Re: [eclipselink-users] Communication failure detected when attempting

[Samba <saasira@xxxxxxxxx>]

Chris,
     Thanks a lot for your help.

 

      I could move ahead the problem because your explanation gave me pointers to find the root cause..

      And your clarification about LIMIT support in eclipselink gave me confidence that I can continue with my approach.

 

Regards,

Samba

 

On Tue, Mar 31, 2009 at 1:15 AM, christopher delahunt <christopher.delahunt@xxxxxxxxxx> wrote:

Hello Samba,

I believe the fetch-size query hint has to do with scrollable cursors paging size, and so is not likely to have an effect on regular queries.
Using the setFirstResult and setMaxResults options -
It depends on how your database runs the query and returns results, but I'd recommend using ordering on the query to ensure results are returned in a consistent order. Some database platforms take advantage of pagination filters such as the Oracle platform using rownum to filter setFirstResult and setMaxResults.  If the platform does not
have pagination support, it will use JDBC to filter out the maxrows and jump to the first result in the returned data.

LIMIT is used in the MySQL platform for pagination, which is supported in the nightly EclipseLink (I am not sure when it was added).  So if you are using the MySQL database platform and
set the setFirstResult and setMaxResults values, the generated SQL will use LIMIT to filter results.

Best Regards,
Chris



Samba wrote:

Hi Chris,
  I think this has to do with query optimisation as the query is indeed taking around 10 seconds  to fetch the results when run from an SQL Editor.
    Actually I wanted to limit the results to a single record and that was working fine with in a second but in JPA I think using te eclipselink query hint
  "eclipselink.jdbc.fetch-size"  and setting that to 1 did not help.
   Now I tried using
      query.setFirstResult(0);
    query.setMaxResults(1);
    query.getSingleResult();
 and I got the expected result pretty quickly around 30 ms.
  But I have a doubt whether the above method gives me consistent results in the same way as database LIMIT keyword does!
Can you give some suggestions here?
 Thanks ad Regards,
Samba

   On Mon, Mar 30, 2009 at 6:50 PM, christopher delahunt <christopher.delahunt@xxxxxxxxxx <mailto:christopher.delahunt@xxxxxxxxxx>> wrote:

   Hello Samba,

   The problem is that the session bean method is taking longer than
   the time allowed for the transaction, causing the transaction to
   timeout.  It is an EJB problem, not necessarily JPA, its just that
   JPA is configured to use the connection associated to the
   transaction (JTA) for reads, and so reports the exception before
   the container does. You can either break up the transaction into
   smaller chunks, or increase the timeout value for transactions -
   I'm not that familiar with WebLogic settings so I can't comment on
   how to change the timeout value.
   Best Regards,
   Chris

   Samba wrote:

       Hi I'm using eclipselink 1.0.2 from Jdeveloper 11.1.0.1 and
       MySQL as database.

          I'm running a java client to test the written functionality
       in a Session Bean deployed to weblogic server (default in
       jdeveloper).
            and I'm getting the error
        [code]
                         /Communication failure detected when
       attempting to perform read query outside of a transaction.
       Attempting to retry query.
                            [EL Warning]: 2009.03.28
       22:02:29.140--UnitOfWork(8724084)--Exception
       [EclipseLink-4002] (Eclipse Persistence Services - 1.0.2
       (Build 20081024)):
       org.eclipse.persistence.exceptions.DatabaseException
       Internal Exception: java.sql.SQLException: Transaction
       BEA1-00032CA83BB89E472B1E not active anymore. tx status =
       Rolled back.
       [Reason=weblogic.transaction.internal.TimedOutException:
       Transaction timed out after 31 seconds
       BEA1-00032CA83BB89E472B1E]
       Error Code: 0
       Call: SQLCall(SELECT latitude, longitude, zipcode, city,
       country_code, ip_start, region_code FROM ip_group_city WHERE
       (ip_start <= ?) ORDER BY ip_start DESC)
       Query: ReadAllQuery(com.gamyam.product.geoip.model.IPGroupCity)


       Here is the stacktrace:

