Goodbye, Google App Engine

App Engine is optimized for applications with short-lived requests, typically those that take a few hundred milliseconds. An efficient app responds quickly for the majority of requests. An app that doesn’t will not scale well with App Engine’s infrastructure.

The Unofficial Guide to Migrating Off of Google App Engine

One would think that any database backed by Google would be robust. After all, this is the same code powering apps like Gmail. For whatever reason, however, the GAE database has extraordinarily high variance. Requests will inexplicably go from tens to thousands of milliseconds to serve. At a high load (50+ requests/sec), we saw database timeouts tens of times per minute, and often more (every request in a 10-60 sec period would fail).