Merge 5.3->5.5

mysql-test/r/join_outer.result

@@ -1930,7 +1930,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
-Note	1003	select NULL AS `a` from `test`.`t2`
+Note	1003	select NULL AS `a` from `test`.`t2` where 1
 DROP TABLE t1,t2,t3;
 #
 # LP bug #817384 Wrong result with outer join + subquery in ON
@@ -2150,4 +2150,18 @@ INSERT INTO t2 VALUES (3,'2000-03-06'), (4,'2007-09-25');
 SELECT * FROM t1 LEFT JOIN t2 ON i1 = i2 WHERE d1 IS NULL AND d2 IS NULL;
 i1	d1	i2	d2
 DROP TABLE t1,t2;
+#
+# Bug mdev-4952: LEFT JOIN with disjunctive 
+#                <non-nullable datetime field> IS NULL in WHERE 
+#                causes an assert failure  
+#
+CREATE TABLE t1 (a1 int, b1 int NOT NULL) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1, 10), (2, 11);
+CREATE TABLE t2 (dt datetime NOT NULL, a2 int, b2 int) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+('2006-10-08 09:34:54', 1, 100), ('2001-01-19 01:04:43', 2, 200);
+SELECT * FROM t1 LEFT JOIN t2 ON a1 = a2
+WHERE ( dt IS NULL OR FALSE ) AND b2 IS NULL;
+a1	b1	dt	a2	b2
+DROP TABLE t1,t2;
 SET optimizer_switch=@save_optimizer_switch;

mysql-test/r/join_outer_jcl6.result

@@ -1941,7 +1941,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
-Note	1003	select NULL AS `a` from `test`.`t2`
+Note	1003	select NULL AS `a` from `test`.`t2` where 1
 DROP TABLE t1,t2,t3;
 #
 # LP bug #817384 Wrong result with outer join + subquery in ON
@@ -2161,6 +2161,20 @@ INSERT INTO t2 VALUES (3,'2000-03-06'), (4,'2007-09-25');
 SELECT * FROM t1 LEFT JOIN t2 ON i1 = i2 WHERE d1 IS NULL AND d2 IS NULL;
 i1	d1	i2	d2
 DROP TABLE t1,t2;
+#
+# Bug mdev-4952: LEFT JOIN with disjunctive 
+#                <non-nullable datetime field> IS NULL in WHERE 
+#                causes an assert failure  
+#
+CREATE TABLE t1 (a1 int, b1 int NOT NULL) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1, 10), (2, 11);
+CREATE TABLE t2 (dt datetime NOT NULL, a2 int, b2 int) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+('2006-10-08 09:34:54', 1, 100), ('2001-01-19 01:04:43', 2, 200);
+SELECT * FROM t1 LEFT JOIN t2 ON a1 = a2
+WHERE ( dt IS NULL OR FALSE ) AND b2 IS NULL;
+a1	b1	dt	a2	b2
+DROP TABLE t1,t2;
 SET optimizer_switch=@save_optimizer_switch;
 set join_cache_level=default;
 show variables like 'join_cache_level';

mysql-test/r/select.result

@@ -4786,7 +4786,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1`
+Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1` where 1
 EXPLAIN EXTENDED SELECT * FROM t1 WHERE a > UNIX_TIMESTAMP('2009-03-10 00:00:00');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
@@ -5425,4 +5425,23 @@ Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,'k' AS `c`,'k' AS
 SELECT * FROM t1, t2 WHERE c=b AND (1=2 OR ((b='h' OR a=136) AND d=b));
 a	b	c	d
 DROP TABLE t1,t2;
+#
+# Bug mdev-4944: range conditition in OR formula with fields
+#                belonging to multiple equalities 
+#
+CREATE TABLE t1 (i1 int, j1 int) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,8);
+CREATE TABLE t2 (i2 int, INDEX idx (i2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (8), (9);
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+Warnings:
+Note	1003	select 1 AS `i1`,8 AS `j1`,`test`.`t2`.`i2` AS `i2` from `test`.`t2` where 0
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+i1	j1	i2
+DROP TABLE t1,t2;
 End of 5.3 tests

