 MySQL.    c  (tmpdir)   .

https://drupal-admin.ru/blog/%D1%83%D1%81%D0%BA%D0%BE%D1%80%D1%8F%D0%B5%D0%BC-mysql-%D0%BF%D0%B5%D1%80%D0%B5%D0%BC%D0%B5%D1%89%D0%B5%D0%BD%D0%B8%D0%B5-%D0%B2%D1%80%D0%B5%D0%BC%D0%B5%D0%BD%D1%8B%D1%85-%D1%82%D0%B0%D0%B1%D0%BB%D0%B8%D1%86-c-%D0%B4%D0%B8%D1%81%D0%BA%D0%B0-tmpdir-%D0%B2-%D0%BE%D0%BF%D0%B5%D1%80%D0%B0%D1%82%D0%B8%D0%B2%D0%BD%D1%83%D1%8E-%D0%BF%D0%B0%D0%BC%D1%8F%D1%82%D1%8C

https://artkiev.com/blog/mysql-temp-table-in-ram.htm

 
https://habr.com/ru/post/539792/
