I am experiencing some really strange behaviors with a large Drupal 7.8 site (185K nodes) and I'm pulling my hair out at this point.
For some reason, whenever I save stuff from the admin panel (especially views), the site grinds to a halt, and the page I submitted times out completely (usually resulting in a WSOD or partially rendered/unstyled page). The site becomes unusable until I clear the cache, and the CPU starts spinning.
When I clear the cache, everything works fine. Now ... get this:
When I use drush to clear the cache, I have to run it, and quickly stop it then start it again for it work. lol. I get a stream of these error messages if I don't.
$ ../drush/drush cc all
WD filter: Missing text format: 1. [error]
WD filter: Missing text format: 1. [error]
WD filter: Missing text format: 1. [error]
WD filter: Missing text format: 1. [error]