FYI there might be an issue with message selectors and jms priorities. An
engineer here is looking into it further. I will let you know what he finds
out.
--jason
On Fri, 17 Aug 2001, Hiram Chirino wrote:
> The whole MDB being designed as a push is that a push puts less strain on
> the JMS provider. Messages can flow the the MDB with out the MDB having to
> poll the server for messages.
>
> Regards,
> Hiram
>
> >From: Jason Dillon <[EMAIL PROTECTED]>
> >Reply-To: [EMAIL PROTECTED]
> >To: <[EMAIL PROTECTED]>
> >Subject: Re: [JBoss-dev] Improving MDB behavior in the presence of delivery
> >failures
> >Date: Fri, 17 Aug 2001 12:24:43 -0700 (PDT)
> >
> >MDB is not really a good solution for stuff like this. MDB is basically a
> >push from the provider to a bean with out any insight as to the state of
> >the
> >application short of the available server sessions.
> >
> >A better approache would be a pull from the provider from the application
> >layer which would simply hand off the message to a session bean which
> >implementes MessageListener.
> >
> >The pulling thread could then use application specific logic to determine
> >if
> >it should pull off a message.
> >
> >I like the idea of a reject queue or something like that for MDB though.
> >
> >--jason
> >
> >
> >On Thu, 16 Aug 2001, Scott M Stark wrote:
> >
> > > The mdb does not have to thrown an exception to cause this behavior. If
> >it
> > > interacts with another ejb that is transacted and that bean rolls the
> > > transaction
> > > back the msg will get redeliverd. I have a trivally test case that
> >causes
> > > the problem:
> > >
> > > public void onMessage(Message m)
> > > {
> > > try
> > > {
> > > IHome home = ...;
> > > home.findByPrimaryKey(null);
> > > }
> > > catch(Throwable t)
> > > {
> > > }
> > > }
> > >
> > > The tx will be rolled back by the failed findByPrimaryKey() call which
> >will
> > > cause the msg
> > > to be redelivered and were spinning.
> > >
> > > ----- Original Message -----
> > > From: "Hiram Chirino" <[EMAIL PROTECTED]>
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Thursday, August 16, 2001 6:28 PM
> > > Subject: Re: [JBoss-dev] Improving MDB behavior in the presence of
> >delivery
> > > failures
> > >
> > >
> > > >
> > > > Per spec the MDB should not be throwing any exceptions.. This would
> >mean
> > > > that it's thier responsibility to put the message to a 'rejected'
> >queue.
> > > >
> > > > But I think that is the best solution would be to allow the MDB to be
> > > > configured with the 'rejected' queue in it's deployment descriptor. I
> > > know
> > > > that not everybody will enclose thier MDB code in try { } catch
> >(Throable
> > > e)
> > > > {}
> > > >
> > > >
> > > > Regards,
> > > > Hiarm
> > > >
> > > > >From: "Scott M Stark" <[EMAIL PROTECTED]>
> > > > >Reply-To: [EMAIL PROTECTED]
> > > > >To: <[EMAIL PROTECTED]>
> > > > >Subject: [JBoss-dev] Improving MDB behavior in the presence of
> >delivery
> > > > >failures
> > > > >Date: Thu, 16 Aug 2001 18:22:23 -0700
> > > > >
> > > > >Right now there are any number of ways to cause JBoss to spin in a
> >tight
> > > > >loop
> > > > >trying to deliver a transacted msg to an mdb due to a problem with
> >either
> > > > >the msg or mdb code that either causes an exception thrown from
> > > onMessage()
> > > > >or the tx to be rolled back. A trivial example of the latter is to
> >have
> > > an
> > > > >mdb
> > > > >do a findByPrimaryKey() using a key from the msg that happens to be
> >null.
> > > > >
> > > > >One solution would be to have the mdb container fail such msgs after
> >so
> > > > >many delivery attempts. On failure, the msg along with the exception
> > > would
> > > > >be placed into a error queue associated with the container. An admin
> > > would
> > > > >have to pull the msg off, fix any data problems and then place the
> >msg
> > > > >back onto the mdb queue/topic for redelivery.
> > > > >
> > > > >Are there any better ways to handle this?
> > > > >
> > > > >
> > > > >
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