Google I/O 2011: Scaling App Engine Applications
Why Stack Overflow recommends it
Stack Overflow users link it when answering App Engine scheduler, instance scaling and quota questions, since it explains how request dispatch and edge caching behave.
Recommended by 2 people across 2 different months, 2011 to 2012.
What it is
A Google I/O 2011 session by Justin Haugh and Guido van Rossum on building highly scalable App Engine apps. It covers how instances are allocated as traffic grows, low latency and memory use, concurrency, async APIs, load testing, profiling, and pitfalls like entity contention and hot tablets.
What people said
Strong rec Julian Go · 2011-05 · Stack Overflow · on “Appengine Optimizations”
This is not really an optimization but the choice of framework is really important here. Most legacy framework in Java and Python(Django,..) are not designed to startup fast because it just isn't important in traditional hosting. Consider using an App Engine specific framework like Tipfy, Kai, Webapp, ... (Python) or slim3, ... (Java). Ideally, you should organize your data so that each user request needs only one call to the datastore, preferably a db.get because queries are significantly slower. To achieve this, you'll often need to denormalize your data, and maintain the different copies in sync using entity groups and transactions. When making more than one urlfetch or API call, you can
Recommends Guido van Rossum · 2012-03 · Stack Overflow · on “Criteria for dispatching requests for multi-threaded GAE apps”
When I said "benchmark" I meant to measure the variables you are interested in, not just profile your code. We cannot publish the algorithm because it frequently changes and because the input to the scheduler contains many measurements of your app's performance that are hard to track back directly to your code. The behavior is also affected by datastore performance which depends on many variables. For more info on the scheduler, see the video of the talk that Justin Haugh and I did at Google I/O 2011 on scaling app engine apps: [this video]
Cites Mark Ivey · 2012-02 · Stack Overflow · on “How much QPS can I expect from App Engine's daily free quota?”
Thanks for the FAQ link, that's helpful. Edge caching is only enabled for paid apps. Free appengine apps don't get it, according to this Google I/O talk: [this video]