Re. #1, can you elaborate? The tracking issue for this is still open[1]. As far as I can tell this is a hard blocker for any use case where a random user on the web can connect to NATS, since it means that user can wiretap any room without knowing the room ID.
Re #2, the problem is that a rollup of a subject in NATS rolls up the whole subject, so there’s a race condition if you try to use it the way DriftDB uses it. If one client is computing a compaction while another client sends a message, that message will be erased by the compaction.
This works if a single producer is writing to a stream, because that producer can stop emitting messages during the compaction. But in our case, each client can produce messages at any time.
DriftDB solves this by sending a sequence number alongside the rollup of the last message included in the rollup, and the server preserves messages after that sequence number.