Since upgrading to 3.0.4, I've had sporadic issues. Now, I can't get the site to load at all - wp-admin, main page, nothing.
Server logs show wp_cache_init errors on each page load; e.g.,
2011/01/03 01:02:40 [error] 13253#0: *1757 FastCGI sent in stderr: "PHP Fatal error: Call to undefined function wp_cache_init() in /home/noise/wp-includes/load.php on line 378" while reading response header from upstream, client: 18.104.22.168, server: noisepages.com, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/dev/shm/php-fastcgi.sock:", host: "createdigitalmotion.com", referrer: "http://www.google.com/reader/view/"
I'm running nginx + APC.
I have tried disabling the MySQL query cache and APC caching temporarily to see if those were somehow conflicting (based on previous comments) -- nothing.
Also, I tried doing a clean install of WP in a separate directory and switching to that. That fixed everything -- for about fifteen minutes, and then the problem resurfaced (which *really* says to me there's a caching problem!)
I would think that disabling the WP cache would resolve the issue, right? Shouldn't I be able to choose --
-- in wp-config.php?