At some point I thought I would be clever and just backup the file while no transaction is active (or manual WAL checkpointing and no WAL checkpointing active).

At some point I thought I would be clever and just backup the file while no transaction is active (or manual WAL checkpointing and no WAL checkpointing active). Ran into 2.2. https://www.sqlite.org/howtocorrupt.html https://www.sqlite.org/howtocorrupt.html -- the backup was close()ing the database file descriptor and canceling the SQlite locks.