Hello Takashi,
Is there a way to set a deadline for memcache? Does the pattern:
get from cache:
if not there, get from datastore:
store in cache
.. in a scenario where the memcache is down and the timeout to see that it
is down will degrade the app performance instead of make it better?
As we can see on the status dashboard, there was a huge increase in
memcache and datastore latency:
<https://lh6.googleusercontent.com/-GdRSS0CDCtM/T6mAOddnAHI/AAAAAAAAADo/4AyLDR-23hQ/s1600/Captura_de_tela-1.png>
<https://lh3.googleusercontent.com/-9WfMfqlOeGs/T6mAK0LOLjI/AAAAAAAAADg/sb0pN-TdiuM/s1600/Captura_de_tela.png>
Em quinta-feira, 26 de abril de 2012 15h08min16s UTC-3, Takashi Matsuo
(Google) escreveu:
>
> Hi Nathan,
>
> On Fri, Apr 27, 2012 at 1:17 AM, Nathan Skone <nsk...@headsprout.com>
> wrote:
> > Takashi,
> >
> > The latency spike stopped around 11:30pm PST. Can you tell what caused
> the
> > high latency, and if it is likely to occur again in the future?
> Occasional
> > spikes such as what happened yesterday would make the Google App Engine
> much
> > less useful to my company.
>
> First, are you really sure that the cause is in our side? Do you have
> any appstats results which show that any of your RPC calls don't take
> longer time than usual? If your RPCs take time, there are several
> things you can do to mitigate this. Do you set any deadline on your
> datastore calls? If no, you may want to set it appropriately, and when
> hitting the deadline, you can return a failure to your web clients and
> tell them to retry. Are you using urlfetch service to retrieve
> external resources? If so, sometimes those external resources can be
> the culprits. If you entirely rely your app's performance on the
> memcache service, which has no SLA, your app might see high latency
> when the memcache is flushed.
>
> In this particular case, as far as I know, there was no significant
> system issue around that time, so I don't think this was a system wide
> issue, and in such cases, please understand that we can not offer
> reports like that every time to every customers who experienced high
> latency(again, premier customers are different, at least to my
> knowledge).
>
> > I understand there is no SLA support channel for non-premium accounts.
> Does
> > that mean that us paying customers that cannot justify the extra $500
> > monthly fee cannot depend on any support from Google when experiencing
> > problems?
>
> No, not at all. There are still several options. You can use a new
> feature for reporting production issues in your admin console. You
> should be able to see a link 'Report Production Issue' on the right
> top side of your admin console, where you can report a production
> issue alongside of a screenshot with some highlights and privacy
> masks. That way, now you can report issues to us privately without
> revealing your app-id.
>
> Of course, you can also post here, then we offer a best effort
> support, like this ;)
>
> -- Takashi
>
> >
> > Thank you for your response,
> >
> > Nathan Skone
> > DYMO / Mimio - A Newell Rubbermaid Company
> >
> > On Wednesday, April 25, 2012 11:58:27 PM UTC-7, Takashi Matsuo (Google)
> > wrote:
> >>
> >> Hi Nathan,
> >>
> >> I think it's OK now. Are you still seeing this?
> >>
> >> BTW, this list is not a support channel with any kind of SLA. Now
> >> we're offering premier support for that type of demand.
> >> For more details about our premier support, please see:
> >> https://developers.google.com/appengine/docs/premier/
> >>
> >> Regards,
> >>
> >> -- Takashi
> >>
> >> On Thu, Apr 26, 2012 at 2:43 AM, Nathan Skone <nsk...@headsprout.com>
> >> wrote:
> >> > Application: hs-hbo
> >> > Datastore: High Replication
> >> > Normal latencies: 50ms-200ms
> >> > Today's latencies: 5000ms-10000ms
> >> > Idle Instances: ( Automatic – Automatic )
> >> > Pending Latency: ( Automatic – Automatic )
> >> >
> >> > Dear Appengine Team,
> >> >
> >> > This morning the latency of my application saw a sudden spike that
> has
> >> > made
> >> > it unusable for my company's purposes. How can I get assistance with
> >> > this
> >> > problem? This is an urgent issue that is directly effecting our
> >> > customers.
> >> >
> >> > Thank you,
> >> > Nathan Skone
> >> > DYMO / Mimio - A Newell Rubbermaid Company
> >> >
> >> > --
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> >> > "Google App Engine" group.
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> >> > https://groups.google.com/d/msg/google-appengine/-/O-GXusXXlzsJ.
> >> > To post to this group, send email to
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> >> > http://groups.google.com/group/google-appengine?hl=en.
> >>
> >>
> >>
> >> --
> >> Takashi Matsuo | Developer Advocate | tmat...@google.com
> >
> > --
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> >
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>
>
> --
> Takashi Matsuo | Developer Advocate | tmat...@google.com
>
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