_in_partition_func_processor(uchar *bool_arg);
   bool check_vcol_func_processor(uchar *arg) { return FALSE;}
   bool enumerate_field_refs_processor(uchar *arg);
+  bool covering_keys_processor(uchar *arg);
   void cleanup();
   Item_equal *get_item_equal() { return item_equal; }
   void set_item_equal(Item_equal *item_eq) { item_equal= item_eq; }

sql/item_subselect.cc

@@ -492,6 +492,7 @@ void Item_subselect::recalc_used_tables(st_select_lex *new_parent,
           upper->item->walk(&Item::enumerate_field_refs_processor, FALSE,
                             (uchar*)&fixer);
           used_tables_cache |= fixer.used_tables;
+          upper->item->walk(&Item::covering_keys_processor, FALSE, NULL);
 /*
           if (after_pullout)
             upper->item->fix_after_pullout(new_parent, &(upper->item));