Fixed LP bug #809206.

The bitmap of used tables must be evaluated for the select list of every
materialized derived table / view and saved in a dedicated field.
This is also applied to materialized subqueries.

mysql-test/r/derived_view.result

@@ -946,7 +946,7 @@ DROP TABLE t1,t2,t3;
 # LP bug #806504: right join over a view/derived table           
 #
 CREATE TABLE t1 (a int, b int) ;
-INSERT IGNORE INTO t1 VALUES (0,0);
+INSERT INTO t1 VALUES (0,0);
 CREATE TABLE t2 (a int) ;
 INSERT INTO t2 VALUES (0), (0);
 CREATE VIEW v1 AS SELECT * FROM t1;
@@ -978,3 +978,49 @@ Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
 DROP VIEW v1;
 DROP TABLE t1,t2;
+#
+# LP bug #809206: DISTINCT in derived table / view           
+#
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (0);
+CREATE TABLE t2 (a  varchar(32), b int, KEY (a)) ;
+INSERT INTO t2 VALUES
+('j',28), ('c',29), ('i',26), ('c',29), ('k',27),
+('j',28), ('c',29), ('i',25), ('d',26), ('k',27);
+CREATE TABLE t3 (a varchar(32));
+INSERT INTO t3 VALUES ('j'), ('c');
+CREATE VIEW v1 AS SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+b
+28
+29
+EXPLAIN 
+SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	Using temporary
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	ref	a	a	35	test.t3.a	2	
+SELECT * FROM (SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a) t;
+b
+28
+29
+EXPLAIN
+SELECT * FROM (SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a) t;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
+2	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	Using temporary
+2	DERIVED	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DERIVED	t2	ref	a	a	35	test.t3.a	2	
+SELECT * FROM v1;
+b
+28
+29
+EXPLAIN 
+SELECT * FROM v1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
+2	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	Using temporary
+2	DERIVED	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DERIVED	t2	ref	a	a	35	test.t3.a	2	
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;

mysql-test/r/func_gconcat.result

@@ -985,8 +985,8 @@ EXPLAIN EXTENDED SELECT 1 FROM
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	100.00	Using join buffer (flat, BNL join)
-2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort; Distinct
-2	DERIVED	td	ALL	NULL	NULL	NULL	NULL	2	100.00	Distinct; Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+2	DERIVED	td	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
 Warnings:
 Note	1003	select 1 AS `1` from (select distinct group_concat(`test`.`td`.`f1` separator ',') AS `GROUP_CONCAT(td.f1)` from `test`.`t1` join `test`.`t1` `td` group by `test`.`td`.`f1`) `d` join `test`.`t1`
 SELECT 1 FROM

mysql-test/t/derived_view.test

@@ -537,7 +537,7 @@ DROP TABLE t1,t2,t3;
 --echo #
 
 CREATE TABLE t1 (a int, b int) ;
-INSERT IGNORE INTO t1 VALUES (0,0);
+INSERT INTO t1 VALUES (0,0);
 
 CREATE TABLE t2 (a int) ;
 INSERT INTO t2 VALUES (0), (0);
@@ -558,3 +558,35 @@ SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 
 DROP VIEW v1;
 DROP TABLE t1,t2;
+
+--echo #
+--echo # LP bug #809206: DISTINCT in derived table / view           
+--echo #
+
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (0);
+
+CREATE TABLE t2 (a  varchar(32), b int, KEY (a)) ;
+INSERT INTO t2 VALUES
+  ('j',28), ('c',29), ('i',26), ('c',29), ('k',27),
+  ('j',28), ('c',29), ('i',25), ('d',26), ('k',27);
+
+CREATE TABLE t3 (a varchar(32));
+INSERT INTO t3 VALUES ('j'), ('c');
+
+CREATE VIEW v1 AS SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+
+SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+EXPLAIN 
+SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a;
+
+SELECT * FROM (SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a) t;
+EXPLAIN
+SELECT * FROM (SELECT DISTINCT t2.b FROM t1,t2,t3 WHERE t3.a = t2.a) t;
+
+SELECT * FROM v1;
+EXPLAIN 
+SELECT * FROM v1;
+
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;

