Little known in the UK TiDB (soon to launch TiDB Cloud) is a significant change in how you think about traditional relational database- which typically can't scale horizontally.

TiDB: Distributed, horizontally scalable, MySQL compatible
- Morgan Tocker , TiDB talk at FOSDEM

TiDB promises (and delivers) on both these goals: A re-implementation of mysql , with the ability to add and remove nodes- think multi master.

Typically with database servers like Postgresql, or Mysql options for high availability are master / standby modes- there's no multi master support I'm aware of for Postgresql. Whilst mysql galera exists, the implementation of TiDB remains highly advantageous if you care about operational simplicity and scale out.

For more information see Morgan Tocker's talk about what is TiDB at Fosdem: