Re: [eclipselink-users] NPE in DatabaseCall.translate() when page size i

[James Sutherland <jamesssss@xxxxxxxxx>]

I can't think of any reason why the query results would be empty.

Please include the JPQL query you are executing, and the SQL that
EclipseLink is generating, and verify that the SQL returns the number of
rows you are expecting.



Mohsen Saboorian wrote:
> 
> James,
> 
> Thanks for your help.
> 
> I've written the following code on my startup listener:
> 
> 	EntityManager em = PersistenceHelper.getEntityManager();
> 	EntityManagerImpl emi = (EntityManagerImpl) em.getDelegate();
> 	ServerSession serverSession = emi.getServerSession();
> 	DatabasePlatform plaf = serverSession.getPlatform();
> 
> 	((OraclePlatform) plaf).setShouldUseRownumFiltering(false);
> 
> serverSession.getClassDescriptor(org.mypackage.BaseClass.class).getInheritancePolicy()
> 			.setShouldOuterJoinSubclasses(true);
> 
> It resolved NPE problem, however the main issue is still there. When I
> count(*) my data in BaseClass entity it returns correct value, however
> when I want to get a page of the data, it returns an empty List.
> 
> Thanks,
> Mohsen.
> 
> I've voted for the bug.
> 
> On Mon, Aug 11, 2008 at 6:13 PM, James Sutherland <jamesssss@xxxxxxxxx>
> wrote:
>>
>> Seems to be a bug with maxResults and inheritance.  This bug has already
>> been
>> logged see,
>>
>> https://bugs.eclipse.org/bugs/show_bug.cgi?id=237743
>>
>> Please vote for the bug.
>>
>> As a wrokaround you can remove the maxResults, or call
>> setShouldUseRownumFiltering(false) on your OraclePlatform.
>>
>> You could also set inheritance to be loaded through an outerjoin, which
>> is
>> probably the best solution anyway if you want to set a maxResults.  There
>> is
>> an InhertiancePolicy and query option setShouldOuterJoinSubclasses(true)
>> that will configure this.  There is no annotation or query hint yet for
>> this, so you may wish to log a bug for that.
>>
>>
>>
>>
>> Mohsen Saboorian wrote:
>>>
>>> Hi,
>>>
>>> I have a base class (@Inheritance(strategy = InheritanceType.JOINED))
>>> with a number of subclasses, all with string discriminator values.
>>> When I rung the following query, I'm giving NPE exception: SELECT be
>>> FROM BaseEntity be
>>>
>>> If I do not set q.setFirstResult(0).setMaxResults(x) (x can be any
>>> number > 0, even if the size is more than query result), it works
>>> good, but as I set some maxResults, it throws the following exception.
>>>
>>> [EL Warning]: 2008.08.09
>>> 09:06:16.315--UnitOfWork(10250203)--java.lang.NullPointerException
>>> java.lang.NullPointerException
>>>       at
>>> org.eclipse.persistence.internal.databaseaccess.DatabaseCall.translate(DatabaseCall.java:925)
>>>       at
>>> org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:203)
>>>       at
>>> org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:190)
>>>       at
>>> org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:261)
>>>       at
>>> org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectAllRows(DatasourceCallQueryMechanism.java:594)
>>>       at
>>> org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRowsFromConcreteTable(ExpressionQueryMechanism.java:2496)
>>>       at
>>> org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingDefaultMultipleTableSubclassRead(InheritancePolicy.java:1265)
>>>       at
>>> org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingMultipleTableSubclassRead(InheritancePolicy.java:1299)
>>>       at
>>> org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRows(ExpressionQueryMechanism.java:2461)
>>>       at
>>> org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:478)
>>>       at
>>> org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:883)
>>>       at
>>> org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:666)
>>>       at
>>> org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:844)
>>>       at
>>> org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:456)
>>>       at
>>> org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:906)
>>>       at
>>> org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2588)
>>>       at
>>> org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1178)
>>>       at
>>> org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1162)
>>>       at
>>> org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1136)
>>>       at
>>> org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1118)
>>>       at
>>> org.eclipse.persistence.internal.jpa.EJBQueryImpl.executeReadQuery(EJBQueryImpl.java:399)
>>>       at
>>> org.eclipse.persistence.internal.jpa.EJBQueryImpl.getResultList(EJBQueryImpl.java:517)
>>>
>>>
>>> Thanks,
>>> Mohsen.
> 
> 


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