Eli,

You have the python request server.
Here is the java client:
You'll have to get the libraries yourself.

Cheers, Gary

import java.util.ArrayList;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

import org.apache.commons.io.IOUtils;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.conn.params.ConnPerRouteBean;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class Main
{
        private Log log = LogFactory.getLog(Main.class);
        // ADJUST: number of threads to make requests on
        public static int NUM_PARALLEL_SECTION_REQUESTS = 20;
        public static HttpParams httpParams = new BasicHttpParams();
        {
                httpParams.setBooleanParameter("http.protocol.expect-
continue", false);
                // ADJUST: if this is included, will use 8888 as a
proxy port. Charles Proxy defaults to this port.
                //httpParams.setParameter("http.route.default-proxy",
new HttpHost("localhost", 8888));
        }

        protected class GetSection implements Callable<String>
        {
                protected int index;
                protected HttpClient client;
                protected String URL;
                public GetSection(int index, HttpClient client, String
URL)
                {
                        this.index = index;
                        this.client = client;
                        this.URL = URL;                }
                public String call() throws Exception
                {
                        HttpGet getSection = new
HttpGet(URL);                        HttpResponse respSection =
client.execute(getSection);
                        String foo =
IOUtils.toString(respSection.getEntity().getContent(), "UTF-8");
                        return foo;
                }        }

        public static void main(String[] args) throws Exception
        {                new Main().maint(args);
        }

        public void maint(String[] args) throws Exception        {
                SchemeRegistry schemeRegistry = new SchemeRegistry();
                schemeRegistry.register(new Scheme("http",
PlainSocketFactory.getSocketFactory(), 80));
                schemeRegistry.register(new Scheme("https",
SSLSocketFactory.getSocketFactory(), 443));
                HttpParams params = new BasicHttpParams();
                ConnManagerParams.setMaxTotalConnections(params,
NUM_PARALLEL_SECTION_REQUESTS);
                ConnManagerParams.setMaxConnectionsPerRoute(params,
new ConnPerRouteBean(NUM_PARALLEL_SECTION_REQUESTS));
                HttpProtocolParams.setVersion(params,
HttpVersion.HTTP_1_1);
                ClientConnectionManager cm = new
ThreadSafeClientConnManager(params, schemeRegistry);
                HttpClient client = new DefaultHttpClient(cm,
httpParams);

                ExecutorService es =
Executors.newFixedThreadPool(NUM_PARALLEL_SECTION_REQUESTS);
                // ADJUST: total number of requests to make.
                int numSections = 100;
                ArrayList<Future<String>> futures = new
ArrayList<Future<String>>(numSections);
                log.info("queuing requests");
                for (int i = 0; i < numSections; i++)
                {
                        // ADJUST: set a real hostname here
                        futures.add(es.submit(new GetSection(i,
client, "http://yourappid.appspot.com/sit/"; + Integer.toString(i))));
                        // ADJUST: stagger initial requests with this
sleep
                        //Thread.sleep(200);
                }

                es.shutdown();

                log.info("waiting for thread pool to finish");
                while (!es.isTerminated())
                        Thread.sleep(500);

                log.info("all requests queued");

                try
                {
                        for (Future<String> future: futures)
                                future.get();
                        log.info("got all futures");
                }
                catch (ExecutionException e)
                {
                        // TODO: not really sure what to do if cause
is Throwable but not Exception
                        if (e.getCause() instanceof Exception)
                                throw (Exception)e.getCause();
                }
        }

On Mar 2, 9:50 am, Eli Jones <eli.jo...@gmail.com> wrote:
> What I'm suggesting is.. You need to create a simple test setup that
> recreates this dynamic request limit error.. (It definitely should not
> take 8mb of code).
>
> I will see if I can create a handler like the one you posted, deploy
> it, and then run 30 seperate processes that keep getting from that
> handler.. (I can write this up in less than 10kb or python code)...
>
> My guess is this will work.  Without seeing sample code.. I can't tell
> where you may be going wrong (or where GAE may be breaking)
>
> On 3/2/10, Gary Orser <garyor...@gmail.com> wrote:
>
>
>
> > Actually, 4 threads was before we optimized server side, and set up
> > the test environment.
>
> > I have a tarball, about 8mb, with the test environment. (django and
> > libraries, grrr)
> > What is the best way to post this?  I don't see any file attachments
> > on groups.
>
> > Cheers, Gary
>
> > On Mar 2, 8:23 am, Eli Jones <eli.jo...@gmail.com> wrote:
> >> Are these threads you're using (at this point, it really seems like you
> >> should post some simplified code to illustrate the issue at hand) waiting
> >> for their response before trying to get again?
>
> >> Posting some code to help recreate this issue will lead to a much faster
> >> resolution.. as it stands.. I just know that someone on the internet has
> >> "10
> >> threads" that are hitting a dynamic request limit.
>
> >> I also know that in the initial e-mail, when the request took longer to
> >> return.. these "threads" were hitting a lower dynamic request limit (only
> >> 4
> >> could run).  This suggest that there is an important detail to how your
> >> "threads" are doing their work.. and we would need that to provide useful
> >> help.
>
> >> Thanks for info.
>
> >> On Tue, Mar 2, 2010 at 10:01 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?
>
> ...
>
> read more »

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