Re: [Springframework-developer] Race condition with transaction synchronization?

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Hello,

Sorry to respond to my own post, but if there's someone out there that 
is familiar with SessionFactoryUtils, I would appreciate a little of 
your time to discuss this issue. This appears to be a bug in the JTA 
session synchronization code for hibernate.

Thanks,
Dave

Dave Ballard wrote:

> Hello,
>
> I posted this on the forums, but costin and Rod suggested that I post 
> it here.
>
> I'm using Spring Framework 1.1.5 with Hibernate on WebLogic Server 
> 6.1. I'm testing timeout scenarios, and I've run into an issue I need 
> some help with. I'm slowly eliminating EJB's from my application, but 
> I do have some legacy EJB code to deal with. In my scenario, my 
> servlet is calling a SLSB, which in turn calls spring-managed 
> transactional services. These transaction service join the CMT 
> transaction created by the EJB container. I have:
>
> Code:
>
> 1) A servlet calls SLSB with CMT.
> 2) The SLSB calls SessionFactoryUtils.getSession(sessionFactory, true)
> -- This binds the hibernate session to the current thread
> 3) The SLSB calls a spring-managed transactional service
> -- This bean uses the bound session as expected
> 4) The SLSB calls another spring-managed transactional service
> -- This bean uses the bound session as expected
> 5) The SLSB exits
> -- The TransactionSynchronizationManager unbinds the bound session as 
> expected
>
>
> So the non-timeout scenario functions as expected. Now I introduce a 
> timeout (by causing blocking in by database) prior to (3). With the 
> timeout scenario, I encounter one of two results:
>
> Code:
>
> A) A spring HibernateJdbcException wrapping a weblogic 
> TimedOutException as expected.
> B) An IllegalStateException Already value 
> [org.springframework.orm.hibernate.SessionHolder@6f2304] for key 
> [net.sf.hibernate.impl.SessionFactoryImpl@655ad0] bound to thread 
> [ExecuteThread: '29' for queue: 'default']
>
>
> Whether I get (A) or (B) is seemingly random. I've created a 
> diagnostic version of SessionFactoryUtils to see what is happening in 
> more detail.
> In scenario (B), it looks like WebLogic's transaction manager is 
> grabbing another thread from the pool and is invoking spring's 
> JtaSessionSynchronization.afterCompletion() which is resulting in 
> doClose() being called. I've added a dumpStack() in doClose(), and 
> here is what I see. The line numbers will be a little off because of 
> my diagnostic code:
>
> Code:
>
> java.lang.Exception: Stack trace
>        at java.lang.Thread.dumpStack(Thread.java:992)
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.doClose(SessionFactoryUtils.java:738) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.closeSessionOrRegisterDeferredClose(SessionFactoryUtils.java:726) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.access$300(SessionFactoryUtils.java:89) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils$SpringSessionSynchronization.beforeCompletion(SessionFactoryUtils.java:867) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils$JtaSessionSynchronization.afterCompletion(SessionFactoryUtils.java:978) 
>
>        at 
> weblogic.transaction.internal.ServerSCInfo.callAfterCompletions(ServerSCInfo.java:464) 
>
>        at 
> weblogic.transaction.internal.ServerTransactionImpl.callAfterCompletions(ServerTransactionImpl.java:2139) 
>
>        at 
> weblogic.transaction.internal.ServerTransactionImpl.setRolledBack(ServerTransactionImpl.java:2090) 
>
>        at 
> weblogic.transaction.internal.ServerTransactionImpl.globalRetryRollback(ServerTransactionImpl.java:2188)DEBUG 
> 18:19:23,000 [ExecuteThread: '34' for queue: 'default'] [edemo_acme] 
> (Transacti
>        at 
> weblogic.transaction.internal.ServerTransactionImpl.globalRollback(ServerTransactionImpl.java:2080) 
>
>        at 
> weblogic.transaction.internal.TransactionImpl$1.execute(TransactionImpl.java:1617) 
>
>        at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:159)
>        at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:140)
>
>
> Meanwhile, the original timeout thread, who is in the middle of 
> calling getSession(), and hasn't yet encountered the weblogic 
> TimedOutException,
> tries to bind the session holder to the thread, and fails:
>
> Code:
>
> ERROR 18:19:23,046 [ExecuteThread: '34' for queue: 'default'] 
> [edemo_acme] (TransactionAspectSupport.java:264) - Application 
> exception overridden by rollback exception
> java.lang.IllegalStateException: Already value 
> [org.springframework.orm.hibernate.SessionHolder@747db9] for key 
> [net.sf.hibernate.impl.SessionFactoryImpl@606e55] bound to thread 
> [ExecuteThread: '34' for queue: 'default']
>        at 
> org.springframework.transaction.support.TransactionSynchronizationManager.bindResource(TransactionSynchronizationManager.java:147) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.getSession(SessionFactoryUtils.java:346) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.getSession(SessionFactoryUtils.java:266) 
>
>        at 
> org.springframework.orm.hibernate.SessionFactoryUtils.getSession(SessionFactoryUtils.java:223) 
>
>        at 
> org.springframework.orm.hibernate.HibernateInterceptor.invoke(HibernateInterceptor.java:149) 
>
>        at 
> org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144) 
>
>        at 
> org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:174) 
>
>        at $Proxy93.findContract(Unknown Source)
>        at 
> mycode.ContractServiceImpl.findContract(ContractServiceImpl.java:59)
>        ...
>
>
> It's not clear to me who the culprit is here, not being that familiar 
> with JTA and Spring. Perhaps the beforeCompletion() called by the 
> weblogic transaction manager is not cleaning up properly? Any ideas?
>
> Thanks for your help,
> Dave
>
>
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