UBB.threads PHP Forum Software Community Forums UBB.threads 7 Bug Reports Non Bugs Query End hang on forum post

OK I know I've mentioned this in several other places but to keep it simple I decided to make a thread just for it. That way it's all in one spot and anyone else having this problem can find it here. I can also better track my (hopefully) progress in solving this.

Here's the issue.

I'm on UBB 7.5.7, PHP 5.4.9, MySQL 5.5.28.3, and FastCGI. These should all be the latest versions. My forum is running quite quickly in general. I get responses like this regularly now -

Generated in 0.809 seconds in which 0.745 seconds were spent on a total of 28 queries. Zlib compression disabled.

So the forum is flying.

However, when I make a new forum post, it hangs. It's not just slow. It locks and stays locked until it reaches whatever timeout value I have set.

I thought changing sql cache size to zero fixed it - it did temporarily. However now it's back to locking again.

I don't believe it's RAM. Here's a screenshot - I still have a quarter of my RAM open. It's not trying to use it. It is simply deadlocked.



So this lock happens both with SQL cache on and with it off.

My research up until now indicates it's a sign of two threads colliding and then staying in collision.

I will start testing and researching now to see what I can do to help this. It's happening on all my systems.