I've been wondering myself if I've just got too much stored in the tracker sparql database. I seem to see my slowdowns and unresponsive apps when new items are being added, like incoming SMSs and new pictures I've just taken. It seems crazy that a database in 2016 would have trouble with just a few thousand entries, but I can't help thinking that it's just got poor index performance. WAG, I admit.

But the cache thing is an interesting alternate theory. I'm gonna try that myself and hopefully prove myself wrong about the DB.

Edit: BentL, what constitutes too low? I see memory free 163 of 885 mb and swap free 188 of 255 mb, but I don't know what it should be for optimum performance.