> If you have to keep the initial requirement for your software, then SQLite is completely out of equation.

No it isn't? You can run a thin sqlite wrapping process on another server just fine. Ultimately all any DB service is, PostgreSQL included, is a request handler and a storage handler. SQLite is just a storage handler, but you can easily put it behind a request handler too.

Putting access to sqlite behind a serial request queue used to be the standard way of implementing multi-threaded writes. That's only spitting distance away from also putting it behind TCP.

You could do that, but you'd run into exactly the same bottleneck the author describes with a remote Postgres instance. The workload exposes high contention on hot rows. If transactions are kept open for several milliseconds due to this being a remote network call between client and DB server, throughput will be equally limited also when using SQLite.

As long as WAL mode is not enabled, connections over NFS/SMB or other file sharing protocols will work.

I'm not saying that this is a good idea, and it could fail in a spectacular manner, but it can be done. DML over this is just asking for trouble.

Exactly. People forget that “SQLite can’t do X” often really means “SQLite doesn’t ship with X built in.” If you wrap it with a lightweight request handler or a queue, you essentially recreate the same pattern every other DB uses. The fact that PostgreSQL bundles its own coordinator doesn’t make SQLite fundamentally incapable. It just means you choose whether you want that layer integrated or external.

Well that's just dqlite/rqlite.