Set timer persistence to db in domain.xml: <timer-service thread-pool-name= " default " default -data-store= " default -db-store" > <data-stores> <database-data-store name= " default -db-store" datasource-jndi-name= "java:jboss/datasources/timerDS" database= "oracle" partition= " default " /> </data-stores> </timer-service> Create a simple timer: @Schedule(hour= "*" , minute= "*" , second= "*/10" ) public void testTimer() { logger.warn( "Test timer executed at {}" , System .currentTimeMillis()); } Either: Start the application on a cluster with more than one running node. or Start only one node of the cluster. Start the application. You should see the timer running in the logs. Open a session to the database from a db client (i.e. sqlplus) Between two timer executions, set the connection to serializable and update the timer's row in the database: SET transaction ISOLATION level serializable; UPDATE JBOSS_EJB_TIMER SET NEXT_DATE = '16-MÁRC. -18 23.30.00,000000000' , PREVIOUS_RUN = '16-MÁRC. -18 23.30.00,000000000' , TIMER_STATE = 'ACTIVE' WHERE TIMED_OBJECT_ID= 'app-1.0.0-SNAPSHOT.app-1.0.0-SNAPSHOT.TimerService' AND ID = 'db266f25-883a-44ec-845f-4e45fe727a3a' AND PARTITION_NAME = ' default ' ; Until the transaction is commited, the server does not log any more execution since the server's connection is blocked until commit. After the transaction in sqlplus is commited the server throws a jdbcException with root cause ORA-08177: can't serialize access for this transaction Test results: [Server:server-one] 16:05:10,008 WARN [hu.eeszt.batch.UtemezoService] (EJB default - 2) Test timer executed at 1458572710008 [Server:server-one] 16:05:20,009 WARN [hu.eeszt.batch.UtemezoService] (EJB default - 7) Test timer executed at 1458572720009 [Server:server-one] 16:05:30,008 WARN [hu.eeszt.batch.UtemezoService] (EJB default - 4) Test timer executed at 1458572730008 [Server:server-one] 16:05:42,792 ERROR [org.jboss.as.ejb3] (EJB default - 8) WFLYEJB0164: Exception running timer task for timer [id=db266f25-883a-44ec-845f-4e45fe727a3a timedObjectId=jelenteskezelo-1.0.0-SNAPSHOT.jelenteskezelo-1.0.0-SNAPSHOT.UtemezoService auto-timer?:true persistent?:true timerService=org.jboss.as.ejb3.timerservice.TimerServiceImpl@5ae465ae initialExpiration=null intervalDuration(in milli sec)=0 nextExpiration=Mon Mar 21 16:05:40 CET 2016 timerState=ACTIVE info=null] on EJB jelenteskezelo-1.0.0-SNAPSHOT.jelenteskezelo-1.0.0-SNAPSHOT.UtemezoService: java.lang.RuntimeException: java.sql.SQLException: ORA-08177: can't serialize access for this transaction [Server:server-one] [Server:server-one] at org.jboss.as.ejb3.timerservice.persistence.database.DatabaseTimerPersistence.shouldRun(DatabaseTimerPersistence.java:421) [Server:server-one] at org.jboss.as.ejb3.timerservice.TimerServiceImpl.shouldRun(TimerServiceImpl.java:1117) [Server:server-one] at org.jboss.as.ejb3.timerservice.TimerTask.run(TimerTask.java:124) [Server:server-one] at org.jboss.as.ejb3.timerservice.TimerServiceImpl$Task$1.run(TimerServiceImpl.java:1221) [Server:server-one] at org.wildfly.extension.requestcontroller.RequestController$QueuedTask$1.run(RequestController.java:497) [Server:server-one] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [Server:server-one] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [Server:server-one] at java.lang.Thread.run(Thread.java:745) [Server:server-one] at org.jboss.threads.JBossThread.run(JBossThread.java:320) [Server:server-one] Caused by: java.sql.SQLException: ORA-08177: can't serialize access for this transaction [Server:server-one] [Server:server-one] at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:447) [Server:server-one] at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396) [Server:server-one] at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:951) [Server:server-one] at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:513) [Server:server-one] at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:227) [Server:server-one] at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531) [Server:server-one] at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:208) [Server:server-one] at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:1046) [Server:server-one] at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1336) [Server:server-one] at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3613) [Server:server-one] at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:3694) [Server:server-one] at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeUpdate(OraclePreparedStatementWrapper.java:1354) [Server:server-one] at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:537) [Server:server-one] at org.jboss.as.ejb3.timerservice.persistence.database.DatabaseTimerPersistence.shouldRun(DatabaseTimerPersistence.java:410) [Server:server-one] ... 8 more [Server:server-one]