Brett Cave [http://community.jboss.org/people/brettcave] created the discussion "JBoss cache / concurrent creation event" To view the discussion, visit: http://community.jboss.org/message/564341#564341 -------------------------------------------------------------- We have been having an issue with this for quite some time, and I am battling to understand the cause of the issue, hoping someone could help explain and work a solution for this. While using a web application an exception occassionally occurs: 2010-09-30 14:12:27,901 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/]] (ajp-0.0.0.0-8009-2) Exception while dispatching incoming RPC call com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract com.mycompany.web.common.client.model.rank.RankResponse com.mycompany.web.common.client.rpc.Ranking Service.rank(java.lang.String,int,com.mycompany.web.common.client.model.rank.RankRequestProperties,java.util.Map,java.util.Map,java.util.Map,java.util.Map)' threw an unexpected exception: javax.ejb.EJBTransactionRolledbackException: Transaction rolled back Just prior to that in the log, the following is seen: 2010-09-30 14:12:27,895 WARN  [org.jboss.cache.interceptors.OptimisticTxInterceptor] (ajp-0.0.0.0-8009-2) Caught exception, will now set transaction to roll back org.jboss.cache.optimistic.DataVersioningException: Transaction attempted to create /adonis/org/hibernate/cache/StandardQueryCache/QUERY/sql: select <QUERY DETAILS>; max rows: 2 anew.  It has already been created since this transaction started, by another (possibly remote) transaction. We have a concurrent creation event.         at org.jboss.cache.interceptors.OptimisticValidatorInterceptor.visitOptimisticPrepareCommand(OptimisticValidatorInterceptor.java:116) .... 2010-09-30 14:12:27,897 WARN  [com.arjuna.ats.arjuna.logging.arjLoggerI18N] (ajp-0.0.0.0-8009-2) [com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator_2] TwoPhaseCoordinator.beforeCompletion - failed for com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple@493ee8c1 org.jboss.cache.optimistic.DataVersioningException: Transaction attempted to create /adonis/org/hibernate/cache/StandardQueryCache/QUERY/sql: select <QUERY DETAILS>; max rows: 2 anew.  It has already been created since this transaction started, by another (possibly remote) transaction. We have a concurrent creation event.         at org.jboss.cache.interceptors.OptimisticValidatorInterceptor.visitOptimisticPrepareCommand(OptimisticValidatorInterceptor.java:116) Environment: The application is deployed in an ear with an ejb and war component. The ejb has a persistence unit, which uses an XA jta-datasource and 3 entity jar-files defined (that are deployed independantly) Another application is deployed that the primary application depends on, an EAR with ejb and persistence. The persistence unit references a different XA datasource and references 1 of the 3 jar-files as above. The issue might be caused by having 2 persistence contexts being applied to a single entity, but not entirely sure on this though I have tried adjusting the transaction manger's configuration to allowMultipleLastResources = true (before we switched to XA datasources, this was necessary with tx datasources and this environment), but the error occurs with this enabled or disabled. I am not sure whether this is a jboss cache issue, hibernate or transaction manager issue. how could I avoid this issue? (the exception occurs irregularly, it's difficult to reproduce). -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/564341#564341] Start a new discussion in JBoss Cache at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]