And there's also quorum commits too! Point is, these features aren't on by default, so you really have to know what you're doing, and not just assume you're safe because of the magic word "ACID".
MongoDB is actually strongly consistent in a single document, though. It uses Raft by default to replicate changes to all replicas. In practice, it has the A, C, and D of ACID for point writes.
Those are really some low expectations. The whole point of the ACID terminology is to apply it to transactions of arbitrary complexity with respect to the underlying data store.
It's not saying much to say that a database management system is ACID as long as you constrain your updates to a single record in a single table.
Sure. I actually agree, and like I said elsewhere in this thread, Postgres is my favorite database, and using it is something that I'd like to do for as long as possible. MongoDB's main selling point, after all, is expediency.
What I'm tired of is the rhetoric built upon the dichotomy that Postgres is ACID and MongoDB/NoSQL is not. As it stands, neither is, in any scalable fashion. And in no way is Postgres a panacea for every possible kind of data problem.
And like you said. It's not saying much to say that a database management system is ACID as long as you constrain your updates to a single machine.
There are better things on the horizon, databases that can actually do it all.
