create table t1 (a mediumint unsigned not null, primary key(a)) engine='MYISAM' 
partition by key (a) (
partition pa1 max_rows=20 min_rows=2,
partition pa2 max_rows=30 min_rows=3,
partition pa3 max_rows=30 min_rows=4,
partition pa4 max_rows=40 min_rows=2);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` mediumint(8) unsigned NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
 PARTITION BY KEY (`a`)
(PARTITION `pa1` MAX_ROWS = 20 MIN_ROWS = 2 ENGINE = MyISAM,
 PARTITION `pa2` MAX_ROWS = 30 MIN_ROWS = 3 ENGINE = MyISAM,
 PARTITION `pa3` MAX_ROWS = 30 MIN_ROWS = 4 ENGINE = MyISAM,
 PARTITION `pa4` MAX_ROWS = 40 MIN_ROWS = 2 ENGINE = MyISAM)
insert into t1 values (16777215), (16777214), (16777213), (16777212), (1), (2), (65535);
select * from t1;
a
1
16777212
16777213
16777214
16777215
2
65535
select * from t1 where a=16777213;
a
16777213
delete from t1 where a=16777213;
select * from t1;
a
1
16777212
16777214
16777215
2
65535
drop table t1;
create table t2 (a mediumint unsigned not null, primary key(a)) engine='MYISAM' 
partition by key (a) partitions 8;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` mediumint(8) unsigned NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
 PARTITION BY KEY (`a`)
PARTITIONS 8
insert into t2 values (16777215), (16777214), (16777213), (16777212);
select * from t2;
a
16777212
16777213
16777214
16777215
select * from t2 where a=16777213;
a
16777213
delete from t2 where a=16777213;
select * from t2;
a
16777212
16777214
16777215
delete from t2;
65535 inserts;
select count(*) from t2;
count(*)
65535
drop table t2;
create table t3 (a mediumint not null, primary key(a)) engine='MYISAM' 
partition by key (a) partitions 7;
show create table t3;
Table	Create Table
t3	CREATE TABLE `t3` (
  `a` mediumint(9) NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
 PARTITION BY KEY (`a`)
PARTITIONS 7
insert into t3 values (8388607), (8388606), (8388605), (8388604), (-8388608), (-8388607), (1), (-1), (0);
select * from t3;
a
-1
-8388607
-8388608
0
1
8388604
8388605
8388606
8388607
select * from t3 where a=8388605;
a
8388605
delete from t3 where a=8388605;
select * from t3;
a
-1
-8388607
-8388608
0
1
8388604
8388606
8388607
drop table t3;