I have a heavily modded phpBB 2.0.3 running at a webhost who is using FreeBSD out of AboveNet
I first set up phpBB 2.0.1 here last August. We did not encounter the problem described below until 5 days ago. I suspected it was the problem outlined inthe Session Table Fix tutorial and implemented it. It hasn't helped.
In the past two months, I've added the Shop and Bank mods and they've been popular. Ours is specialized community (English Speaking people in Taiwan) but it is growing -- so the added attention (volume) should also play a role.
Here is the latest message from my webhost, 2 days after I implemented the Sessions Table Fix.
we had to turn off your scripts in [your forum] directory again
there was 100 mysql connections from your script, and the system load was at 93! (normally its 1 or less)
The problem doesnt appear to be solved.
Here is what I can recommend as a fix
1) dont run that software anymore
2) place at the top of the scripts a file locking mechanism to lock one of 5 lockfiles. If it succeeds - continue processing, and unlock after completion. If it fails then send back a page saying "system too busy - try again later". This forces your scripts to run AT MOST 5 copies.
2b) you may also want to limit the number of connections per IP address to keep one user from hogging all your resources. A scan of the outstanding requests on your site showed most of your connections was coming from a single IP address.
solution 2 requires some significant programming, if you are not prepared to undertake this then I recommend you not run the scripts.
Any ideas you have are deeply appreciated,