Hi All, When i tried to execute the rule in multi threaded environment, i got the below mentioned Error logs... I just tried to execute the rule flow with 2 thread, always 1 got executed successfully and one fails with the following error log. ERROR LOG: Hibernate: delete from ProcessInstanceInfo where InstanceId=? and OPTLOCK=? Hibernate: delete from ProcessInstanceInfo where InstanceId=? and OPTLOCK=? 2011/07/04 11:20:06.475{UTC} [JDBCExceptionReporter : JDBCExceptionReporter.java: logExceptions: 100] [RMI TCP Connection(6)-10.50.53.32]: WARN: : SQL Error: 60, SQLState: 61000 2011/07/04 11:20:06.475{UTC} [JDBCExceptionReporter : JDBCExceptionReporter.java: logExceptions: 101] [RMI TCP Connection(6)-10.50.53.32]: ERROR: : ORA-00060: deadlock detected while waiting for resource 2011/07/04 11:20:06.475{UTC} [AbstractFlushingEventListener : AbstractFlushingEventListener.java: performExecutions: 324] [RMI TCP Connection(6)-10.50.53.32]: ERROR: : Could not synchronize database state with session org.hibernate.exception.LockAcquisitionException: could not delete: [org.drools.persistence.processinstance.ProcessInstanceInfo#8130] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:112)...... Thanks, Jose. -- View this message in context: http://drools.46999.n3.nabble.com/org-hibernate-exception-LockAcquisition... Sent from the Drools: User forum mailing list archive at Nabble.com.