Hi All
> Actually, the default limit is 30 active requests.
> I can only reach 10 active requests without error.
Same here. I've been checking the instance count on my Task Queue
servlet and I've never seen it exceeds the 10 instance limit. There
are two other App Engine developers on my twitter TL who are also
experiencing the 10 limit. What's this? What's the relation between
"30 active requests" and the number of instances? Since an App Engine
Java instance can only run one request at a time, there should be 30
instances to handle 30 active requests.
Actually, it was 16 last year - I and another developer was observing
a 16 instance limit when you make your servlet busy with TQ or many
client requests. I've been thinking it must be a some kind of internal
safe valve. Is it possible to extend that by submitting a request to
Google? So that we can use TQ as a mean of large distributed batch
processing just like MapReduce.
Thanks,
Kaz
On Mar 3, 12:45 am, Gary Orser <garyor...@gmail.com> wrote:
> But that's the point. I can not reach 30 active requests.
> I can only reach 10 active requests without error.
>
> Any ideas on how I can debug this?
>
> Cheers, Gary.
>
> On Mar 2, 7:05 am, "Nick Johnson (Google)" <nick.john...@google.com>
> wrote:
>
> > Hi,
>
> > On Tue, Mar 2, 2010 at 1:54 PM, Wooble <geoffsp...@gmail.com> wrote:
> > > The 500 requests per second number relies on the probably-unreasonable
> > > assumption that each request can complete in ~75ms. Deliberately
> > > making your requests take a whole 3 seconds each is, obviously, not
> > > going to work. You can only have 10 instances active at a time by
> > > default; if the pages you're serving actually take 3 seconds to
> > > complete you'll need to optimize things a whole lot or be stuck with a
> > > 3.33 request/sec maximum.
>
> > Actually, the default limit is 30 active requests.
>
> > -Nick Johnson
>
> > > On Mar 1, 11:33 pm, Gary Orser <garyor...@gmail.com> wrote:
> > > > Hi Nick,
>
> > > > Hmm, I was running tests on a billing enabled appspot today. 100
> > > > requests/test.
>
> > > > 10 threads getting a URL with a 3 second sleep (to emulate
> > > > computation) on appspot, was the most I could get without getting 500
> > > > errors.
> > > > If I raised the thread pool beyond 10, I started getting errors??
>
> > > > That doesn't reconcile very well with this statement from the
> > > > appengine website.
> > > > "Requests
> > > > The total number of requests to the app. The per-minute quotas for
> > > > application with billing enabled allow for up to 500 requests per
> > > > second--more than one billion requests per month. If your application
> > > > requires even higher quotas than the "billing-enabled" values listed
> > > > below, you can request an increase in these limits here.
> > > > "
>
> > > > Is there some billing setting that affects this?
>
> > > > Cheers, Gary
>
> > > > PS. dead simple request handler.
>
> > > > import time
> > > > from django import http
> > > > def sit(req):
> > > > time.sleep(3)
> > > > return http.HttpResponse('foo')
>
> > > > errors are:
>
> > > > 03-01 04:15PM 48.177 /sit/91 500 10019ms 0cpu_ms 0kb gzip(gfe)
> > > > 153.90.236.210 - - [01/Mar/2010:16:15:58 -0800] "GET /sit/91 HTTP/1.1"
> > > > 500 0 - "gzip(gfe)" ".appspot.com"
> > > > W 03-01 04:15PM 58.197
> > > > Request was aborted after waiting too long to attempt to service your
> > > > request. Most likely, this indicates that you have reached your
> > > > simultaneous dynamic request limit. This is almost always due to
> > > > excessively high latency in your app. Please seehttp://
> > > code.google.com/appengine/docs/quotas.htmlfor more details.
>
> > > > On Mar 1, 2:36 pm, Michael Wesner <mike.wes...@webfilings.com> wrote:
>
> > > > > Correction/addition to my last email.
>
> > > > > It turns out that our requests for this EC2 pull thing are actually
> > > much faster now. Gary and our other devs have reworked it. I need
> > > updated
> > > numbers, but they don't take 10s, probably more like 2s. We still have
> > > some
> > > heavy ~5s services though, so the same issue exists with the simul-req
> > > stuff, just to less extent. We don't actually hit this limit much now
> > > with
> > > the current beta that is in production, but it is low traffic at the
> > > moment.
> > > We are just getting ready to ramp up heavily.
>
> > > > > I asked Nick what we should do, well just today after my last email, I
> > > have made contact with a Developer Advocate and whatnot, which is
> > > fantastic.
