Merge

include/my_base.h:
  Auto merged
include/my_global.h:
  Auto merged
include/my_sys.h:
  Auto merged
isam/test2.c:
  Auto merged
myisam/mi_check.c:
  Auto merged
myisam/mi_test2.c:
  Auto merged
myisam/myisamchk.c:
  Auto merged
myisam/myisamdef.h:
  Auto merged
mysql-test/r/func_group.result:
  Auto merged
sql/ha_myisam.cc:
  Auto merged
sql/handler.cc:
  Auto merged
sql/handler.h:
  Auto merged
sql/item_cmpfunc.h:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/opt_range.cc:
  Auto merged
sql/set_var.h:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_lex.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/sql_test.cc:
  Auto merged
sql/sql_yacc.yy:
  Auto merged
sql/mysqld.cc:
  SCCS merged
sql/set_var.cc:
  SCCS merged

5 files changed, 511 insertions, 28 deletions

diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result
index 8b7581c3cc8..2fb38ffe592 100644
--- a/mysql-test/r/func_group.result
+++ b/mysql-test/r/func_group.result
@@ -514,7 +514,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain 
 select min(a1) from t1 where a1 != 'KKK';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	NULL	PRIMARY	3	NULL	14	Using where; Using index
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	3	NULL	14	Using where; Using index
 explain
 select max(a3) from t1 where a2 < 2 and a3 < 'SEA';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -560,7 +560,7 @@ explain
 select concat(min(t1.a1),min(t2.a4)) from t1, t2 where t2.a4 <> 'AME';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	PRIMARY	3	NULL	14	Using index
-1	SIMPLE	t2	index	NULL	k2	4	NULL	6	Using where; Using index
+1	SIMPLE	t2	range	k2	k2	4	NULL	6	Using where; Using index
 drop table t1, t2;
 CREATE TABLE t1 (a int, b int);
 select count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1;
diff --git a/mysql-test/r/key_cache.result b/mysql-test/r/key_cache.result
index dd45cb51d33..79fe0599bc4 100644
--- a/mysql-test/r/key_cache.result
+++ b/mysql-test/r/key_cache.result
@@ -41,3 +41,194 @@ SELECT @@default.key_buffer_size;
 ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'default.key_buffer_size' at line 1
 SELECT @@skr.table_type="test";
 ERROR HY000: Variable 'table_type' is not a variable component (Can't be used as XXXX.variable_name)
+select @@keycache1.key_cache_block_size;
+@@keycache1.key_cache_block_size
+0
+select @@keycache1.key_buffer_size;
+@@keycache1.key_buffer_size
+0
+set global keycache1.key_cache_block_size=2048;
+select @@keycache1.key_buffer_size;
+@@keycache1.key_buffer_size
+0
+select @@keycache1.key_cache_block_size;
+@@keycache1.key_cache_block_size
+2048
+set global keycache1.key_buffer_size=1*1024*1024;
+select @@keycache1.key_buffer_size;
+@@keycache1.key_buffer_size
+1048576
+select @@keycache1.key_cache_block_size;
+@@keycache1.key_cache_block_size
+2048
+set global keycache2.key_buffer_size=4*1024*1024;
+select @@keycache2.key_buffer_size;
+@@keycache2.key_buffer_size
