[vidarh]

Postgres is one of the best NoSQL datastores you'll find, until/unless you get to the point where scaling a single Postgres database becomes a problem.

But the point is 1) you're unlikely to ever get there. 2) if you're lucky enough to get there, if you start with your data in a structured database and gradually e.g. move things to JSON blobs in your Postgres DB, then move the things that really, seriously needs it off into a more easily shardable NoSQL datastore, it's a far easier direction to go in than the opposite.

Recovering structure when you've tossed it out the window is a massive pain.

And even a lot of the time when you end up needings things like e.g. ElasticSearch for search or something like that, it may still be better to keep the canonical data store in Postgres and stream changes to a secondary store to scale reads. Or add caching.

I'm not suggesting there are no cases where NoSQL datastores can't be the right choice from the beginning. But if you don't have a very compelling reason to, it's probably not.