Drupal + "PHP Warning: MySQL server has gone away"

I recently had this error occur on one of my Drupal multi-site installations. If you're here, you're having this problem, too.

The likely problem

If your site isn't uber-high traffic and you're seeing this message, it's very likely related to the Update Status module.

The solution

Disable the Update Status module, especially if this is a multi-site installation. You may also increase the wait_timeout setting, if you have permission to do this on your host.

Why does this happen?

It seems the Update Status module makes as many HTTP requests as you have active modules every time cron is run. On a multisite installation, this could mean dozens and dozens of outbound HTTP requests to see what's new with your modules. The time this takes to process exceeds the wait_timeout count, and MySQL gets pissed.

How do I keep up with updates?

I'm keeping the Update Status module live on single-site setups that I have. You might consider creating a blank site with Update Status enabled, just so you can check up on it to see what's up.

Hope this has been helpful.