App Engine HTTP 500s
I agree that the correlation between startup log messages and 500 errors is not necessarily causal. However, it could be and pocoa should take steps to ensure that his startup time is low and that time consuming tasks be deferred when possible.
One log entry and one 500 error does not mean much, but a few with time correlated probably points to excessive startup costs.
This request caused a new process to
  be started for your application, and
  thus caused your application code to
  be loaded for the first time. This
  request may thus take longer and use
  more CPU than a typical request for
  your application.

I've handled all the situations, also DeadlineExceededError too. But sometimes I see these error messages in error logs. That request took about 10k ms, so it's not exceeded the limit too. But there is no other specific message about this error. All I know is that it returned HTTP 500. Is there anyone know the reason of these error messages?
Thank you.