Re: manually create myisam table .myd .frm files

[Rick James]

Have your generating program generate and execute
INSERT INTO foo (a,b,c) VALUES
(1,2,3),
(11,22,33),
...
;
Do that in batches of 100 (the recommended number) rows per INSERT statement. This will come close to LOAD DATA speed. (Batches of 1000 won't be significantly faster; too big a batch will hit some limit.)

SHOW CREATE TABLE \G
What INDEXes do you have?

Sorting the data in PRIMARY KEY order will help speed up the INSERTs.

SHOW VARIABLES LIKE '%buffer%';
key_buffer_size should probably be 20% of available RAM.

DELAYED_KEY_WRITE may help.

Loading into a MyISAM table with _no_ indexes (not even PK), then ALTER TABLE to add the indexes may help.

Another approach...
1. CREATE TABLE foo (...) ENGINE=csv;
2. Generate the .csv file in the database directory.
3. ALTER TABLE foo
PRIMARY KEY (...),
INDEX ... ENGINE = MyISAM;
(Read about CSV files, make sure you have that Engine available, etc)
SHOW VARIABLES LIKE 'have%';