+4194304
+select @@keycache2.key_cache_block_size;
+@@keycache2.key_cache_block_size
+1024
+set global keycache1.key_buffer_size=0;
+select @@keycache1.key_buffer_size;
+@@keycache1.key_buffer_size
+0
+select @@keycache1.key_cache_block_size;
+@@keycache1.key_cache_block_size
+0
+select @@key_buffer_size;
+@@key_buffer_size
+2097152
+select @@key_cache_block_size;
+@@key_cache_block_size
+1024
+drop table if exists t1, t2;
+create table t1 (p int primary key, a char(10));
+create table t2 (p int primary key, i int, a char(10), key k1(i), key k2(a));
+insert into t1 values (1, 'qqqq'), (11, 'yyyy');
+insert into t2 values (1, 1, 'qqqq'), (2, 1, 'pppp'),
+(3, 1, 'yyyy'), (4, 3, 'zzzz');
+select * from t1;
+p	a
+1	qqqq
+11	yyyy
+select * from t2;
+p	i	a
+1	1	qqqq
+2	1	pppp
+3	1	yyyy
+4	3	zzzz
+update t1 set p=2 where p=1;
+update t2 set i=2 where i=1;
+cache index t1 keys in keycache1;
+Table	Op	Msg_type	Msg_text
+test.t1	assign_to_keycache	status	OK
+explain select p from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	2	Using index
+select p from t1;
+p
+2
+11
+explain select i from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	k1	5	NULL	4	Using index
+select i from t2;
+i
+2
+2
+2
+3
+explain select count(*) from t1, t2 where t1.p = t2.i;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	2	Using index
+1	SIMPLE	t2	ref	k1	k1	5	test.t1.p	2	Using where; Using index
+select count(*) from t1, t2 where t1.p = t2.i;
+count(*)
+3
+cache index t2 keys in keycache1;
+Table	Op	Msg_type	Msg_text
+test.t2	assign_to_keycache	status	OK
+update t2 set p=p+1000, i=2 where a='qqqq';
+cache index t2 keys in keycache2;
+Table	Op	Msg_type	Msg_text
+test.t2	assign_to_keycache	status	OK
+insert into t2 values (2000, 3, 'yyyy');
+cache index t2 keys in keycache1;
+Table	Op	Msg_type	Msg_text
+test.t2	assign_to_keycache	status	OK
+update t2 set p=3000 where a='zzzz';
+select * from t2;
+p	i	a
+1001	2	qqqq
+2	2	pppp
+3	2	yyyy
+3000	3	zzzz
+2000	3	yyyy
+explain select p from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	PRIMARY	4	NULL	5	Using index
+select p from t2;
+p
+2
+3
+1001
+2000
+3000
+explain select i from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	k1	5	NULL	5	Using index
+select i from t2;
+i
+2
+2
+2
+3
+3
+explain select a from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	k2	11	NULL	5	Using index
+select a from t2;
+a
+pppp
+qqqq
+yyyy
+yyyy
+zzzz
+select @@keycache2.key_buffer_size;
+@@keycache2.key_buffer_size
+4194304
+select @@keycache2.key_cache_block_size;
+@@keycache2.key_cache_block_size
+1024
+set global keycache2.key_buffer_size=0;
+select @@keycache2.key_buffer_size;
+@@keycache2.key_buffer_size
+0
+select @@keycache2.key_cache_block_size;
+@@keycache2.key_cache_block_size
+0
+update t2 set p=4000 where a='zzzz';
+update t1 set p=p+1;
+set global keycache1.key_buffer_size=0;
+select * from t2;
+p	i	a
+1001	2	qqqq
+2	2	pppp
+3	2	yyyy
