So after I upgraded to iTunes 10 and did the necessary bits of extra hackery to make the UI reasonable again, iTunes decided to lose track of my AppleTV (probably as a result of my fiddling with plists to try to fix this annoying regression), which forced me to do a full re-sync of my entire library.
Three days later (I pushed around 165GB over my wireless network), the sync was complete, but I noticed a giant 282GB blob of "Other" stuff on the disk allocation graph in iTunes. When I logged into the AppleTV to see what was going on, I discovered that during the sync process, something was causing my AppleTV to drop 78MB
iTunesDB.tmp files in my
A lot of them.
Just north of 3600, in fact.
So... yeah, there's my 280+ GB of "Other". Ouch! So much for that nice new 500GB external drive! My initial testing didn't seem to indicate that their presence or absence mattered at all for normal use, so I nuked them and freed up a ton of disk space. I have observed that I get one to three more of them every time iTunes syncs to the AppleTV, though, so eventually they'll be a problem again.
Does anyone know what these files are or why they're written to disk during syncs? Or more importantly, do you know what should be--but clearly isn't--cleaning them up?