Not sure if a bug, but an observation for real.
I just tried to delete tiles of several online providers from the cache (~200MB whole cache file size) and it was not a very good experience. The phone became sluggish and almost hangs, so I waited for five minutes then closed the app and deleted cache file manually.
It's all really weird, sqlite shouldn't be that hungry.
@Orux, have you tried to switch sqlite to WAL mode and set synchronous to normal (or even off)? I'm afraid that now this function is raping SD-card.