troubleshooting mysqlimport very large text file
The problem with this starts with the my.cnf

The table is using the MyISAM Storage Engine but you have no MyISAM specific options in my.cnf

You are getting the "repair by keycache" because the MyISAM Key Cache is way too small. The default key_buffer_size in MySQL 5.7 is 8MB. Also note that you could have set up the MyISAM bulk insert buffer, whose default is also 8MB.

If you had added this to the my.cnf

[mysqld]
key_buffer_size = 1G (or 2G)
bulk_insert_buffer_size = 256M (or 512M)


and restarted mysqld, you could have bulk loaded without changing the data files all that much.