Is there a way to change the tmpdir on a MySQL server without restarting it? The issue is that I use a tmpfs mounted at /var/lib/mysqltmp but sometimes it's overflowing and causes issues. I don't want to restart the server, because that means around 2-3 hours of service degradation.
Another possible exit from this situation is to unmount the tmpfs, but trying it causes this error:
[root@db2 /]# umount /var/lib/mysqltmp/
umount: /var/lib/mysqltmp: device is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))