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.
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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