Java Mailing List Archive

http://www.junlu.com/

Home » Home (12/2007) » Apache Tomcat »

Re: Multi processor issue

Leon Rosenberg

2006-12-08

Replies:

On 12/8/06, Caldarale, Charles R <Chuck.Caldarale@(protected):
> > From: Marziou, Gael [mailto:gael.marziou@(protected)]
> > Subject: RE: Multi processor issue
> >
> > Tomcat does not synchronize before locking the map but that should not
> > be an issue because the request is guaranteed to be processed by only
> > one thread.
>
> But the evidence seems to show two threads are manipulating the same
> request, otherwise you wouldn't get the error on the ParameterMap. Does
> a full thread dump show any threads that aren't part of the set started
> by Tomcat?

either that, or a Request is reused before recycle() has been executed
completely.
I fear we have to know what your software on top does exactly :-)

Alas, you could do a test and check whether the method getParameter is
actually ever called by two threads during one lifecycle (patching the
ParameterMap class, storing last accessing thread, and checking
whether another thread is already stored on access)

Theoretically Cael is right with the above, but only theoretically,
since we don't know how thread safe Gael's "ontop" application is, and
even than, it wouldn't be the first synchronization issue we found in
tomcat.
And Gael, the CPU is the most valuable resource in the production
environment, are you really ready to give up your scaleability but
simply not investigating further?

Leon

>
> - Chuck
>
>
> THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY
> MATERIAL and is thus for use only by the intended recipient. If you
> received this in error, please contact the sender and delete the e-mail
> and its attachments from all computers.
>
> ---------------------------------------------------------------------
> To start a new topic, e-mail: users@(protected)
> To unsubscribe, e-mail: users-unsubscribe@(protected)
> For additional commands, e-mail: users-help@(protected)
>
>

---------------------------------------------------------------------
To start a new topic, e-mail: users@(protected)
To unsubscribe, e-mail: users-unsubscribe@(protected)
For additional commands, e-mail: users-help@(protected)

©2008 junlu.com - Jax Systems, LLC, U.S.A.