[formerly_proven]

> That doesn't block writers (when the writer uses WAL)

Neither does VACUUM INTO or ".backup" (which uses the backup API) or sqlite3_rsync or litestream.

[andrewaylett]

I seem to recall having trouble with the read only flag and the backup API, but it's quite likely the problem was mine rather than with SQLite.

Anyway, the sync-friendly output is the really important part for me, because it means I can point borg at the zstd-compressed file and it'll only need to store what's changed.