I agree that the three areas outlined in the article are things that MongoDB got right: a structured query language (instead of a textual query language), replica sets, and the oplog.<p>But the lack of transactions over multiple documents (in the same shard at least) and the lack of joins over multiple collections are a big showstopper for the kind of applications I develop.<p>I note that solutions like YouTube&#x27;s Vitess provide something similar to MongoDB&#x27;s replica sets.<p>I also note that PostgreSQL&#x27;s logical decoding provide the same functionality than MongoDB&#x27;s oplog tailing.