i have reviewed the strace output helpfully provided by Fluora and most of it is taken up by repeatedly opening, reading, and closing the same index file over 26 thousand times. specifically, the file is opened, one chunk is read, then it is closed, and the process repeats. eventually it gets to reading 2 chunks on each iteration, and then 3, and so on
that seems like the problem! there's no reason to be repeatedly opening and reading a file from the beginning tens of thousands of times just for one search. and this does sound like an apt bug -- somehow it is deciding to just spin the same file read for 20 minutes, rather than just reading it once
