ALTER TABLE ... DELAY_KEY_WRITE=1 creates table copy for partitioned MyISAM table with DATA DIRECTORY/INDEX DIRECTORY options

MariaDB [test]> create table tmi_part_dd ( c1 int, c2 int, c3 varchar(100)) engine=MyISAM delay_key_write=1 partition by key(c1) (partition p01 data directory = '/tmp' index directory = '/tmp' engine = MyISAM, partition p02 data directory = '/tmp' index directory = '/tmp' engine=MyISAM);

Query OK, 0 rows affected (0.07 sec)

MariaDB [test]> insert into tmi_part_dd values (1, 1, repeat('a', 100));

Query OK, 1 row affected (0.03 sec)

MariaDB [test]> insert into tmi_part_dd select rand()*1000, rand()*1000, repeat('b', 100) from tmi_part_dd;

Query OK, 1 row affected (0.01 sec)

Records: 1  Duplicates: 0  Warnings: 0

MariaDB [test]> insert into tmi_part_dd select rand()*1000, rand()*1000, repeat('b', 100) from tmi_part_dd;

Query OK, 2 rows affected (0.00 sec)

Records: 2  Duplicates: 0  Warnings: 0

MariaDB [test]> insert into tmi_part_dd select rand()*1000, rand()*1000, repeat('b', 100) from tmi_part_dd;

Query OK, 4 rows affected (0.00 sec)

Records: 4  Duplicates: 0  Warnings: 0

...

MariaDB [test]> alter table tmi_part_dd delay_key_write=0;

Stage: 2 of 2 'enabling keys'      0% of stage done

Query OK, 2097152 rows affected (3.24 sec)

Records: 2097152  Duplicates: 0  Warnings: 0

MariaDB [test]> alter table tmi_part_dd delay_key_write=1;

Query OK, 2097152 rows affected (1.94 sec)

Records: 2097152  Duplicates: 0  Warnings: 0

MariaDB [test]> select version();

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

| version()      |

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

| 10.2.9-MariaDB |

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

1 row in set (0.00 sec)

MariaDB [test]> \! ls /tmp/*.M*

/tmp/tmi_part_dd#P#p01.MYD  /tmp/tmi_part_dd#P#p02.MYD

/tmp/tmi_part_dd#P#p01.MYI  /tmp/tmi_part_dd#P#p02.MYI