I ran into this same problem a while ago, and I suggested the same (at least the thread, that holds the lock, should not be locked out). Somebody wrote a 'SimpleReadWriteEJBLock' class, that seems to achieve exactly this, but I could not find any info related to it.
You can also try to play around with the method attribute read-only setting in jboss.xml (see the DTD). To get better concurrency you may consider switching to the Instance Per Transaction configuration (see standardjboss.xml) . The QueuedPessimisticEJBLock does not make any sense with CMP, IMHO (if you use it, it turns JBoss into a single tasking system). Georg -----Original Message----- From: [EMAIL PROTECTED] [mailto:jboss-user-admin@;lists.sourceforge.net] On Behalf Of Jim Crossley Sent: Thursday, October 24, 2002 22:06 To: [EMAIL PROTECTED] Subject: Re: [JBoss-user] Erroneous deadlock detected??? Well, it would seem to me that a ThreadLocal instance could help solve this problem. If one thread tries to acquire a lock it already owns, it ought to get it, right? If we were to apply the same semantics you describe to a simple Java class, then calling setX would always block... class C { synchronized void setX() { setY(); } synchronized void setY() { ; } } If this is really the way JBoss works, and nobody knows a good reason why it should, can someone point me to the package/class responsible for this behavior and I'll take a whack at fixing it? Thanks, Jim On Thu, 2002-10-24 at 15:40, Michael Bartmann wrote: > Explanation attempt inline. > > Regards, > Michael Bartmann > > Jim Crossley wrote: > > I have an MDB with the following pseudocode in its onMessage method: > > > > public void onMessage(Message msg) > > { > > // Entity bean = home.create(...) > > // bean.setX(...) > this starts a tx1 and locks the instance bean. > > // bean.setY(...) > this suspends the tx1 on bean temporarily, > and starts a tx2, which tries to obtain the lock on the bean, which it > will never get, because tx1 is not commited or rollbacked yet. > We had this problem under 2.4.4 w/o deadlock detection. Problem: > even the tx timeout didn't work in this case; the server locked forever... :-( > > } > > > > Each of the three methods, create, setX, and setY have a > > trans-attribute of "RequiresNew". With only one client posting a > > message, a "deadlock detected" exception is thrown when setX is > > invoked. How can deadlock occur when only one thread is active > > > > Thanks, > > Jim > > > > > > > > > > ------------------------------------------------------- > > This sf.net email is sponsored by: Influence the future > > of Java(TM) technology. Join the Java Community > > Process(SM) (JCP(SM)) program now. > > http://ad.doubleclick.net/clk;4729346;7592162;s?http://www.sun.com/javav ote > > _______________________________________________ > > JBoss-user mailing list > > [EMAIL PROTECTED] > > https://lists.sourceforge.net/lists/listinfo/jboss-user > > > > > > ------------------------------------------------------- > This sf.net email is sponsored by: Influence the future > of Java(TM) technology. Join the Java Community > Process(SM) (JCP(SM)) program now. > http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0003en > _______________________________________________ > JBoss-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/jboss-user ------------------------------------------------------- This sf.net email is sponsored by: Influence the future of Java(TM) technology. Join the Java Community Process(SM) (JCP(SM)) program now. http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0003en _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user ------------------------------------------------------- This sf.net email is sponsored by: Influence the future of Java(TM) technology. Join the Java Community Process(SM) (JCP(SM)) program now. http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0004en _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
