There is no free lunch with databases. I often argue the position that master-master is overrated, because you have to design your application around the constr

There is no free lunch with databases. I often argue the position that master-master is overrated, because you have to design your application around the constraints to see the benefits and avoid the pitfalls. Same thing with CockroachDB Postgresql "wire protocol support". The fact that it only supports "serializable" isolation level when Postgresql utilizes Read Committed OTB should be a screaming red flag to just about anyone that you are in for some challenges on the performance front. Some well-worn modeling techniques are simply infeasible under typical workloads at that isolation level, for one. Starting with bog-standard RDBMS you have to be deliberate to get great performance. Adding in extra, fancy scaling properties means even more considerations to take into account to maintain consistency while achieving gains.