Timer service won't work reliably...

[tsar_bomba]

I've been working w/ some examples in the new Enterprise JavaBeans 3.0 book and I created a simple timer to run every 10 minutes and check for data integrity.

When JBoss decides to let it run, it works great. However it doesn't always work when I deploy the app....sometimes I get this exception:

11:45:20,480 ERROR [TimerServiceImpl] Cannot create txtimer
java.lang.IllegalStateException: Unable to persist timer
 at org.jboss.ejb.txtimer.DatabasePersistencePolicy.insertTimer(DatabasePersistencePolicy.java:126)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
 at $Proxy22.insertTimer(Unknown Source)
 at org.jboss.ejb.txtimer.TimerServiceImpl.createTimer(TimerServiceImpl.java:256)
 at org.jboss.ejb.txtimer.TimerServiceImpl.createTimer(TimerServiceImpl.java:202)
 at com.agribeef.abcommerce.service.PollingServiceBean.init(PollingServiceBean.java:32)

My timer looks like this:

@Stateless
public class PollingServiceBean implements PollingService
{
 @Resource
 private TimerService ts;

 private static final int timeout = 1000 * 60 * 10; //ten minutes

 public PollingServiceBean()
 {
 }

 public void init()
 {
 if (ts.getTimers().size() == 0)
 {
 this.ts.createTimer(5000, timeout, "pollServicesTimer");
 }
 }

 @Timeout
 public void startService(Timer timer)
 {
 try
 {
 //do something here....
 }
 catch (Exception exp)
 {
 // TODO Auto-generated catch block
 exp.printStackTrace();
 }
 }
}

First of all, what is "txtimer", I haven't named my timer that?

It runs sometimes and runs well...and then I re-deploy the same code and get the exception above...am I doing something wrong or is there a known problem?

Thanks!

[tsar_bomba]

I'm sorry, I realize I just missed probably the most important part of the exception, the root cause!

It looks like HSQLDB doesn't like that I'm trying to start a timer w/ the same name.

Caused by: java.sql.SQLException: Unique constraint violation: in statement [insert into TIMERS (TIMERID,TARGETID,INITIALDATE,TIMERINTERVAL,INSTANCEPK,INFO) values (?,?,?,?,?,?)]
 at org.hsqldb.jdbc.Util.throwError(Unknown Source)
 at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source)
 at org.jboss.resource.adapter.jdbc.CachedPreparedStatement.executeUpdate(CachedPreparedStatement.java:95)
 at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:251)
 at org.jboss.ejb.txtimer.GeneralPurposeDatabasePersistencePlugin.insertTimer(GeneralPurposeDatabasePersistencePlugin.java:186)
 at org.jboss.ejb.txtimer.DatabasePersistencePolicy.insertTimer(DatabasePersistencePolicy.java:122)
 ... 138 more

This seems strange to me, I can't redeploy my app or new timers will be inserted w/ the same names...and my timers will blow up!

The book mentions nothing about deleting them or anything of that nature - what can I do?

[tsar_bomba]

So I narrowed this down to a single scenario...it's still not sufficient for me in production and I'm hoping there's at *least* a work-around.

If I restart JBoss the Timer Service crashes w/ the aforementioned exception...however if I re-deploy the app the timer starts - so far on every test.

What can I do?

I put a file named "jboss.xml" in my ejb project's META-INF folder that looks like this but I'm not even sure I've done that much right:

<?xml version="1.0" encoding="UTF-8"?>
<jboss>
 <timer-persistence>false</timer-persistence>
</jboss>

Any help would be greatly appreciated, thanks!