On high traffic App Engine applications, you may occasionally see a request fail with error code 202. You’ll see the following text in your logs:
A problem was encountered with the process that handled this request, causing it to exit. This is likely to cause a new process to be used for the next request to your application. (Error code 202)
The request log will look similar to the picture below:
Error code 202 is an internal App Engine failure code: an unknown error occurred within App Engine or its associated services, not from your application. This is not an error that your application can catch or recover from, nor is the application at fault for this error. The current request will fail, but the client is free to retry the request. If this request is from the task queue service, the task queue will automatically retry the request if you set the appropriate settings while creating the task.
A note about error codes: the code 202 relates to App Engine; it is NOT a HTTP status code. When a request encounters this internal error, it fails with the HTTP status code 500 (as you can see from the above picture).