When you give up one of the major components of relational databases like foreign keys you pick up lots of performance opportunity.
It is amazing what Vitess / PS will help you accomplish but they don't talk a lot about tradeoffs you make to get there (which are similar to what you face with sharding MySQL without additional tooling).
It is amazing what Vitess / PS will help you accomplish but they don't talk a lot about tradeoffs you make to get there (which are similar to what you face with sharding MySQL without additional tooling).