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Re: JBM clients hangs when creating connections/sessions
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created by <a href="http://community.jboss.org/people/danezu">Daniel Dumitrescu</a> in <i>JBoss Messaging</i> - <a href="http://community.jboss.org/message/645664#645664">View the full discussion</a>
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<div class="jive-rendered-content"><p>Hi again</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>After getting again the same situation a, I made a thread dump on the server side to see what is happening, and there were two types of blocked threads:</p><p>- the JBM's get message count:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>"RMI TCP Connection(1910)-172.19.60.78" daemon prio=10 tid=0x00007f83f3aa3800 nid=0x1c12 waiting for monitor entry [0x0000000061f66000..0x0000000061f68b20]</p><p>   java.lang.Thread.State: BLOCKED (on object monitor)</p><p>        at org.jboss.messaging.core.impl.ChannelSupport.getMessageCount(ChannelSupport.java:480)</p><p>        - waiting to lock <0x00007f840e9f3048> (a java.lang.Object)</p><p>        at org.jboss.messaging.core.impl.PagingChannelSupport.getMessageCount(PagingChannelSupport.java:148)</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>- the XA commits made from the remote client:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>WorkManager(2)-33444" daemon prio=10 tid=0x00007f83e85eb800 nid=0x1aa5 waiting for monitor entry [0x000000005f23a000..0x000000005f23bca0]</p><p>   java.lang.Thread.State: BLOCKED (on object monitor)</p><p>        at org.jboss.messaging.core.impl.ChannelSupport$InMemoryCallback.afterCommit(ChannelSupport.java:1025)</p><p>        - waiting to lock <0x00007f840e9f3048> (a java.lang.Object)</p><p>        at org.jboss.messaging.core.impl.tx.Transaction.commit(Transaction.java:228)</p><p>        - locked <0x00007f84383f5cd0> (a org.jboss.messaging.core.impl.tx.Transaction)</p><p>        at org.jboss.jms.server.endpoint.ServerConnectionEndpoint.sendTransaction(ServerConnectionEndpoint.java:517)</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>All of the threads seems to be waiting for the same object lock:  <0x00007f840e9f3048></p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>The blocking threads (like almost 400 of them) lead to unresponsive JMS queue.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>It seems that the getMessageCount and afterCommit are waiting for a lock that tryies to synch the situation inside JBM's table with the memory refs.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Doesn anyone knows where I can find this lock, i.e. the concrete type? The following classes seems to use it: ServerConnectionEndpoint, org.jboss.messaging.core.impl.tx.Transaction, org.jboss.messaging.core.impl.ChannelSupport (->PagingChannelSupport -> MessagingQueue)</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Regards,</p></div>
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