branches/5.1:

Merge change from MySQL (this almost fixes the failing innodb test):

  ChangeSet@1.2613, 2008-05-07 09:58:21+04:00, sergefp@mysql.com +5 -0
    BUG#35850 "Performance regression in 5.1.23/5.1.24"
    - Disable the "prefer full scan on clustered primary key over full scan
      of any secondary key" rule introduced by BUG#35850.
    - Update test results accordingly
    (bk trigger: file this for BUG#35850)
  
    mysql-test/r/innodb.result@1.214, 2008-05-07 09:57:31+04:00, sergefp@mysql.com +15 -15
      BUG#35850 "Performance regression in 5.1.23/5.1.24"
      - Update test results

mysql-test/innodb.result

@@ -925,7 +925,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	b	4	NULL	#	Using index
 explain select a,b from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	#	
+1	SIMPLE	t1	index	NULL	b	4	NULL	#	Using index
 explain select a,b,c from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#	
@@ -1166,14 +1166,14 @@ UPDATE t1 set a=a+100 where b between 2 and 3 and a < 1000;
 SELECT * from t1;
 a	b
 1	1
+102	2
+103	3
 4	4
 5	5
 6	6
 7	7
 8	8
 9	9
-102	2
-103	3
 drop table t1;
 CREATE TABLE t1 (a int not null primary key, b int not null, key (b)) engine=innodb;
 CREATE TABLE t2 (a int not null primary key, b int not null, key (b)) engine=innodb;
@@ -1197,6 +1197,7 @@ a	b
 update t1,t2 set t1.a=t1.a+100 where t1.a=101;
 select * from t1;
 a	b
+201	1
 102	2
 103	3
 104	4
@@ -1208,11 +1209,10 @@ a	b
 110	10
 111	11
 112	12
-201	1
 update t1,t2 set t1.b=t1.b+10 where t1.b=2;
 select * from t1;
 a	b
-102	12
+201	1
 103	3
 104	4
 105	5
@@ -1222,34 +1222,34 @@ a	b
 109	9
 110	10
 111	11
+102	12
 112	12
-201	1
 update t1,t2 set t1.b=t1.b+2,t2.b=t1.b+10 where t1.b between 3 and 5 and t1.a=t2.a+100;
 select * from t1;
 a	b
-102	12
+201	1
 103	5
 104	6
-105	7
 106	6
+105	7
 107	7
 108	8
 109	9
 110	10
 111	11
+102	12
 112	12
-201	1
 select * from t2;
 a	b
 1	1
 2	2
-3	13
-4	14
-5	15
 6	6
 7	7
 8	8
 9	9
+3	13
+4	14
+5	15
 drop table t1,t2;
 CREATE TABLE t2 (   NEXT_T         BIGINT NOT NULL PRIMARY KEY) ENGINE=MyISAM;
 CREATE TABLE t1 (  B_ID           INTEGER NOT NULL PRIMARY KEY) ENGINE=InnoDB;
@@ -1300,11 +1300,11 @@ insert into t1 (id) values (null),(null),(null),(null),(null);
 update t1 set fk=69 where fk is null order by id limit 1;
 SELECT * from t1;
 id	fk
-1	69
 2	NULL
 3	NULL
 4	NULL
 5	NULL
+1	69
 drop table t1;
 create table t1 (a int not null, b int not null, key (a));
 insert into t1 values (1,1),(1,2),(1,3),(3,1),(3,2),(3,3),(3,1),(3,2),(3,3),(2,1),(2,2),(2,3);
@@ -2438,8 +2438,8 @@ insert into t1 (b) values (1);
 replace into t1 (b) values (2), (1), (3);
 select * from t1;
 a	b
-2	2
 3	1
+2	2
 4	3
 truncate table t1;
 insert into t1 (b) values (1);
@@ -2448,8 +2448,8 @@ replace into t1 (b) values (1);
 replace into t1 (b) values (3);
 select * from t1;
 a	b
-2	2
 3	1
+2	2
 4	3
 drop table t1;
 create table t1 (rowid int not null auto_increment, val int not null,primary