The issue is not performance. The issue is backward compatibility. ALTER TABLE performance will eventually improve. PostgreSQL 9.1 lifts-off the lock-up limita

The issue is not performance. The issue is backward compatibility. ALTER TABLE performance will eventually improve. PostgreSQL 9.1 lifts-off the lock-up limitation. But what a performant ALTER TABLE will not improve is its intrusiveness to applications. When you change the schema you break the app. That's the problem. http://chronicdb.com/blogs/change_is_not_the_enemy http://chronicdb.com/blogs/change_is_not_the_enemy