[manigandham]

There's no reason for eventual consistency. Firestore is backed by BigTable and Spanner (both strongly consistent just like Postgresql). There's nothing magic about this - it just provide a pub/sub channel on the watched keys and automatically does a SELECT loop in the background once an INSERT triggers that key.

You can do the same thing on a simple by selecting by a `chatid` in a table that'll get the latest messages/inserts. Again, the only thing needed is the pub/sub layer, not an entirely different database.