mysql-test/r/select_jcl6.result

@@ -4797,7 +4797,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1`
+Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1` where 1
 EXPLAIN EXTENDED SELECT * FROM t1 WHERE a > UNIX_TIMESTAMP('2009-03-10 00:00:00');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
@@ -5436,6 +5436,25 @@ Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,'k' AS `c`,'k' AS
 SELECT * FROM t1, t2 WHERE c=b AND (1=2 OR ((b='h' OR a=136) AND d=b));
 a	b	c	d
 DROP TABLE t1,t2;
+#
+# Bug mdev-4944: range conditition in OR formula with fields
+#                belonging to multiple equalities 
+#
+CREATE TABLE t1 (i1 int, j1 int) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,8);
+CREATE TABLE t2 (i2 int, INDEX idx (i2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (8), (9);
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+Warnings:
+Note	1003	select 1 AS `i1`,8 AS `j1`,`test`.`t2`.`i2` AS `i2` from `test`.`t2` where 0
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+i1	j1	i2
+DROP TABLE t1,t2;
 End of 5.3 tests
 set join_cache_level=default;
 show variables like 'join_cache_level';

mysql-test/r/select_pkeycache.result

@@ -4786,7 +4786,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
 Warnings:
-Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1`
+Note	1003	select 2 AS `b`,`test`.`t1`.`a` AS `a` from `test`.`t1` where 1
 EXPLAIN EXTENDED SELECT * FROM t1 WHERE a > UNIX_TIMESTAMP('2009-03-10 00:00:00');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
@@ -5425,4 +5425,23 @@ Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,'k' AS `c`,'k' AS
 SELECT * FROM t1, t2 WHERE c=b AND (1=2 OR ((b='h' OR a=136) AND d=b));
 a	b	c	d
 DROP TABLE t1,t2;
+#
+# Bug mdev-4944: range conditition in OR formula with fields
+#                belonging to multiple equalities 
+#
+CREATE TABLE t1 (i1 int, j1 int) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,8);
+CREATE TABLE t2 (i2 int, INDEX idx (i2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (8), (9);
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+Warnings:
+Note	1003	select 1 AS `i1`,8 AS `j1`,`test`.`t2`.`i2` AS `i2` from `test`.`t2` where 0
+SELECT * FROM t1, t2 
+WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+i1	j1	i2
+DROP TABLE t1,t2;
 End of 5.3 tests

mysql-test/r/subselect.result

@@ -1319,7 +1319,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)

mysql-test/r/subselect4.result

@@ -1750,7 +1750,7 @@ SET @@optimizer_switch = 'in_to_exists=on,materialization=off,semijoin=off';
 EXPLAIN SELECT * FROM t1 WHERE a1 IN (SELECT b1 FROM t2 WHERE b1 = b2);
 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	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT * FROM t1 WHERE a1 IN (SELECT b1 FROM t2 WHERE b1 = b2);
 a1	a2
 set @@optimizer_switch=@save_optimizer_switch;

mysql-test/r/subselect_no_mat.result

@@ -1326,7 +1326,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)

mysql-test/r/subselect_no_opts.result

@@ -1322,7 +1322,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)

mysql-test/r/subselect_no_scache.result

@@ -1325,7 +1325,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)

mysql-test/r/subselect_no_semijoin.result

@@ -1322,7 +1322,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from dual where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)

mysql-test/r/table_elim.result

@@ -17,7 +17,7 @@ explain extended select t1.a from t1 left join t2 on t2.a=t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where 1
 select t1.a from t1 left join t2 on t2.a=t1.a;
 a
 0
@@ -62,7 +62,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	4	100.00	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t0` left join (`test`.`t1`) on((`test`.`t1`.`a` = `test`.`t0`.`a`))
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t0` left join (`test`.`t1`) on((`test`.`t1`.`a` = `test`.`t0`.`a`)) where 1
 # Elimination with aggregate functions
 explain select count(*) from t1 left join t2 on t2.a=t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -626,7 +626,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	b	5	NULL	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`b` AS `b` from `test`.`t2` where <expr_cache><`test`.`t2`.`b`>(<in_optimizer>(`test`.`t2`.`b`,<exists>(select sum(1) from dual having (<cache>(`test`.`t2`.`b`) = <ref_null_helper>(sum(1))))))
+Note	1003	select `test`.`t2`.`b` AS `b` from `test`.`t2` where <expr_cache><`test`.`t2`.`b`>(<in_optimizer>(`test`.`t2`.`b`,<exists>(select sum(1) from dual where 1 having (<cache>(`test`.`t2`.`b`) = <ref_null_helper>(sum(1))))))
 DROP TABLE t1,t2;
 #
 # MDEV-4840: Wrong result (missing rows) on LEFT JOIN with InnoDB tables

