We definitely get a spike on every new update. We are also adding new features that have to be added to every character as they login, which basically multiplies the spike's cost. However, we factor all that in while estimating what the DB load will be. It is not, as any DB person will tell you, an exact science. We've had half a dozen GUs since release, and yeah I'll certainly admit they haven't gone off without a hitch, but check out the release notes... it's a lot of changes that the design staff feel are vital to strengthening the game. As we go forward, the number of features we release with each GU will diminish, and you'll see this become more and more of a rarity.