+4000	3	zzzz
+2000	3	yyyy
+select p from t2;
+p
+2
+3
+1001
+2000
+4000
+explain select i from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	k1	5	NULL	5	Using index
+select i from t2;
+i
+2
+2
+2
+3
+3
+explain select a from t2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	k2	11	NULL	5	Using index
+select a from t2;
+a
+pppp
+qqqq
+yyyy
+yyyy
+zzzz
+select * from t1;
+p	a
+3	qqqq
+12	yyyy
+select p from t1;
+p
+3
+12
diff --git a/mysql-test/r/range.result b/mysql-test/r/range.result
index 9f76676ee1a..db477fc662f 100644
--- a/mysql-test/r/range.result
+++ b/mysql-test/r/range.result
@@ -1,4 +1,4 @@
-drop table if exists t1;
+drop table if exists t1, t2;
 CREATE TABLE t1 (
 event_date date DEFAULT '0000-00-00' NOT NULL,
 type int(11) DEFAULT '0' NOT NULL,
@@ -215,17 +215,6 @@ select count(*) from t1 where art = 'J';
 count(*)
 213
 drop table t1;
-create table t1 ( id1 int not null, id2 int not null, idnull int null, c char(20), primary key (id1,id2));
-insert into t1 values (0,1,NULL,"aaa"), (1,1,NULL,"aaa"), (2,1,NULL,"aaa"),
-(3,1,NULL,"aaa"), (4,1,NULL,"aaa"), (5,1,NULL,"aaa"),
-(6,1,NULL,"aaa"), (7,1,NULL,"aaa"), (8,1,NULL,"aaa"),
-(9,1,NULL,"aaa"), (10,1,NULL,"aaa"), (11,1,NULL,"aaa"),
-(12,1,NULL,"aaa"), (13,1,NULL,"aaa"), (14,1,NULL,"aaa"),
-(15,1,NULL,"aaa"), (16,1,NULL,"aaa"), (17,1,NULL,"aaa"),
-(18,1,NULL,"aaa"), (19,1,NULL,"aaa"), (20,1,NULL,"aaa");
-select a.id1, b.idnull from t1 as a, t1 as b where a.id2=1 and a.id1=1 and b.id1=a.idnull order by b.id2 desc limit 1;
-id1	idnull
-drop table t1;
 create table t1 (x int, y int, index(x), index(y));
 insert into t1 (x) values (1),(2),(3),(4),(5),(6),(7),(8),(9);
 update t1 set y=x;
@@ -286,3 +275,145 @@ id
 5
 9
 drop table t1;
+create table t1 ( id1 int not null, id2 int not null, idnull int null, c char(20), primary key (id1,id2));
+insert into t1 values (0,1,NULL,"aaa"), (1,1,NULL,"aaa"), (2,1,NULL,"aaa"),
+(3,1,NULL,"aaa"), (4,1,NULL,"aaa"), (5,1,NULL,"aaa"),
+(6,1,NULL,"aaa"), (7,1,NULL,"aaa"), (8,1,NULL,"aaa"),
+(9,1,NULL,"aaa"), (10,1,NULL,"aaa"), (11,1,NULL,"aaa"),
+(12,1,NULL,"aaa"), (13,1,NULL,"aaa"), (14,1,NULL,"aaa"),
+(15,1,NULL,"aaa"), (16,1,NULL,"aaa"), (17,1,NULL,"aaa"),
+(18,1,NULL,"aaa"), (19,1,NULL,"aaa"), (20,1,NULL,"aaa");
+select a.id1, b.idnull from t1 as a, t1 as b where a.id2=1 and a.id1=1 and b.id1=a.idnull order by b.id2 desc limit 1;
+id1	idnull
+drop table t1;
+create table t1 (
+id int not null auto_increment,
+name char(1) not null,
+uid int not null,
+primary key (id),
+index uid_index (uid));
+create table t2 (
+id int not null auto_increment,
+name char(1) not null,
+uid int not null,
+primary key (id),
+index uid_index (uid));
+insert into t1(id, uid, name) values(1, 0, ' ');
+insert into t1(uid, name) values(0, ' ');
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+delete from t2;
+insert into t2(uid, name) values 
+(1, CHAR(64+1)),
+(2, CHAR(64+2)),
+(3, CHAR(64+3)),
+(4, CHAR(64+4)),