> > > It looks like we, as a business, will be able to have better contact
> > > with
> > > the GAE team. We would very much like to continue working with you to
> > > figure
> > > out what actions we can take and what provisioning we can do to make our
> > > product successful and scale it as we grow in the near future. Gary Orser
> > > will be replying to this thread soon with more findings from both our real
> > > app code and a little test app we are using and which he will share with
> > > you.
>
> > > > > We plan on having a presence at Google I/O this year as we did at
> > > PyCon. Hopefully we can even get setup in the demonstration area at I/O.
>
> > > > > Thanks Nick for your help. Could we possibly setup a quick skype conf
> > > call at some point?
>
> > > > > -Mike Wesner
>
> > > > > On Mar 1, 2010, at 1:13 PM, Michael Wesner wrote:
>
> > > > > > Nick,
>
> > > > > > If we (I work with Gary) require fairly heavy requests which run for
> > > multiple seconds then it is not possible to get anywhere near 400 QPS.
> > > The
> > > math used on the docs page only applies to 75ms requests.
>
> > > > > > (1000 ms/second / 75 ms/request) * 30 = 400 requests/second
>
> > > > > > so lets say each request takes 10 seconds (and ours, pulling data to
> > > EC2 for a heavy operation that we can't do on GAE could take that much
> > > since
> > > we have to process and update some XML before sending it)
>
> > > > > > (1000 ms/second / 10000 ms/request) * 30 = 3 requests/second
>
> > > > > > And that does not even take into account all the other traffic to
> > > > > > our
> > > application, nor the fact that many users could be doing this same heavy
> > > operation at the same time. Our application will see spikes in this type
> > > of
> > > activity also. The docs also mention that CPU heavy apps incur penalties,
> > > which is vague and scary.
>
> > > > > > Great effort is put into doing things in the most efficient way
> > > possible, but not everyones apps can do everything in 75ms. Most all of
> > > our
> > > service calls are under 250ms. We do have a little overhead from our
> > > framework which we are constantly working on improving. Our application
> > > is
> > > AMF service/object based which is inherently heavy compared to simple web
> > > requests. It limits the amount of memcache work we can do also, but we
> > > are
> > > also working on improving our use of that.
>
> > > > > > We easily hit these boundaries during testing so I think we really
> > > need much higher simultaneous dynamic request limits for not only our
> > > production instance but our dev/qa instances so we can test and load them
> > > to
> > > some degree. Our QA team could easily bust this limit 20 times over.
>
> > > > > > So, Nick Johnson... I ask your advice. We are running a
> > > company/product on GAE. We are more than happy to pay for
> > > quota/service/extra assistance in these matters. What do you suggest we
> > > do?
>
> > > > > > I should also mention that I spoke with Brett Slatkin at PyCon and
> > > > > > he
> > > is now at least semi-familiar with the scope of product we have developed.
> > > I have exchanged contact info with him but have not heard anything back
> > > from him yet. We would really appreciate contact or even a brief meeting
> > > at
> > > some point (in person or otherwise).
>
> > > > > > Thanks,
>
> > > > > > -Mike Wesner
>
> > > > > > On Mar 1, 2010, at 7:40 AM, Nick Johnson (Google) wrote:
>
> > > > > >> Hi Gary,
>
> > > > > >> Practically speaking, for an app that hasn't been given elevated
> > > permissions, you should be able to have at least 30 concurrent requests -
> > > equating to around 400 QPS if your app is fairly efficient. What problems
> > > are you running into that lead you to conclude you're hitting a limit at 4
> > > QPS, and that the problem is at App Engine's end?
>
> > > > > >> -Nick Johnson
>
> > > > > >> On Sat, Feb 27, 2010 at 8:23 PM, Gary Orser <garyor...@gmail.com>
> > > wrote:
> > > > > >> Hi all,
>
> > > > > >> We were trying to create programmatic parallel access to our
> > > appengine
> > > > > >> application.
>
> > > > > >> From EC2, we were attempting (with threads) to run parallel access
> > > > > >> (url gets/posts) to
> > > > > >> our appid. There are some long running processes that we need to
> > > run
> > > > > >> on EC2, for which
> > > > > >> we would like to get a bunch of information (entities + processing
> > > on
> > > > > >> appspot) quickly.
>
> > > > > >> We seem to be running into a limit on the number of accesses that
> > > are
> > > > > >> allowed.
> > > > > >> (4 threads seems to be the effective limit)
>
> > > > > >> Is there some sort of denial of service limit imposed on multiple
> > > > > >> accesses from a single IP?
>
> > > > > >> Cheers, Gary
>
> > > > > >> --
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> > > > > >> --
> > > > > >> Nick Johnson, Developer Programs Engineer, App Engine
> > > > > >> Google Ireland Ltd. :: Registered in Dublin, Ireland, Registration
> > > Number: 368047
>
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