mysql-test/t/join_outer.test

@@ -1703,4 +1703,22 @@ SELECT * FROM t1 LEFT JOIN t2 ON i1 = i2 WHERE d1 IS NULL AND d2 IS NULL;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # Bug mdev-4952: LEFT JOIN with disjunctive 
+--echo #                <non-nullable datetime field> IS NULL in WHERE 
+--echo #                causes an assert failure  
+--echo #
+
+CREATE TABLE t1 (a1 int, b1 int NOT NULL) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1, 10), (2, 11);
+
+CREATE TABLE t2 (dt datetime NOT NULL, a2 int, b2 int) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+('2006-10-08 09:34:54', 1, 100), ('2001-01-19 01:04:43', 2, 200);
+
+SELECT * FROM t1 LEFT JOIN t2 ON a1 = a2
+  WHERE ( dt IS NULL OR FALSE ) AND b2 IS NULL;
+
+DROP TABLE t1,t2;
+
 SET optimizer_switch=@save_optimizer_switch;

mysql-test/t/select.test

@@ -4563,5 +4563,24 @@ SELECT * FROM t1, t2 WHERE c=b AND (1=2 OR ((b='h' OR a=136) AND d=b));
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # Bug mdev-4944: range conditition in OR formula with fields
+--echo #                belonging to multiple equalities 
+--echo #
+
+CREATE TABLE t1 (i1 int, j1 int) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,8);
+
+CREATE TABLE t2 (i2 int, INDEX idx (i2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (8), (9);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2 
+  WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+SELECT * FROM t1, t2 
+  WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
+
+DROP TABLE t1,t2;
+
 --echo End of 5.3 tests
 

sql/sql_select.cc

@@ -1262,17 +1262,12 @@ JOIN::optimize()
     conds=new Item_int((longlong) 1,1);	// Always true
   }
 
-  if (const_tables && conds)
+  if (impossible_where)
   {
-    conds= remove_eq_conds(thd, conds, &cond_value);
-    if (cond_value == Item::COND_FALSE)
-    {
-      zero_result_cause=
-        "Impossible WHERE noticed after reading const tables";
-      select_lex->mark_const_derived(zero_result_cause);
-      conds=new Item_int((longlong) 0,1);
-      goto setup_subq_exit;
-    }
+    zero_result_cause=
+      "Impossible WHERE noticed after reading const tables";
+    select_lex->mark_const_derived(zero_result_cause);
+    goto setup_subq_exit;
   }
 
   select= make_select(*table, const_table_map,
@@ -3598,6 +3593,18 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
     }
   }
 
+  join->impossible_where= false;
+  if (conds && const_count)
+  { 
+    conds= remove_eq_conds(join->thd, conds, &join->cond_value);
+    if (join->cond_value == Item::COND_FALSE)
+    {
+      join->impossible_where= true;
+      conds=new Item_int((longlong) 0,1);
+    }
+    join->conds= conds;      
+  }
+
   /* Calc how many (possible) matched records in each table */
 
   for (s=stat ; s < stat_end ; s++)
@@ -13692,7 +13699,20 @@ internal_remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
         }
         else
 	{
-          li.replace(new_item);
+          if (new_item->type() == Item::COND_ITEM &&
+              ((Item_cond*) new_item)->functype() == 
+              ((Item_cond*) cond)->functype())
+	  {
+	    List<Item> *new_item_arg_list=
+              ((Item_cond *) new_item)->argument_list();
+            uint cnt= new_item_arg_list->elements;
+            li.replace(*new_item_arg_list);
+            /* Make iterator li ignore new items */
+            for (cnt--; cnt; cnt--)
+              li++;
+          }
+          else
+            li.replace(new_item);
           should_fix_fields= 1;
         } 
       }   

sql/sql_select.h

@@ -1160,6 +1160,11 @@ public:
   bool cleaned;
   DYNAMIC_ARRAY keyuse;
   Item::cond_result cond_value, having_value;
+  /**
+    Impossible where after reading const tables 
+    (set in make_join_statistics())
+  */
+  bool impossible_where; 
   List<Item> all_fields; ///< to store all fields that used in query
   ///Above list changed to use temporary table
   List<Item> tmp_all_fields1, tmp_all_fields2, tmp_all_fields3;