My wordpressblog produces http 500s on a small percentage of the requests. It doesn't seem to be tight to special urls, but it seems to happen clustered in time. i.e there are times when it happens more often for an hour or so, and then it stops happening for a couple of days.
I no probably nobody can tell me what is wrong with this description, but can anybody give me some tips how to debug this problem?
For example is there any way to extract some logging from wordpress? So far I only have the access log which comes from the apache running wordpress. And it only shows the http 500 no hint towards the reason for them.
Do you have WP-Cache installed or some other caching plugin? I've seen WP-Cache throw 500 errors from time to time in the past, though since switching to WP-Super-Cache, they've gone away.
It may also be a problem with the web-server. On my setup of lighttpd with only two fastcgi instances serving the requests, I do sometimes get 500 errors that go away when I increase it to three fastcgi instances.