Merge mhansson@bk-internal:/home/bk/mysql-5.1-opt

into  linux-st28.site:/home/martin/mysql/src/5.1o-bug30596


sql/sql_select.cc:
  Auto merged

mysql-test/include/mix1.inc

@@ -969,6 +969,33 @@ ROLLBACK;
 ROLLBACK;
 DROP TABLE t1;
 
+#
+# Bug#30596: GROUP BY optimization gives wrong result order
+#  
+CREATE TABLE t1(
+  a INT, 
+  b INT NOT NULL, 
+  c INT NOT NULL, 
+  d INT, 
+  UNIQUE KEY (c,b)
+) engine=innodb;
+
+INSERT INTO t1 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4);
+
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d;
+SELECT c,b,d FROM t1 GROUP BY c,b,d;
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+EXPLAIN SELECT c,b,d FROM t1 ORDER BY c,b,d;
+SELECT c,b,d FROM t1 ORDER BY c,b,d;
+
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b;
+SELECT c,b,d FROM t1 GROUP BY c,b;
+EXPLAIN SELECT c,b   FROM t1 GROUP BY c,b;
+SELECT c,b   FROM t1 GROUP BY c,b;
+
+DROP TABLE t1;
+
 --echo End of 5.0 tests
 
 # Fix for BUG#19243 "wrong LAST_INSERT_ID() after ON DUPLICATE KEY

mysql-test/r/distinct.result

@@ -526,10 +526,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	3	Using index
 EXPLAIN SELECT a,b FROM t1 GROUP BY a,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
 EXPLAIN SELECT DISTINCT a,b FROM t1 GROUP BY a,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
 CREATE TABLE t2(a INT, b INT NOT NULL, c INT NOT NULL, d INT, 
 PRIMARY KEY (a,b));
 INSERT INTO t2 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4);
@@ -554,7 +554,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 CREATE UNIQUE INDEX c_b_unq ON t2 (c,b);
 EXPLAIN SELECT DISTINCT a,b,d FROM t2 GROUP BY c,b,d;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using filesort
 DROP TABLE t1,t2;
 create table t1 (id int, dsc varchar(50));
 insert into t1 values (1, "line number one"), (2, "line number two"), (3, "line number three");

mysql-test/r/group_by.result

@@ -1093,7 +1093,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	144	
 EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR GROUP BY (PRIMARY,i2) GROUP BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	144	Using index
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	144	Using index; Using filesort
 EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (PRIMARY,i2) ORDER BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	144	Using index; Using filesort
@@ -1176,3 +1176,94 @@ old	OFF
 SET @@old = off;
 ERROR HY000: Variable 'old' is a read only variable
 DROP TABLE t1, t2;
+CREATE TABLE t1(
+a INT, 
+b INT NOT NULL, 
+c INT NOT NULL, 
+d INT, 
+UNIQUE KEY (c,b)
+);
+INSERT INTO t1 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4);
+CREATE TABLE t2(
+a INT,
+b INT,
+UNIQUE KEY(a,b)
+);
+INSERT INTO t2 VALUES (NULL, NULL), (NULL, NULL), (NULL, 1), (1, NULL), (1, 1), (1,2);
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
+SELECT c,b,d FROM t1 GROUP BY c,b,d;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
+SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+c	b	d
+1	1	50
+3	2	40
+3	1	4
+EXPLAIN SELECT c,b,d FROM t1 ORDER BY c,b,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
+SELECT c,b,d FROM t1 ORDER BY c,b,d;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
+SELECT c,b,d FROM t1 GROUP BY c,b;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b   FROM t1 GROUP BY c,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	c	8	NULL	3	Using index
+SELECT c,b   FROM t1 GROUP BY c,b;
+c	b
+1	1
+3	1
+3	2
+EXPLAIN SELECT a,b from t2 ORDER BY a,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	a	10	NULL	6	Using index
+SELECT a,b from t2 ORDER BY a,b;
+a	b
+NULL	NULL
+NULL	NULL
+NULL	1
+1	NULL
+1	1
+1	2
+EXPLAIN SELECT a,b from t2 GROUP BY a,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	a	10	NULL	6	Using index
+SELECT a,b from t2 GROUP BY a,b;
+a	b
+NULL	NULL
+NULL	1
+1	NULL
+1	1
+1	2
+EXPLAIN SELECT a from t2 GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	a	10	NULL	6	Using index
+SELECT a from t2 GROUP BY a;
+a
+NULL
+1
+EXPLAIN SELECT b from t2 GROUP BY b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	a	10	NULL	6	Using index; Using temporary; Using filesort
+SELECT b from t2 GROUP BY b;
+b
+NULL
+1
+2
+DROP TABLE t1;