+(5, CHAR(64+5)),
+(6, CHAR(64+6)),
+(7, CHAR(64+7)),
+(8, CHAR(64+8)),
+(9, CHAR(64+9)),
+(10, CHAR(64+10)),
+(11, CHAR(64+11)),
+(12, CHAR(64+12)),
+(13, CHAR(64+13)),
+(14, CHAR(64+14)),
+(15, CHAR(64+15)),
+(16, CHAR(64+16)),
+(17, CHAR(64+17)),
+(18, CHAR(64+18)),
+(19, CHAR(64+19)),
+(20, CHAR(64+20)),
+(21, CHAR(64+21)),
+(22, CHAR(64+22)),
+(23, CHAR(64+23)),
+(24, CHAR(64+24)),
+(25, CHAR(64+25)),
+(26, CHAR(64+26));
+insert into t1(uid, name) select uid, name from t2;
+delete from t2;
+insert into t2(id, uid, name) select id, uid, name from t1;
+select count(*) from t1;
+count(*)
+1026
+select count(*) from t2;
+count(*)
+1026
+explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	128	Using where
+1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
+explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid != 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	129	Using where
+1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
+select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
+id	name	uid	id	name	uid
+1001	A	1	1001	A	1
+1002	B	2	1002	B	2
+1003	C	3	1003	C	3
+1004	D	4	1004	D	4
+1005	E	5	1005	E	5
+1006	F	6	1006	F	6
+1007	G	7	1007	G	7
+1008	H	8	1008	H	8
+1009	I	9	1009	I	9
+1010	J	10	1010	J	10
+1011	K	11	1011	K	11
+1012	L	12	1012	L	12
+1013	M	13	1013	M	13
+1014	N	14	1014	N	14
+1015	O	15	1015	O	15
+1016	P	16	1016	P	16
+1017	Q	17	1017	Q	17
+1018	R	18	1018	R	18
+1019	S	19	1019	S	19
+1020	T	20	1020	T	20
+1021	U	21	1021	U	21
+1022	V	22	1022	V	22
+1023	W	23	1023	W	23
+1024	X	24	1024	X	24
+1025	Y	25	1025	Y	25
+1026	Z	26	1026	Z	26
+select * from t1, t2  where t1.uid=t2.uid AND t1.uid != 0;
+id	name	uid	id	name	uid
+1001	A	1	1001	A	1
+1002	B	2	1002	B	2
+1003	C	3	1003	C	3
+1004	D	4	1004	D	4
+1005	E	5	1005	E	5
+1006	F	6	1006	F	6
+1007	G	7	1007	G	7
+1008	H	8	1008	H	8
+1009	I	9	1009	I	9
+1010	J	10	1010	J	10
+1011	K	11	1011	K	11
+1012	L	12	1012	L	12
+1013	M	13	1013	M	13
+1014	N	14	1014	N	14
+1015	O	15	1015	O	15
+1016	P	16	1016	P	16
+1017	Q	17	1017	Q	17
+1018	R	18	1018	R	18
+1019	S	19	1019	S	19
+1020	T	20	1020	T	20
+1021	U	21	1021	U	21
+1022	V	22	1022	V	22
+1023	W	23	1023	W	23
+1024	X	24	1024	X	24
+1025	Y	25	1025	Y	25
+1026	Z	26	1026	Z	26
+drop table t1,t2;
diff --git a/mysql-test/t/key_cache.test b/mysql-test/t/key_cache.test
index fb6b6b0027f..371d610eb5f 100644
--- a/mysql-test/t/key_cache.test
+++ b/mysql-test/t/key_cache.test
@@ -1,5 +1,5 @@
 #
-# Test of key cache
+# Test of multiple key caches
 #
 
 SET @save_key_buffer=@@key_buffer_size;
@@ -40,3 +40,83 @@ SET @@global.key_buffer_size=@save_key_buffer;
 SELECT @@default.key_buffer_size;
 --error 1271
 SELECT @@skr.table_type="test";
+
+select @@keycache1.key_cache_block_size;
+select @@keycache1.key_buffer_size;
+set global keycache1.key_cache_block_size=2048;
+select @@keycache1.key_buffer_size;
+select @@keycache1.key_cache_block_size;
+set global keycache1.key_buffer_size=1*1024*1024;
