This is part of an existing line of research going back decades. Fully self tuning database engines have proven to be a lot more tricky than you'd assume. It's

This is part of an existing line of research going back decades. Fully self tuning database engines have proven to be a lot more tricky than you'd assume. It's not the same thing as horizontal scalability. If you want to build a Spanner/Cockroach/Ti style system, you'll face the questions they're examining in detail in your per node storage engine. The empirical evaluation paper in particular is interesting and useful stuff.