If you're pushing the database up into the application layer, do you have to route all write operations through a single "master" application instance? If not, is there some multi-master scheme, and if so, is it cheaper to propagate state all the time than it is to have the application write to a master database instance over a network? Moreover, how does it affect the operations of your application? Are you still as comfortable bouncing an application instance as you would otherwise be?