Could this be due to exim? I am also seeing some abnormal volume of receive message in the “advance details” tab for email. Does this mean I have received 3,509 emails in the last 24 hours? I’e checked all my email inbox but less than 6 emails have been received.
Check /var/log/exim4/mainlog to see what is happening really.
Maybe an existing email account has been hacked (credentials stolen) and hackers are sending emails from it to external places. Or maybe any existent software or service is causing it for some reason (hacked or missconfigured).
Exim doesn’t use mysql so it is probally the mysql load…