+select @@keycache1.key_buffer_size;
+select @@keycache1.key_cache_block_size;
+set global keycache2.key_buffer_size=4*1024*1024;
+select @@keycache2.key_buffer_size;
+select @@keycache2.key_cache_block_size;
+set global keycache1.key_buffer_size=0;
+select @@keycache1.key_buffer_size;
+select @@keycache1.key_cache_block_size;
+select @@key_buffer_size;
+select @@key_cache_block_size;
+
+
+--disable_warnings
+drop table if exists t1, t2;
+--enable_warnings
+
+create table t1 (p int primary key, a char(10));
+create table t2 (p int primary key, i int, a char(10), key k1(i), key k2(a));
+
+insert into t1 values (1, 'qqqq'), (11, 'yyyy');
+insert into t2 values (1, 1, 'qqqq'), (2, 1, 'pppp'),
+                      (3, 1, 'yyyy'), (4, 3, 'zzzz');
+select * from t1;
+select * from t2;
+
+update t1 set p=2 where p=1;
+update t2 set i=2 where i=1;
+
+cache index t1 keys in keycache1;
+
+explain select p from t1;
+select p from t1;
+explain select i from t2;
+select i from t2;
+explain select count(*) from t1, t2 where t1.p = t2.i;
+select count(*) from t1, t2 where t1.p = t2.i;
+
+cache index t2 keys in keycache1;
+update t2 set p=p+1000, i=2 where a='qqqq';
+cache index t2 keys in keycache2;
+insert into t2 values (2000, 3, 'yyyy');
+cache index t2 keys in keycache1;
+update t2 set p=3000 where a='zzzz';
+select * from t2;
+explain select p from t2;
+select p from t2;
+explain select i from t2;
+select i from t2;
+explain select a from t2;
+select a from t2;
+
+select @@keycache2.key_buffer_size;
+select @@keycache2.key_cache_block_size;
+set global keycache2.key_buffer_size=0;
+select @@keycache2.key_buffer_size;
+select @@keycache2.key_cache_block_size;
+
+
+update t2 set p=4000 where a='zzzz';
+update t1 set p=p+1;
+
+set global keycache1.key_buffer_size=0;
+select * from t2;
+select p from t2;
+explain select i from t2;
+select i from t2;
+explain select a from t2;
+select a from t2;
+
+select * from t1;
+select p from t1;
+
+
diff --git a/mysql-test/t/range.test b/mysql-test/t/range.test
index 7bf6570b558..40ae49f8005 100644
--- a/mysql-test/t/range.test
+++ b/mysql-test/t/range.test
@@ -3,7 +3,7 @@
 #
 
 --disable_warnings
-drop table if exists t1;
+drop table if exists t1, t2;
 --enable_warnings
 
 CREATE TABLE t1 (
@@ -174,18 +174,6 @@ select count(*) from t1 where art = 'j' or art = 'J';
 select count(*) from t1 where art = 'j';
 select count(*) from t1 where art = 'J';
 drop table t1;
-
-create table t1 ( id1 int not null, id2 int not null, idnull int null, c char(20), primary key (id1,id2));
-insert into t1 values (0,1,NULL,"aaa"), (1,1,NULL,"aaa"), (2,1,NULL,"aaa"),
-                      (3,1,NULL,"aaa"), (4,1,NULL,"aaa"), (5,1,NULL,"aaa"),
-                      (6,1,NULL,"aaa"), (7,1,NULL,"aaa"), (8,1,NULL,"aaa"),
-                      (9,1,NULL,"aaa"), (10,1,NULL,"aaa"), (11,1,NULL,"aaa"),
-                      (12,1,NULL,"aaa"), (13,1,NULL,"aaa"), (14,1,NULL,"aaa"),
