I am not sure if I am doing something wrong, but basically for the duration of initial scan, the database was writing to disk … a lot, about 1/10 to 1/20 of scanned volume. So when I scanned ~800GB of files, my poor SSD got trashed 40-80GB of writes over relatively short period of time. And knowing how SSD write lifetimes are, I find it slightly disturbing.
Is it feature or bug? It seems like bug to me, e.g. the database writes should be within orders of magnitude of final database size and committing every small change to disk seems overkill.