Nov 24, 2010

Re: Policy for instance startup

Not been a Googler can't help much with this.
Having said that, I suspect there is a kind of build in algorithm that
does some kind of application profiling taking into acount QPS,
response times, and other parameters which adjusts instance life time,
number of instances to start etc..
This could possibly explain the difference in behaviour between your
staging and production appls.

happy coding;-)

On Nov 23, 11:58 am, Tomas Alaeus <> wrote:
> I'm curious when exactly instances are started. I have two
> applications running on GAE, one of them have billing enabled. The one
> with billing enabled have been stress tested and have at most started
> 100 simultaneous instances. The other is just for testing and staging
> purposes and have never handeled much traffic.
> What I experience is that the staging server never starts more
> instances than needed. If a single person views pages it will never
> load more than a single instance. The other one however seems to start
> about 5 instances before anyone can get hot responses, and it will
> continue to start up to about 10 before realizing that ~1 QPS isn't
> that much traffic (the requests finish in about 100ms each).
> So, why does GAE boot up lots of instances even though 1 instance can
> serve the incoming traffic without a problem (the requests doesn't
> even overlap, so no waiting is needed)?
> I realize that this isn't a very big issue, since when it gets lots of
> traffic it will indeed need all the instances. I'm just curious why it
> happens.

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