Yes I do see response times like this too -
Generated in 0.099 seconds in which 0.048 seconds were spent on a total of 14 queries. Zlib compression disabled.
So I am content with the overall speed.
I know you love the add-RAM solution
. However, I'm reading reports on the web with people hitting this issue with 32 gig of RAM and higher. So at least some portion of people have this query end hang issue even with far more RAM than I'll be adding.
The hang is always on updating UBB_Topics. Never anything else. Looking at the code, I'm seeing that the code inserts into UBB_Topics and then hard after that it updates UBB_Topics with the last PostID. It's that update that seems to be hanging. And it makes sense to me - MySQL is doing an insert on a row and that row is still being written when it tries to update it.
So here's a question. Do we really need that second update? If we're just setting the post_id and topic_last_post_id, can't we do that in the insert, instead of inserting a row and then immediately updating it? What's the purpose of hitting that same row twice in a row?
Or am I misreading what is happening?