sql/sql_lex.cc

@@ -3511,7 +3511,6 @@ void SELECT_LEX::update_used_tables()
   while ((item= it++))
   {
     item->update_used_tables();
-    join->thd->used_tables|= item->used_tables();
   }
   Item_outer_ref *ref;
   List_iterator_fast<Item_outer_ref> ref_it(inner_refs_list);
@@ -3519,7 +3518,6 @@ void SELECT_LEX::update_used_tables()
   {
     item= ref->outer_ref;
     item->update_used_tables();
-    join->thd->used_tables|= item->used_tables();
   }
   for (ORDER *order= group_list.first; order; order= order->next)
     (*order->item)->update_used_tables();

sql/sql_select.cc

@@ -880,8 +880,6 @@ JOIN::optimize()
 
   if (select_lex->first_cond_optimization)
   {
-    if (!select_lex->outer_select())
-      thd->used_tables= 0; 
     //Do it only for the first execution
     /* Merge all mergeable derived tables/views in this SELECT. */
     if (select_lex->handle_derived(thd->lex, DT_MERGE))
@@ -895,8 +893,6 @@ JOIN::optimize()
 
   if (select_lex->first_cond_optimization)
   {
-    if (!select_lex->outer_select())
-      thd->used_tables= 0;
     /* dump_TABLE_LIST_graph(select_lex, select_lex->leaf_tables); */
     if (convert_join_subqueries_to_semijoins(this))
       DBUG_RETURN(1); /* purecov: inspected */
@@ -906,6 +902,7 @@ JOIN::optimize()
     /* Save this info for the next executions */
     if (select_lex->save_leaf_tables(thd))
       DBUG_RETURN(1);
+    eval_select_list_used_tables();
   }
   
   table_count= select_lex->leaf_tables.elements;
@@ -1727,7 +1724,7 @@ int JOIN::init_execution()
 
     if (exec_tmp_table1->distinct)
     {
-      table_map used_tables= thd->used_tables;
+      table_map used_tables= select_list_used_tables;
       JOIN_TAB *last_join_tab= join_tab + top_join_tab_count - 1;
       do
       {
@@ -8464,6 +8461,30 @@ void JOIN::drop_unused_derived_keys()
   }
 }
 
+
+/*
+  Evaluate the bitmap of used tables for items from the select list
+*/
+
+inline void JOIN::eval_select_list_used_tables()
+{
+  select_list_used_tables= 0;
+  Item *item;
+  List_iterator_fast<Item> it(fields_list);
+  while ((item= it++))
+  {
+    select_list_used_tables|= item->used_tables();
+  }
+  Item_outer_ref *ref;
+  List_iterator_fast<Item_outer_ref> ref_it(select_lex->inner_refs_list);
+  while ((ref= ref_it++))
+  {
+    item= ref->outer_ref;
+    select_list_used_tables|= item->used_tables();
+  }
+}
+
+
 /*
   Determine {after which table we'll produce ordered set} 
 
@@ -20845,7 +20866,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 	  need_order=0;
 	  extra.append(STRING_WITH_LEN("; Using filesort"));
 	}
-	if (distinct & test_all_bits(used_tables,thd->used_tables))
+	if (distinct & test_all_bits(used_tables,
+                                     join->select_list_used_tables))
 	  extra.append(STRING_WITH_LEN("; Distinct"));
         if (tab->loosescan_match_tab)
         {

sql/sql_select.h

@@ -767,6 +767,8 @@ public:
      make_join_statistics)
   */
   table_map outer_join;
+  /* Bitmap of tables used in the select list items */
+  table_map select_list_used_tables;
   ha_rows  send_records,found_records,examined_rows,row_limit, select_limit;
   /**
     Used to fetch no more than given amount of rows per one
@@ -1134,6 +1136,7 @@ public:
     return (table_map(1) << table_count) - 1;
   }
   void drop_unused_derived_keys();
+  inline void eval_select_list_used_tables();
   /* 
     Return the table for which an index scan can be used to satisfy 
     the sort order needed by the ORDER BY/(implicit) GROUP BY clause