This is do-able with FoundationDB. You could distribute your application colocated with the database nodes and write a router to redirect requests to the machin

This is do-able with FoundationDB. You could distribute your application colocated with the database nodes and write a router to redirect requests to the machine which owns the data you're looking for. Then your application logic is computing against data on the same machine. FoundationDB exposes the key-range to node mapping to you to make this router possible.