[A1kmm]

And a lot of applications can be easily sharded (e.g. between customers). So you can have a read-heavy highly replicated database that says which customer is in which shard, and then most of your writes are easily sharded across RDBMS primaries.

NewSQL technology promises to make this more automated, which is definitely a good thing, but unless you are Google or have a use case that needs it, it probably isn't worth adopting it yet until they are more mature.