[ http://jira.jboss.com/jira/browse/JBPM-1072?page=comments#action_12392824 ] Alexey Kostylev commented on JBPM-1072: --------------------------------------- As I investigate this issue I find that the problem with running several JobExecutor instances on the same machine is in query condition: where ( (job.lockOwner is null) or (job.lockOwner = :lockOwner) ) So 'lockOwner' is the same for all instances on the same machine, so every instance capture jobs that are executing on other instances at that time. So then I tried to run two instances of Job Executor on different machines. And there's second problem. The result of query 'JobSession.getFirstAcquirableJob' is always returned from the method acquireJobs() not depending on if optimistic locking is failed or not. Here is the log: ... 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG JobExecutorThread : querying for acquirable job... 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG JobExecutorThread : trying to obtain a lock for 'job[444795]' 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG JbpmContext : closing jbpmContext org.jbpm.JbpmContext@274874 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG Services : closing service 'persistence': org.jbpm.persistence.db.DbPersistenceService@116ce6e 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG DbPersistenceService : committing hibernate transaction org.hibernate.transaction.JDBCTransaction@105f759 12:09:42,687 [JbpmJobExector:192.168.125.34:1] INFO DbPersistenceService : optimistic locking failed 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG DbPersistenceService : rolling back hibernate transaction 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG DbPersistenceService : closing hibernate session 12:09:42,687 [JbpmJobExector:192.168.125.34:1] INFO Services : problem closing service 'persistence': optimistic locking failed 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG Services : closing service 'tx': org.jbpm.tx.TxService@4aa085 12:09:42,687 [JbpmJobExector:192.168.125.34:1] DEBUG JobExecutorThread : obtained locks on following jobs: [job[444795]] ... I looked in the code and saw there confirmation of this behaviour. Should I create the separate issue for second problem, what do you think? -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira