Oct 27, 2010

maximum number of requests that may be handled in a single process lifetime

I was doing some load tests on app engine today when I noticed a new Info message in the logs: "After handling this request, the process that handled this request reached the maximum number of requests that may be handled in a single process' lifetime, and exited normally."

So what that supposed to mean ?
Up to know we new that application instances are automatically terminated after some inactivity time out. If I understand this message well now we know that a process can be terminated after handling so many requests. How many exactly ? is this a new magic number ? Lets hope we will have some definite answers from the always helpful App Engines team.

I am doing some latency optimization (lazy imports) in this app based on the assumption that an instance will stay live as long as there are more requests coming in and I was scared this new number spoils my optimization logic. After some more testing I have found out that this is not true since whatever this number is it must be in the order of thousands requests - so no big trouble in my use case. Still I think App Engine's developers deserve to know more about such parameters, it helps both developers and the platform.

Oct 23, 2010

Downloan app code feature or bug ? - download_app

I think App Engines developers community has by a vast majority rejected the idea of code downloading at least as default (opt out) option.
I also do not like the idea of a payable service, since it :
  • will complicate the pricing model
  • will attract criticism against the platform and 
  • help guys who are in the business of doing unreasonable GAE vs S3 vs whatever_looks_like_cloud comparisons happy.
But ... then again who am I to tell mother G what to do ? -:)
( see my post at google-appengine group )

Oct 15, 2010

Instances console in App engine's Admin Tools

It seems a new feature has just been rolled out in App Engine's production Admin tools - instances - it shows a view of total running instances along with QPS, Latency and memory used Memory as well as averages for the above values.
There is also a summary of the above in application's dashboard.
It is a very useful feature that will help a lot with application performance monitoring and resolving issues on when and how many new instances are started and killed.
Well done dev team. :-)