For what it's worth, you can most definitely do that with Oracle. I can't speak to Postgres scalability, but it is my DB of preference. (I guess it might have

For what it's worth, you can most definitely do that with Oracle. I can't speak to Postgres scalability, but it is my DB of preference. (I guess it might have something to do with the fact it's as close to Oracle as you're going to get in Open Source). We design apps to treat the datasource as a network service, and have no problems load balancing DB connections across our database cluster, and adding new DB nodes as required. The biggest problem I've seen is the relative lack of support for Oracle in something like Rails, or non-Oracle app servers in general. I've had to custom write some connection pool failure detection for a few apps to deal with cluster failure (something that comes out of the box with the Oracle app server, but we wanted to use JBoss and GlassFish), so while it's not perfect, it's most definitely doable. Just because his particular architecture or offering doesn't fit well with typical database deployment architectures, doesn't mean that "SQL doesn't scale".