Hi Anand,

Thank you for the response.

I am not concerned with being charged for the full 15 minutes for when
instances start and stop (or as you described), what I am concerned
with is the start-up time it takes each time an instance is fired up.
A browsing session while testing looks something like this;
1. Click a link.
2. Wait 3 seconds for an instance to fire up, get to look at a web
page.
3. Study web page for 5 seconds, click on link.
4. Wait 3 seconds for an instance to fire up.
5. Repeat.

In regards to idle instances it appears to me that they are getting
stuck about once a day or so until I manually intervene.
Originally Google App Engine was billed as going to have an always on
feature but now it appears I have two choices;

Choice 1. Pay nothing and get ridiculous latency that makes GAE look
like something that nobody in their right mind would want to use.

Choice 2. Pay $1.60 ($.80 until December 1) a day for a usable testing/
development platform.

For a low traffic site the cheapest anyone can expect to pay is $48 a
month. This is a far cry from the $9 a month always on feature that
was offered all those months ago.

I hope these are just teething errors that are occurring with Python
2.7. As you did point out it is still experimental. I am going to
assume that this will all be fixed sometime soon.

Other than the issues above, I have been pleasantly surprised with how
well Python 2.7 is performing. The amount of traffic a single instance
can take is quite surprising, especially when compared to how GAE was
working with Python 2.5


On Nov 22, 6:51 pm, Anand Mistry <[email protected]> wrote:
> On Monday, 21 November 2011 10:25:34 UTC-8, WallyDD wrote:
>
> > I am little confused with how these instances work.
>
> > How long does an instance stay alive?
> > A site in Python 2.5 (M/S) fires up an instance when it is accessed
> > and the instance stays alive for minutes after.
> > With Python 2.7(HRD) the instance is killed off after a matter of
> > seconds. So I either have to pay and keep the application alive but
> > then it gets tricky.
> > And to add insult to injury, if I access a python 2.7 application and
> > get one page, the instance lasts for a few seconds but I am billed for
> > 15 minutes. If I am billed for 15 minutes please would it be possible
> > for the instance to stay alive for something close to 15 minutes?
>
> For Python 2.7 specifically, we're aware of the short instance life. Please
> be aware that the Python 2.7 runtime is still experimental and so rough
> spots like this can happen.
>
> As for billing, remember, you only get charged the 15 minutes once per
> instance. If that instance goes away and comes back within 15 minutes, you
> don't get charged again.
>
> > Now if I enable billing (for the cost of $2.10 a week).
> > I can adjust the sliders under application settings, I have two
> > settings "Idle instances" and "Pending latency".
>
> > Leaving "Idle instances" at Automatic results in instances only
> > lasting a few seconds. Setting it to 1 results in having a "Resident"
> > instance and this sort of works. I can use the application a little
> > but then a second instance fires up and leaves one instance completely
> > idle. All I want is one instance running. I put "Pending Latency" up
> > to 500ms to try and stop other instances firing up.
>
> I believe (I'm not an expert here) the purpose of "Idle Instances" is to
> absorb extra traffic to help your app scale more smoothly. Once you start
> using that instance, it's no longer idle so the system spins up another
> instance.
>
>
>
>
>
>
>
> > I use the application and so now I have two instances serving, The
> > resident instance is sitting there doing nothing and I am using
> > another instance but being billed for both.
> > So I go an play with the sliders and set idle instances to automatic
> > and it kills one off (the resident one that was doing nothing). But
> > then the instances start with their stop start routine and the
> > application is very unresponsive.
>
> > Is there a bug with the instancing or is there something that I really
> > don't understand here.

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