That seems dangerous? How can it be so? Surely multiple instances of SQLite shouldn't read the same backing file..

The whole job of sqlite is to handle the locking to keep such accesses safe.

Ok, I see. I did some reading and it looks like this to me:

* the DB is supported by a backing file

* this backing file supports multiple read threads simultaneously but writes are locked via filesystem locks

* write performance with multiple writers is therefore dangerous

* read performance is good if no one is writing and consistent even if someone is