yes, that insert is required
and just because it hangs on that query, it's not necessarily the cause, when you are at the 'cascade cliff'
you will find that different 'offending queries' start popping up too..
eventually the two BIG BAD queries will kill you -- showflat and postlist.. ( cfrm to a lesser degree, if you have a TON of forums ) those two, with the DESCending sort and lots of posts/topics and lotsa pagination, will become your bane...
analogy: you will find that you will be too busy mopping the floor to turn the faucet off
i've seen this play out on too many boards..
it essentially real good, until it gets real bad... there isn't much intervening time in the middle of the two..
ideally: linux server, apache 2.2+ php 5.3.13+, mysql 5.1+ with 4gb ram kicks a windows server butt with the same specs...
so i have given you my advice, based upon 100s of similar scenarios...
you will definitely find google-able good news and maybe you'll have a solution.. but my bet is you are about to hit a wall, if not already