         javax.ejb.EJBException: EJB Exception: ; nested exception is:
          Exception [EclipseLink-23009] (Eclipse Persistence Services
       - 1.0.2 (Build 20081024)):
       org.eclipse.persistence.exceptions.TransactionException
       Exception Description: Error marking externally managed
       transaction for rollback
       Internal Exception: java.lang.IllegalStateException: Cannot
       mark the transaction for rollback.
       xid=BEA1-00032CA83BB89E472B1E, status=Rolled back.
       [Reason=weblogic.transaction.internal.TimedOutException:
       Transaction timed out after 31 seconds
       BEA1-00032CA83BB89E472B1E]
          at
       weblogic.ejb.container.internal.RemoteBusinessIntfProxy.unwrapRemoteException(RemoteBusinessIntfProxy.java:105)
          at
       weblogic.ejb.container.internal.RemoteBusinessIntfProxy.invoke(RemoteBusinessIntfProxy.java:87)
          at $Proxy10.fetchLocation(Unknown Source)
          at
       com.gamyam.product.geoip.model.GeoIPServiceClient.main(GeoIPServiceClient.java:60)
       Caused by: Exception [EclipseLink-23009] (Eclipse Persistence
       Services - 1.0.2 (Build 20081024)):
       org.eclipse.persistence.exceptions.TransactionException
       Exception Description: Error marking externally managed
       transaction for rollback
       Internal Exception: java.lang.IllegalStateException: Cannot
       mark the transaction for rollback.
       xid=BEA1-00032CA83BB89E472B1E, status=Rolled back.
       [Reason=weblogic.transaction.internal.TimedOutException:
       Transaction timed out after 31 seconds
       BEA1-00032CA83BB89E472B1E]
          at
       org.eclipse.persistence.exceptions.TransactionException.errorMarkingTransactionForRollback(TransactionException.java:103)
          at
       org.eclipse.persistence.transaction.AbstractTransactionController.markTransactionForRollback(AbstractTransactionController.java:198)
          at
       org.eclipse.persistence.internal.jpa.transaction.JTATransactionWrapper.setRollbackOnlyInternal(JTATransactionWrapper.java:83)
          at
       org.eclipse.persistence.internal.jpa.EntityManagerImpl.setRollbackOnly(EntityManagerImpl.java:946)
          at
       org.eclipse.persistence.internal.jpa.EJBQueryImpl.setRollbackOnly(EJBQueryImpl.java:941)
          at
       org.eclipse.persistence.internal.jpa.EJBQueryImpl.getSingleResult(EJBQueryImpl.java:567)
          at
       com.gamyam.product.geoip.model.GeoIPServiceProvider.fetchLocation(GeoIPServiceProvider.java:159)
          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:597)
          at
       com.bea.core.repackaged.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:281)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:187)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:154)
          at
       com.bea.core.repackaged.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:126)
          at
       com.bea.core.repackaged.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:114)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
          at
       com.bea.core.repackaged.springframework.jee.spi.MethodInvocationVisitorImpl.visit(MethodInvocationVisitorImpl.java:15)
          at
       weblogic.ejb.container.injection.EnvironmentInterceptorCallbackImpl.callback(EnvironmentInterceptorCallbackImpl.java:54)
          at
       com.bea.core.repackaged.springframework.jee.spi.EnvironmentInterceptor.invoke(EnvironmentInterceptor.java:30)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
          at
       com.bea.core.repackaged.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
          at
       com.bea.core.repackaged.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:126)
          at
       com.bea.core.repackaged.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:114)
          at
       com.bea.core.repackaged.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
          at
       com.bea.core.repackaged.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:210)
          at $Proxy90.fetchLocation(Unknown Source)
          at
       com.gamyam.product.geoip.model.GeoIPService_2uw13f_GeoIPServiceImpl.fetchLocation(GeoIPService_2uw13f_GeoIPServiceImpl.java:610)
          at
       com.gamyam.product.geoip.model.GeoIPService_2uw13f_GeoIPServiceImpl_WLSkel.invoke(Unknown
       Source)
          at
       weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:589)
          at
       weblogic.rmi.cluster.ClusterableServerRef.invoke(ClusterableServerRef.java:230)
          at
       weblogic.rmi.internal.BasicServerRef$1.run(BasicServerRef.java:477)
          at
       weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
          at weblogic.security.service.SecurityManager.runAs(Unknown
       Source)
          at
       weblogic.rmi.internal.BasicServerRef.handleRequest(BasicServerRef.java:473)
          at
       weblogic.rmi.internal.wls.WLSExecuteRequest.run(WLSExecuteRequest.java:118)
          at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
          at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
       Caused by: java.lang.IllegalStateException: Cannot mark the
       transaction for rollback. xid=BEA1-00032CA83BB89E472B1E,
       status=Rolled back.
       [Reason=weblogic.transaction.internal.TimedOutException:
       Transaction timed out after 31 seconds
       BEA1-00032CA83BB89E472B1E]
          at
       weblogic.transaction.internal.TransactionImpl.throwIllegalStateException(TransactionImpl.java:1829)
          at
       weblogic.transaction.internal.TransactionImpl.setRollbackOnly(TransactionImpl.java:549)
          at
       weblogic.transaction.internal.TransactionManagerImpl.setRollbackOnly(TransactionManagerImpl.java:316)
          at
       weblogic.transaction.internal.TransactionManagerImpl.setRollbackOnly(TransactionManagerImpl.java:309)
          at
       org.eclipse.persistence.transaction.JTATransactionController.markTransactionForRollback_impl(JTATransactionController.java:145)
          at
       org.eclipse.persistence.transaction.AbstractTransactionController.markTransactionForRollback(AbstractTransactionController.java:196)
          ... 37 more
       Process exited with exit code 0.

       Here is my fetchLocation() method:
          public IPGroupCity fetchLocation(String ip){
              //String sql="SELECT * FROM `ip_group_city` where
       `ip_start` <= ((INET_ATON(?1))/256) order by ip_start desc
       limit 1";
              Query query = em.createNamedQuery("findLocationForIP");
              int ipNumber = GeoIPUtils.convertIPStringToNumber(ip);
              query.setParameter("ipNumber",ipNumber);
              query.setHint("eclipselink.jdbc.fetch-size",1);
              IPGroupCity location= (IPGroupCity)
       query.getSingleResult();
              return location;
          }/

       [/code]

       Can you help me find out why eclipselink could not fetch the
       result of my query?
       and what I need to to do to fix this...

       Thanks and Regards,
       Samba

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