-                      (15,1,NULL,"aaa"), (16,1,NULL,"aaa"), (17,1,NULL,"aaa"),
-                      (18,1,NULL,"aaa"), (19,1,NULL,"aaa"), (20,1,NULL,"aaa");
-select a.id1, b.idnull from t1 as a, t1 as b where a.id2=1 and a.id1=1 and b.id1=a.idnull order by b.id2 desc limit 1;
-drop table t1;
-
 #
 # BETWEEN problems
 #
@@ -225,3 +213,96 @@ insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9);
 select id from t1 where id in (2,5,9) ;
 select id from t1 where id=2 or id=5 or id=9 ;
 drop table t1;
+create table t1 ( id1 int not null, id2 int not null, idnull int null, c char(20), primary key (id1,id2));
+insert into t1 values (0,1,NULL,"aaa"), (1,1,NULL,"aaa"), (2,1,NULL,"aaa"),
+                      (3,1,NULL,"aaa"), (4,1,NULL,"aaa"), (5,1,NULL,"aaa"),
+                      (6,1,NULL,"aaa"), (7,1,NULL,"aaa"), (8,1,NULL,"aaa"),
+                      (9,1,NULL,"aaa"), (10,1,NULL,"aaa"), (11,1,NULL,"aaa"),
+                      (12,1,NULL,"aaa"), (13,1,NULL,"aaa"), (14,1,NULL,"aaa"),
+                      (15,1,NULL,"aaa"), (16,1,NULL,"aaa"), (17,1,NULL,"aaa"),
+                      (18,1,NULL,"aaa"), (19,1,NULL,"aaa"), (20,1,NULL,"aaa");
+select a.id1, b.idnull from t1 as a, t1 as b where a.id2=1 and a.id1=1 and b.id1=a.idnull order by b.id2 desc limit 1;
+drop table t1;
+
+
+#
+# Problem with optimizing !=
+#
+
+create table t1 (
+  id int not null auto_increment,
+  name char(1) not null,
+  uid int not null,
+  primary key (id),
+  index uid_index (uid));
+  
+create table t2 (
+  id int not null auto_increment,
+  name char(1) not null,
+  uid int not null,
+  primary key (id),
+  index uid_index (uid));
+  
+insert into t1(id, uid, name) values(1, 0, ' ');
+insert into t1(uid, name) values(0, ' ');
+
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t2(uid, name) select uid, name from t1;
+insert into t1(uid, name) select uid, name from t2;
+
+delete from t2;
+insert into t2(uid, name) values 
+  (1, CHAR(64+1)),
+  (2, CHAR(64+2)),
+  (3, CHAR(64+3)),
+  (4, CHAR(64+4)),
+  (5, CHAR(64+5)),
+  (6, CHAR(64+6)),
+  (7, CHAR(64+7)),
+  (8, CHAR(64+8)),
+  (9, CHAR(64+9)),
+  (10, CHAR(64+10)),
+  (11, CHAR(64+11)),
+  (12, CHAR(64+12)),
+  (13, CHAR(64+13)),
+  (14, CHAR(64+14)),
+  (15, CHAR(64+15)),
+  (16, CHAR(64+16)),
+  (17, CHAR(64+17)),
+  (18, CHAR(64+18)),
+  (19, CHAR(64+19)),
+  (20, CHAR(64+20)),
+  (21, CHAR(64+21)),
+  (22, CHAR(64+22)),
+  (23, CHAR(64+23)),
+  (24, CHAR(64+24)),
+  (25, CHAR(64+25)),
+  (26, CHAR(64+26));
+
+insert into t1(uid, name) select uid, name from t2;
+
+delete from t2;
+insert into t2(id, uid, name) select id, uid, name from t1;
+
+select count(*) from t1;  
+select count(*) from t2;
+
+explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
+explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid != 0;
+
+select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
+select * from t1, t2  where t1.uid=t2.uid AND t1.uid != 0;
+
+drop table t1,t2;