Tim, your app is probably not doing much urlfetching?
We have an app (h-script) that performs several urlfetch operations
per task. We are talking to other Google services only. On a good
day, each task takes between 3 and 10 seconds. This goes up to 20
seconds sometimes. The CPU time for the tasks is minimal - 60-100
ms. It's all spent in urlfetch.
This should present GAE with no problem - we time out gracefully, etc.
Trying to run this full bore (several queues, 50/s) results in 98+%
task failure rate.
Running across 5 queues and at 6/m drops that to about 30% failure
(and MUCH longer processing time obviously). With the back-off
kicking in, some tasks end up running all day. I understand the 1sec
rule, but it supposedly does NOT apply to tasks. And with a
dependence on urlfetch, there is no way to optimize to that level.
As it stands, there is either a bug in there somewhere triggering a
clampdown erroneously, or a limiter Google has not documented... In
either case, it makes it very difficult to do certain things that GAE
should be awesome at. I would guess your usecase is different..?
J
On Aug 26, 8:24 pm, Tim Hoffman <zutes...@gmail.com> wrote:
> Unfortunately you haven't provided a great deal of information about
> what you are doing in your tasks.
>
> My guess is whatever you are running in the task is just taking too
> long.
>
> Queued will retry unless you exit cleanly. And each failed tasks time
> between retries will
> will increase.
>
> You should put some logging in your task to see where it is getting
> too. Then you will have some idea
> where the bottleneck is.
>
> The task queue subsystem is in my experience quite robust and reliable
> if you
> code you tasks taking into account its limitations.
>
> Regards
>
> Tim
>
> On Aug 26, 2:06 pm, "Jan Z/ Hapara" <jan.zawad...@gmail.com> wrote:
>
> > Not relevant unfortunately.
>
> > There is not try / catch here - when this happens, your code doesn't
> > even start executing - GAE just fails it outright, and worse yet, the
> > back-off algorithm kicks in so after a few generations the whole thing
> > degenerates into uselessness (I've seen tasks that fail with this
> > error 23 times in a row)
>
> > Jan
>
> > On Aug 17, 6:58 am, Alon Carmel <a...@aloncarmel.me> wrote:
>
> > > When you fetch data from another server you use the urlfetch service. url
> > > fetch service holds another limit for requests. when you relay on external
> > > servers they hold another load which you cannot expect on your end. so if
> > > an
> > > external service has some latency suddenly and plus fall under a database
> > > high load your tasks will fail enventually.
>
> > > try
>
> > > catch
>
> > > :)
>
> > > -
> > > Cheers,
>
> > > def AlonCarmel(request)
> > > import simplejson as json
> > > contact = {}
> > > contant['email'] = '....@aloncarmel.me'
> > > contact['twitter'] = '@aloncarmel'
> > > contact['web'] = 'http://aloncarmel.me'
> > > contact['phone'] = '+972-54-4860380'
> > > return HttpResponse(json.dumps(contact))
>
> > > * If you received an unsolicited email from by mistake that wasn't of your
> > > matter please delete immediately. All E-mail sent from Alon Carmel is
> > > copyrighted to Alon Carmel 2008. Any details revealed in e-mails sent by
> > > Alon Carmel are owned by the Author only. Any attempt to duplicate or
> > > imitate any of the Content is prohibited under copyright law 2008.
>
> > > On Sat, Aug 14, 2010 at 8:28 PM, Dmitry <dmitry.lukas...@gmail.com> wrote:
> > > > Hi app team!
>
> > > > "Request was aborted after waiting too long to attempt to service your
> > > > request. This may happen sporadically when the App Engine serving
> > > > cluster is under unexpectedly high or uneven load. If you see this
> > > > message frequently, please contact the App Engine team."
>
> > > > What may cause this error? I'm getting this quite often (may be every
> > > > 1 minute) when using task queue. Queue rate isn't so big (5-7
> > > > simultaneous requests, ~10 sec in average). Task just fetchs data from
> > > > another server and processes it.
>
> > > > thx
>
> > > > --
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