MongoDB implemented a consistency level called causal consistency in 2017 (version 3.6). It’s quite a handy consistency level, strong enough for most applications and still performant. I helped design the API for causal consistency, but when we released it I dropped the ball and didn’t publicize or document it well. MongoDB’s causal consistency didn’t get the fame it deserved in 2017; I’ll try to rectify that now. MongoDB implements a Raft-like consensus protocol. Most people deploy...
