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EJBException: Failed to acquire the pool semaphore
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created by <a href="https://community.jboss.org/people/stannous">Samuel Tannous</a> in <i>JBoss Messaging</i> - <a href="https://community.jboss.org/message/731246#731246">View the full discussion</a>
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<div class="jive-rendered-content"><p>Hi Guys,</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I see that this problem's come up a few times in the past but our scenario is different so I'll raise it again. We're using ActiveMQ in JBoss 6 and are seeing intermittent errors dispatching messages which causes them to be lost (the JMX consolde shows that they've been dequeued but the listener never gets them).</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>There's a good explanation of the "Failed to acquire the pool semaphore" error here: <a class="jive-link-external-small" href="http://stackoverflow.com/questions/7015583/ejbexception-failed-to-acquire-the-pool-semaphore">http://stackoverflow.com/questions/7015583/ejbexception-failed-to-acquire-the-pool-semaphore</a></p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>And it sounds simple enough except we're not using prefetch... so my question is, how can this error occur when messages are being polled instead of batched?</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Our embedded broker url is:</p><p style="padding-left: 30px;">vm://myBroker?create=false&amp;<strong>jms.prefetchPolicy.all=0</strong>&amp;jms.alwaysSyncSend=true</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The ejb3-interceptors-aop.xml MDB config is default (@org.jboss.ejb3.annotation.Pool (value="StrictMaxPool", maxSize=15, timeout=10000))</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The message listener is annotated with:</p><p style="padding-left: 30px;">@MessageDriven(name = "MyListener", messageListenerInterface = javax.jms.MessageListener.class, activationConfig = {</p><p style="padding-left: 30px;">        @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),</p><p style="padding-left: 30px;">        @ActivationConfigProperty(propertyName = "maxSessions", propertyValue = "20"),</p><p style="padding-left: 30px;">        @ActivationConfigProperty(propertyName = "destination", propertyValue = "queue/com.myorg.MyQueue") })</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The stack's attached:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Any help will be greatly appreciated.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Cheers</p><p>Sam</p></div>
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