mysql-test/r/innodb_mysql.result

@@ -1141,6 +1141,55 @@ a	b
 ROLLBACK;
 ROLLBACK;
 DROP TABLE t1;
+CREATE TABLE t1(
+a INT, 
+b INT NOT NULL, 
+c INT NOT NULL, 
+d INT, 
+UNIQUE KEY (c,b)
+) engine=innodb;
+INSERT INTO t1 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4);
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
+SELECT c,b,d FROM t1 GROUP BY c,b,d;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
+SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b,d FROM t1 ORDER BY c,b,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using filesort
+SELECT c,b,d FROM t1 ORDER BY c,b,d;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	c	8	NULL	3	
+SELECT c,b,d FROM t1 GROUP BY c,b;
+c	b	d
+1	1	50
+3	1	4
+3	2	40
+EXPLAIN SELECT c,b   FROM t1 GROUP BY c,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	c	8	NULL	3	Using index
+SELECT c,b   FROM t1 GROUP BY c,b;
+c	b
+1	1
+3	1
+3	2
+DROP TABLE t1;
 End of 5.0 tests
 CREATE TABLE `t2` (
 `k` int(11) NOT NULL auto_increment,

mysql-test/t/group_by.test

@@ -861,3 +861,47 @@ SHOW VARIABLES LIKE 'old';
 SET @@old = off;  
 
 DROP TABLE t1, t2;
+
+#
+# Bug#30596: GROUP BY optimization gives wrong result order
+#
+CREATE TABLE t1(
+  a INT, 
+  b INT NOT NULL, 
+  c INT NOT NULL, 
+  d INT, 
+  UNIQUE KEY (c,b)
+);
+
+INSERT INTO t1 VALUES (1,1,1,50), (1,2,3,40), (2,1,3,4);
+
+CREATE TABLE t2(
+  a INT,
+  b INT,
+  UNIQUE KEY(a,b)
+);
+
+INSERT INTO t2 VALUES (NULL, NULL), (NULL, NULL), (NULL, 1), (1, NULL), (1, 1), (1,2);
+
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d;
+SELECT c,b,d FROM t1 GROUP BY c,b,d;
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+SELECT c,b,d FROM t1 GROUP BY c,b,d ORDER BY NULL;
+EXPLAIN SELECT c,b,d FROM t1 ORDER BY c,b,d;
+SELECT c,b,d FROM t1 ORDER BY c,b,d;
+
+EXPLAIN SELECT c,b,d FROM t1 GROUP BY c,b;
+SELECT c,b,d FROM t1 GROUP BY c,b;
+EXPLAIN SELECT c,b   FROM t1 GROUP BY c,b;
+SELECT c,b   FROM t1 GROUP BY c,b;
+
+EXPLAIN SELECT a,b from t2 ORDER BY a,b;
+SELECT a,b from t2 ORDER BY a,b;
+EXPLAIN SELECT a,b from t2 GROUP BY a,b;
+SELECT a,b from t2 GROUP BY a,b;
+EXPLAIN SELECT a from t2 GROUP BY a;
+SELECT a from t2 GROUP BY a;
+EXPLAIN SELECT b from t2 GROUP BY b;
+SELECT b from t2 GROUP BY b;
+
+DROP TABLE t1;

sql/sql_select.cc

@@ -1069,6 +1069,20 @@ JOIN::optimize()
                                  find_field_in_order_list,
                                  (void *) group_list))
     {
+      /*
+        We have found that grouping can be removed since groups correspond to
+        only one row anyway, but we still have to guarantee correct result
+        order. The line below effectively rewrites the query from GROUP BY
+        <fields> to ORDER BY <fields>. One exception is if skip_sort_order is
+        set (see above), then we can simply skip GROUP BY.
+      */
+      order= skip_sort_order ? 0 : group_list;
+      /*
+        If we have an IGNORE INDEX FOR GROUP BY(fields) clause, this must be 
+        rewritten to IGNORE INDEX FOR ORDER BY(fields).
+      */
+      join_tab->table->keys_in_use_for_order_by=
+        join_tab->table->keys_in_use_for_group_by;
       group_list= 0;
       group= 0;
     }