MariaDB [test]> show create table tt\G

*************************** 1. row ***************************

       Table: tt

Create Table: CREATE TABLE `tt` (

  `a` int(11) DEFAULT NULL,

  `b` int(11) DEFAULT '1',

  KEY `b` (`b`)

) ENGINE=MyISAM DEFAULT CHARSET=latin1 PACK_KEYS=1 DELAY_KEY_WRITE=1

/*!50100 PARTITION BY HASH (b)

PARTITIONS 30 */

1 row in set (0.00 sec)

MariaDB [test]> alter online table tt delay_key_write=0;

Query OK, 0 rows affected (0.01 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> alter online table tt delay_key_write=1;

Query OK, 0 rows affected (0.00 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> create table ttt(id_1 int auto_increment, id_2 int, id_3 int, d1 date, dt1 datetime default current_timestamp, dt2 datetime default current_timestamp on update current_timestamp, primary key (id_2, id_3), key(id_1)) engine=myisam partition by hash(id_2) partitions 3 (partition p01 engine=myisam, partition p02 engine=myisam, partition p03 engine=myisam);

Query OK, 0 rows affected (0.04 sec)

MariaDB [test]> insert into ttt values(0, 1, 1, NULL, now(), now());

Query OK, 1 row affected (0.00 sec)

MariaDB [test]> select * from ttt;

+------+------+------+------+---------------------+---------------------+

| id_1 | id_2 | id_3 | d1   | dt1                 | dt2                 |

+------+------+------+------+---------------------+---------------------+

|    1 |    1 |    1 | NULL | 2017-06-15 10:35:10 | 2017-06-15 10:35:10 |

+------+------+------+------+---------------------+---------------------+

1 row in set (0.00 sec)

MariaDB [test]> alter online table tt delay_key_write=1;

Query OK, 0 rows affected (0.00 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> alter online table tt delay_key_write=0;

Query OK, 0 rows affected (0.01 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [test]> alter online table ttt delay_key_write=1;

ERROR 1845 (0A000): LOCK=NONE is not supported for this operation. Try LOCK=SHARED.

MariaDB [test]> alter online table ttt delay_key_write=1, lock=shared;

Query OK, 1 row affected (0.04 sec)

Records: 1  Duplicates: 0  Warnings: 0

MariaDB [test]> show create table ttt\G

*************************** 1. row ***************************

       Table: ttt

Create Table: CREATE TABLE `ttt` (

  `id_1` int(11) NOT NULL AUTO_INCREMENT,

  `id_2` int(11) NOT NULL,

  `id_3` int(11) NOT NULL,

  `d1` date DEFAULT NULL,

  `dt1` datetime DEFAULT CURRENT_TIMESTAMP,

  `dt2` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

  PRIMARY KEY (`id_2`,`id_3`),

  KEY `id_1` (`id_1`)

) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 DELAY_KEY_WRITE=1

/*!50100 PARTITION BY HASH (id_2)

(PARTITION p01 ENGINE = MyISAM,

 PARTITION p02 ENGINE = MyISAM,

 PARTITION p03 ENGINE = MyISAM) */

1 row in set (0.00 sec)