On Sat, 2003-08-16 at 03:50, Barlow, Dustin wrote: > Adrian Brock wrote: > > >The order of work is roughly: > > > >1) receive() > >2) getSession() and enlist in tx > >3) getMDB() > >4) onMessage() > >5) releaseMDB() > >6) commitSession() > > Why couldn't the commitSession() be done prior to releaseMDB()? Seems that > if 5 and 6 were flipped, the overall behaviour would be the same. Plus with > a singleton MDB setup, one could take advantage of the read-ahead > optimization by having MaxSize set to a value higher then one, and still > have acidity of CMT between each MDB invocation of onMessage(). > > Otherwise, you basically have to choke off the pooling at the session level > to keep the async behaviour of the MDB at bay until the session commits. > > Is it done that way because another transactable resource could be enlisted > for which the session would have to commit after releaseMDB()? Even if the > MDB itself calls a CMT SSB, the releaseMDB() would be presumably done after > the releaseSSB(). >
No it is done that way for two reasons: 1) Symmetry - JMS doesn't care that when it invokes onMessage on the MDB container that it actually gets delivered to a pooled EJB underneath. The MDB either runs in the transactional context or suspends it (Requred or NotSupported) it never controls the transaction (RequiresNew) 2) There is a <MaxMessages> setting that allows you to process multiple messages in the same transaction/session. It would be a mistake for one of the MDB onMessages to commit the session when it still has messages to process. Regards, Adrian > IE: > > 1) receive() > 2) getSession() and enlist in tx > 3) getMDB() > 4) onMessage() > 5) invoke CMT method on SSB() > 5) getSSB() and enlist in tx > 6) run CMT method > 7) releaseSSB() > 8) releaseMDB() > 9) commitSession() > > Dustin > > > ------------------------------------------------------- > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > Data Reports, E-commerce, Portals, and Forums are available now. > Download today and enter to win an XBOX or Visual Studio .NET. > http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 > _______________________________________________ > JBoss-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/jboss-user ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
