create table t1 (a float not null, primary key(a)) engine='InnoDB' 
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` float NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY KEY (a)
(PARTITION pa1 MAX_ROWS = 20 MIN_ROWS = 2 ENGINE = InnoDB,
 PARTITION pa2 MAX_ROWS = 30 MIN_ROWS = 3 ENGINE = InnoDB,
 PARTITION pa3 MAX_ROWS = 30 MIN_ROWS = 4 ENGINE = InnoDB,
 PARTITION pa4 MAX_ROWS = 40 MIN_ROWS = 2 ENGINE = InnoDB) */
insert into t1 values (-3.402823466E+38), (3.402823466E+38), (-1.5), (-1), (0), (1), (1.5);
select * from t1;
a
0
-3.40282e+38
-1.5
-1
1
1.5
3.40282e+38
select * from t1 where a=1.5;
a
1.5
delete from t1 where a=1.5;
select * from t1;
a
0
-3.40282e+38
-1.5
-1
1
3.40282e+38
drop table t1;
create table t2 (a float not null, primary key(a)) engine='InnoDB' 
partition by key (a) partitions 10;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` float NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY KEY (a)
PARTITIONS 10 */
insert into t2 values (-3.402823466E+38), (-3.402823466E+37), (-123.456), (0), (1234546.789), (123.456), (1.5);
select * from t2;
a
0
1.5
-3.40282e+38
-123.456
-3.40282e+37
123.456
1.23455e+06
select * from t2 where a=123.456;
a
delete from t2 where a=123.456;
select * from t2;
a
0
1.5
-3.40282e+38
-123.456
-3.40282e+37
123.456
1.23455e+06
select * from t2 where a=1.5;
a
1.5
delete from t2 where a=1.5;
select * from t2;
a
0
-3.40282e+38
-123.456
-3.40282e+37
123.456
1.23455e+06
delete from t2;
1024*3 inserts;
select count(*) from t2;
count(*)
3072
drop table t2;
create table t1 (a double not null, primary key(a)) engine='InnoDB' 
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` double NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY KEY (a)
(PARTITION pa1 MAX_ROWS = 20 MIN_ROWS = 2 ENGINE = InnoDB,
 PARTITION pa2 MAX_ROWS = 30 MIN_ROWS = 3 ENGINE = InnoDB,
 PARTITION pa3 MAX_ROWS = 30 MIN_ROWS = 4 ENGINE = InnoDB,
 PARTITION pa4 MAX_ROWS = 40 MIN_ROWS = 2 ENGINE = InnoDB) */
insert into t1 values (-2.2250738585072014E+208), (-2.2250738585072014E-208), (-1.5), (-1), (0), (1.5), (1234.567), (2.2250738585072014E+208);
select * from t1;
a
1234.567
-2.2250738585072e-208
0
-2.2250738585072e+208
-1.5
-1
1.5
2.2250738585072e+208
select * from t1 where a=1.5;
a
1.5
delete from t1 where a=1.5;
select * from t1;
a
1234.567
-2.2250738585072e-208
0
-2.2250738585072e+208
-1.5
-1
2.2250738585072e+208
drop table t1;
create table t2 (a double not null, primary key(a)) engine='InnoDB' 
partition by key (a) partitions 10;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` double NOT NULL,
  PRIMARY KEY (`a`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY KEY (a)
PARTITIONS 10 */
insert into t2 values (-2.2250738585072014E+208), (-2.2250738585072014E-208), (-1.5), (-1), (0), (1.5), (1234.567), (2.2250738585072014E+208);
select * from t2;
a
-2.2250738585072e-208
0
2.2250738585072e+208
-2.2250738585072e+208
-1
1234.567
1.5
-1.5
select * from t2 where a=1234.567;
a
1234.567
delete from t2 where a=1234.567;
select * from t2;
a
-2.2250738585072e-208
0
2.2250738585072e+208
-2.2250738585072e+208
-1
1.5
-1.5
delete from t2;
1024*3 inserts;
select count(*) from t2;
count(*)
3072
drop table t2;