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From Laurent Petit <lpe...@yseop.com>
Subject Re: Re : Re: Issue with keep-alive connections, when using APR Connector on Windows and starting Processes from Servlets
Date Mon, 25 Jun 2012 09:40:34 GMT
Hello, 

Is there anything I can do to help qualify the problem even more ?

Beyond having shown the source code of the servlet, would a fully
mavenized example help? Anything else?

Regards,

-- 
Laurent


On Fri, 2012-06-22 at 10:21 +0200, Laurent Petit wrote:
> Hello,
> 
> On Thu, 2012-06-21 at 22:53 +0200, Jeff MAURY wrote:
> > Is it specific to Wordpad or any launched process will do the trick ?
> > Do you tried with a non UI process (console) ?
> 
> 
> I did an additional test, as you suggested, with a non UI process (a
> small java executable launched in headless mode, whose purpose was just
> to wait for 20 seconds before exiting).
> 
> I can reproduce the problem with this headless executable: the HTTP
> client is blocked until the 20 seconds elapse and the process is killed.
> 
> 
> Here is the modified servlet code I used:
> 
> https://www.refheap.com/paste/3285
> 
> 
> and here is the code for the small java program:
> 
> https://www.refheap.com/paste/3286
> 
> 
> 
> Regards,
> 
> -- 
> Laurent
> 
> 
> 
> > 
> > Jeff
> > 
> > On Thu, Jun 21, 2012 at 10:45 PM, Laurent Petit <lpetit@yseop.com> wrote:
> > 
> > > En Réponse à "Tomcat Users List" <users@tomcat.apache.org> le 21 juin
> > > 2012 00:07 Can you verify your 2 threads (reading input an error) are
> > > launched ? Yes they are. Verified. Can you confirm you are getting the
> > > problem only on Windows ? Yes sir, we're unable to reproduce it on Ubuntu.
> > > Jeff On Wed, Jun 20, 2012 at 4:19 PM, Laurent Petit <lpetit@yseop.com>
> > > wrote: > Hello, > > I have a problem with keep-alive connections,
when
> > > starting a subprocess > (via JDK's default ProcessBuilder/Process API),
> > > while also having > started Tomcat with the APR HTTP/1.1 Connector. >
> The
> > > problem symptom is with Keep-Alive connection, as follows: > > - the
client
> > > (browser, jmeter, etc.) sends a first request > - the servlet starts a
> > > Process for e.g. wordpad.exe > - the servlet returns an acknowledgment html
> > > content, sets the content > length, flushes the writer, and returns >
- the
> > > client displays the received acknowledgement html content, sends > the
> > > second request to the server. > - the server doesn't answer. No Tomcat log
> > > ever reports the start of > something received. > - Then when on the
server
> > > you close the wordpad.exe instance, the server > finally handles the second
> > > request. > > I have created a small servlet code which reproduces the
> > > problem. > For the demo, it suffices to have the started subprocess be >
> > > "wordpad.exe". Of course my real process is more interesting than > that
> > > :-). > > You can find the servlet code for reproducing the test here:
> >
> > > https://www.refheap.com/paste/3254 > > > To reproduce the problem
> > > deterministically, the ConnectionTimeout for > the APR HTTP Connector in
> > > servlet.xml must be set sufficiently low. > With my boxes, I get a 100%
> > > error hit when set at 200 ms. > > You can find here the jmeter script
which
> > > hits the same page again and > again with "keep-alive" option set on: >
>
> > > https://www.refheap.com/paste/3255 > > > So far, the only reliable
> > > solution we have found to work around this > problem is to not use the
> > > HTP/1.1 APR Connector. > > > My configuration : > Windows 2008
US std R2
> > > 64bits > Tomcat 6.0.32 64 bits > Java 6u30 64 bits(Oracle) > >
Same issue
> > > has been observed on Windows 7 32 bits. > > Was not able to reproduce
the
> > > issue on Linux Ubuntu Desktop 11.10 or > 12.04. > > > Thanks for
your
> > > support, ideas, solutions, etc. > > > >
> > > --------------------------------------------------------------------- >
To
> > > unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org > For additional
> > > commands, e-mail: users-help@tomcat.apache.org > > -- Jeff MAURY "Legacy
> > > code" often differs from its suggested alternative by actually working and
> > > scaling. - Bjarne Stroustrup http://www.jeffmaury.com
> > > http://riadiscuss.jeffmaury.com http://www.twitter.com/jeffmaury
> > 
> > 
> > 
> > 
> 

-- 
Laurent Petit

Agence +33 (0)4 78 47 07 49

Email     lpetit@yseop.com

 



 

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