openjpa-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Albert Lee (JIRA)" <j...@apache.org>
Subject [jira] Created: (OPENJPA-359) OptimisticLockException NOT thrown for entity using Timestamp Version when update from current persistence contexts
Date Sat, 08 Sep 2007 05:04:30 GMT
OptimisticLockException NOT thrown for entity using Timestamp Version when update from current
persistence contexts
-------------------------------------------------------------------------------------------------------------------

                 Key: OPENJPA-359
                 URL: https://issues.apache.org/jira/browse/OPENJPA-359
             Project: OpenJPA
          Issue Type: Bug
          Components: jdbc
    Affects Versions: 1.0.0
         Environment: WIntel 32 
            Reporter: Albert Lee
            Priority: Minor


We ran a test using Timestamp as the version field in an entity, the following (pseudo) test
failed when an OptimisticLockException is expected:

    em1.persist( e0(pk1) );

    e1 = em1.find(pk1);
    e2 = em2.find(pk1);

    e1.setAttr( "new1");
    e2.setAttr( "new2");

    em1.merge( e1 );
    em2.merge( e2 );    <<<< Expect an OptimisticLockException

The cause of this problem is because the TimestampVersionStrategy.nextVersion returns a java.sql.Timestamp(System.currentTimeMillis());
In the Wintel environment, the currentTimeMillis() only has approximately 15ms resolution.
When 2 subsequent Timestamp version objects are requested within this 15ms interval, both
has the same version value. Therefore the em2.merge does not detected the versions difference
between o1 and o2, hence no exception is thrown.

Due to this behavior, the same test case may failed intermittenly depends on the currentTimeMillis()
resolution and the time when a timestamp version is created.  From some preliminary tests,
the resolution for  wintel, linux and z/os are about 15ms, 2ms and 2ms respectively.
    


-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message