Large installation, comments timeout

White page is PHP, and at the comment page, I’d guess you just have a LOT of comments.

How many?

Have you run a repair on the DB? Emptied spam and trash comments?

Thx for the answer!

Since it’s a multisite, I don’t really know how many comments there are, as I said it’s about 24 000 blogs and most of them more or less active, so I would guess around 200 000 – 500 000 comments, at least.

The issue affects all blogs, not just the busy ones. Writing new posts works great, so i can’t see that there should be an issue with slow writing or similar to the database.

I enabled error reporting in PHP, but didn’t get any errors on that page, neither on screen nor in the error-log, (i did receive errors, so i know that the reporting works).

Are there any functions in the wp-comments-post.php that are known to make a fuss?

Do you have any third party comment plugins enabled, something could be timing out somewhere or limiting it at least?

Also look at enabling APC opcode caching if you haven’t already, that sped ours up a lot. Definitely do a repair/optimize on the entire DB when it’s quiet if you can.

Finally it would be good to check with something like the debugbar plugin to see what queries are being run, check slow queries log too in mysql.