This isn't theoretical; many companies do PostgreSQL async 1:N physical replication, by using e.g. https://pgbackrest.org/ https://pgbackrest.org/ to have the p

This isn't theoretical; many companies do PostgreSQL async 1:N physical replication, by using e.g. https://pgbackrest.org/ https://pgbackrest.org/ to have the primary push WAL segment files (a.k.a. "the last n milliseconds of packets" in the write-ahead log) as objects to S3. All the read-replicas then independently discover the new objects in S3 as they become available; fetch them; and replay them. > You could do even better if you out-of-band signal the readiness so you do not need to poll while idle. S3 and its clones have "object lifecycle notifications", where you can be informed by a push-based mechanism whenever a new object is put into the bucket. But — what do you have to do, to get these notifications? Subscribe to a real message queue, that S3 puts these notifications into. So using it here would be somewhat cheating ;)