AppEngine Cold Starts
Posted by David Chandler on December 2, 2009
It appears that some of the startup delay I had previously blamed on GWT may actually have been due to the phenomenon that is popping up on the AppEngine forums lately. In order to conserve resources, AppEngine doesn’t keep your JVM “hot” unless it’s getting a lot of traffic, and it takes a few seconds to swap it back in. The resulting cold start delay, it would appear, is part of the price of “free.”
See this thread for more info.