Key quote: "The only time that a CAP-Available system would be available when a CAP-Consistent one would not is when one of the datacenters can’t talk to the o

Key quote: "The only time that a CAP-Available system would be available when a CAP-Consistent one would not is when one of the datacenters can’t talk to the other replicas, but can talk to clients, and the load balancer keeps sending it traffic. By considering the deployment as a whole, high availability can be achieved without the CAP theorem’s requirement of responses from a single partitioned node." It is true that if you assume your client app is not important that a CP system is the right choice. And I would also say this /was/ true up till about 2004 when Gmail was released. But it definitely stopped being true in 2007 when the iPhone was released and you started having installed apps. Since then, users have slowly grown to expect both mobile apps and SPAs to work regardless of whether the servers work, regardless of load balances, regardless of connectivity. If you look at the market trends, things are increasingly going in this direction. From self-driving cars, to IoT devices, to drone delivery, to even traditionally server-dependent productivity tools like gDocs and others - people need to get work done even if the internet to your server doesn't exist. Will banking applications still need mostly server-dependent behavior? Yes. Is CP still important? Yes. But it is biased to say that CP systems are better. Choose the right tool for the right job. CockroachDB and RethinkDB are definitely the right choice for a strongly consistent database, but they aren't the right choice for everything. My database is an AP system, but it should not be used for many apps out there. Neither of these are "better", they are just tradeoffs you have to decide upon.