I started using this plugin last year; it does a pretty good job of hosing out the database when used on a regular basis.
Until, of course, it doesn’t. Judging by the changelog, it’s been a rough few days for the poor guy:
2.7.3 [12/09/2013]BUG FIX: deleted some CR/LF’s from the end of the plugin sigh
2.7.2 [12/09/2013]BUG FIX: forgot to delete a debug item… oops! sorry!
2.7.1 [12/09/2013]BUG FIX: query and depreciated item (mysql_list_tables) fixed
2.7 [12/06/2013]NEW: deletion of expired transients (optional)
I’d deactivated it for a while, figuring he’d straighten it out eventually. Looks like maybe he did.