cocoon-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Giacomo Pati <giac...@apache.org>
Subject Re: Strange problems with concurrent access of Xalan-2.0.0
Date Thu, 15 Feb 2001 22:16:04 GMT
Berin Loritsch wrote:
> Giacomo Pati wrote:
> > Carsten Ziegeler wrote:
> > > Hello,
> > >
> > > since the switch from the Xalan2D07 to the Xalan-2.0.0 version in
> > > Cocoon2 we get sometimes very strange problems.
> > >
> > > We are using frames which all four use the same stylesheets. The xalan
> > > is driven by the cocoon pipeline.
> > >
> > > If we turn on the storing (formerly known as caching) of the
> > > TraxTransformer we get from time to time a NPE in one frame. Sometimes
> > > its even worse: One frame contains part of the content of another frame
> > > and the other frame is totally broken. Reloading the whole page brings
> > > up all frames correctly.
> > >
> > > However if we turn off the storing we never did see this phenomenen. So
> > > we assume that this problems have something to do with the storing.
> > >
> > > The store stores the Templates. Is it possible, that this problem can
> > > occure, when several threads use the same Template (as delivered by the
> > > store). A thread might finish first, resetting the template and the
> > > other thread still try to use it.
> >
> > A Template IIRC should be thread safe but the actual transformation is
> > done by a Transformer object which can be obtained from the Template (or
> > is it the other way around?).
> >
> > Wait a second I'll try to do a stress test using ab....
> >
> >     ab -c 20 -n 200 http://localhost:8080/cocoon/welcome
> >
> > No, I can't reproduce the failure. All runs well here.
> >
> > Any guesses from the Xalan Team?
> >
> > Giacomo
>
> I ran accross this abnormality when I stress tested Cocoon using
> Apache JRun.  Please note, that I had to have the requests comming
> _very_ quickly to to actually get it to show up.

What is Apache JRun? The ab command I've use above uses 20 concurrent threads 
pounding a total of 200 requests on to a Tomcat 3.2.1 and the latest C2. Did 
you add more concurrent requests?

Giacomo

>
> > > This is only a guess - has someone else had these problems?
> > >
> > > As they only occur occasionally it his very hard to reproduce them...
> > >
> > > Perhaps someone of you has a guess whats going on.
> > >
> > > The exception we get is the following:
> > >
> > > java.lang.NullPointerException
> > >         at
> > > org.apache.xalan.templates.ElemCopy.execute(ElemCopy.java:145) at
> > > org.apache.xalan.templates.ElemForEach.transformSelectedNodes(ElemFor
> > > Each.java:495)
> > >         at
> > > org.apache.xalan.templates.ElemApplyTemplates.execute(ElemApplyTempla
> > > tes.java:193)
> > >         at
> > > org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Tr
> > > ansformerImpl.java:2154)
> > >         at
> > > org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Tr
> > > ansformerImpl.java:2097)
> > >         at
> > > org.apache.xalan.transformer.TransformerImpl.applyTemplateToNode(Tran
> > > sformerImpl.java:2029)
> > >         at
> > > org.apache.xalan.transformer.TransformerImpl.transformNode(Transforme
> > > rImpl.java:1189)
> > >         at
> > > org.apache.xalan.transformer.TransformerImpl.run(TransformerImpl.java
> > >
> > > :2894)
> > >
> > > This indicates that the ResultTreeHandler is not available (set to
> > > null).
> > >
> > > As most times everything is working fine it must have to do with the
> > > parallel usage of the stylesheets.
> > >
> > >
> > >
> > > Carsten Ziegeler
> > >
> > > Open Source Group              sunShine - Lighting up e:Business
> > > ================================================================
> > > Carsten Ziegeler, S&N AG, Klingenderstrasse 5, D-33100 Paderborn
> > > www.sundn.de                           mailto:cziegeler@sundn.de
> > > ================================================================
> > >
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: cocoon-dev-unsubscribe@xml.apache.org
> > > For additional commands, email: cocoon-dev-help@xml.apache.org
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: cocoon-dev-unsubscribe@xml.apache.org
> > For additional commands, email: cocoon-dev-help@xml.apache.org
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: cocoon-dev-unsubscribe@xml.apache.org
> For additional commands, email: cocoon-dev-help@xml.apache.org

Mime
View raw message