We are setting up a clustered JBoss environment. HA JMS is not an option for us. Each JBoss instance has unique queue names. The two JBoss iinstances are using one Oracle database. When we place a certain amount of load on the systems (like 6-8 msgs/sec) with the two JBoss vms writing to the same database tables we can produce this error: Thoughts? Using JBoss 4.0.4.GA TP-Processor33] TransactionImpl.logXAException 2007-06-08 08:24:16,436 WARN XAException: tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=ngtest1.f4tech.com/78237, BranchQual=, localId=78237] errorCode=XAER_RMERR org.jboss.mq.SpyXAException: - nested throwable: (org.jboss.mq.SpyTransactionRolledBackException: Transaction was rolled back.; - nested throwable: (org.jboss.mq.SpyJM SException: Could not create tx: 26635; - nested throwable: (java.sql.SQLException: ORA-00001: unique constraint (NGTEST.PK_JMS_TRANSACTIONS) violated ))) at org.jboss.mq.SpyXAResource.prepare(SpyXAResource.java:149) at org.jboss.tm.TransactionImpl$Resource.prepare(TransactionImpl.java:2212) at org.jboss.tm.TransactionImpl.prepareResources(TransactionImpl.java:1660) at org.jboss.tm.TransactionImpl.commit(TransactionImpl.java:347) at org.jboss.tm.TxManager.commit(TxManager.java:240) at Thanks in advance. Franz View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4052671#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...