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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 Fri, 22 Jun 2012 08:21:13 GMT
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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