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From vicky b <vickyb2...@gmail.com>
Subject Re: Tomcat Concurrency
Date Wed, 17 Jul 2013 05:39:07 GMT
HI All,

 Just out of curiosity can you please let me know if there are 10 clients
who access 10 different browsers and make request at the same time what is
the expected output


On Tue, Jul 16, 2013 at 10:14 PM, Christopher Schultz <
chris@christopherschultz.net> wrote:

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> Konstantin,
>
> On 7/15/13 6:38 PM, Konstantin Kolinko wrote:
> > 2013/7/16 Mark Haroldson <MarkHaroldson@msn.com>:
> >> Hello;
> >>
> >>
> >>
> >> I am running a tomcat 6 webapp using Jersey and I am running into
> >> a concurrency issue. When there are multiple concurrent
> >> connections to tomcat only one or two are processed concurrently.
> >> I have increased the maxThreads on the connector and now can see
> >> the requests being processed  by different threads however I
> >> still on observe one or two threads running concurrently.
> >>
> >>
> >>
> >> Example:
> >>
> >> Given the following servlet;
> >>
> >>
> >>
> >> Servlet()
> >>
> >> {
> >>
> >> Output("Start thread");
> >>
> >> Thread.sleep(20000);
> >>
> >> Output("End thread")
> >>
> >> }
> >>
> >>
> >>
> >> I would expect the following output
> >>
> >>
> >>
> >> Start Thread
> >>
> >> Start Thread
> >>
> >> Start Thread
> >>
> >> Start Thread
> >>
> >> End Thread
> >>
> >> End Thread
> >>
> >> End Thread
> >>
> >> End Thread
> >>
> >>
> >>
> >> Instead I see
> >>
> >> Start Thread
> >>
> >> Start Thread
> >>
> >> End Thread
> >>
> >> End Thread
> >>
> >> Start Thread
> >>
> >> End Thread
> >>
> >> Start Thread
> >>
> >> End Thread
> >>
> >>
> >>
> >> What are the factors that control thread concurrency in Tomcat?
> >> Has anyone seen behavior like this before? Should I expect a high
> >> number of concurrent threads or does java/tomcat gate access to
> >> the servlet?
> >>
> >
> > Looking at a crystal ball I would guess that your client is a web
> > browser. A well-behaving browser creates no more than 2
> > simultaneous connections to the same host (a limitation recommended
> > by the HTTP specification).
>
> No longer true. Firefox and Chrome default to 6 per server:
> http://kb.mozillazine.org/Network.http.max-connections-per-server
> http://code.google.com/p/chromium/issues/detail?id=12066
>
> > A Tomcat can certainly serve more than 2 clients simultaneously. It
> > is possible to mis-configure it or create a servlet that serves no
> > more than 1 client, but you must be creative (in a newbie way) to
> > do so.
> >
> > Without seeing your actual configuration and your actual code it
> > is impossible to provide any review.
> >
> > If congestion were at Tomcat side, as when several threads are
> > waiting for the same resource, it would be easy to spot the place
> > by taking a pair of thread dumps (see wiki -> FAQ ->
> > Troubleshooting).
>
> Mark, you should probably print the thread id when doing your
> printlns. That will help you see what is going on. Also, you might
> want to try making more than 4 connections. What client are you using?
>
> - -chris
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> =Punl
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-- 
*Thanks & Regards
 Vickyb

*

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