One of our customers was running into issues with the content-autolinks.php module in your plugin. It's currently causing the InnoDB buffer to inflate way past its limits. Once of our team members was looking into this as soon as the InnoDB engine started crashing and found this:
What's being run is in plugins/seo-ultimate/modules/autolinks/content-autolinks.php on line 211 – function update_max_post_dates().
For example, see line 244 where it queries the posts table and causes the content to be lowercased. This means it must load all of the text and never uses any index. Compare that to a standard LIKE expression, which is already case insensitive. Furthermore there's no limit on their current query so it will (and does) pull all posts into memory.
Then, from what I can tell, it appears to be re-writing all of that post data even if it doesn't need to be rewritten. That causes a ridiculous load and, in this case, makes the InnoDB buffer go over its limits.
I was going to attempt to disclose this information to you, but I could not find any public facing contact info for the developers. Still, I hope this helps you improve things on your end.