JPA / Eclipselink CursoredStream Error

Question

Hi there!
I have to do a database request on an Oracle XE database which returns about 1 million entities. As it does not make sense to load all of them to memory, I chose a Cursored Stream to do the work.
My code:
                /* count nbo entities */
                ReadAllQuery query = new ReadAllQuery(Entity.class);
                query.useCursoredStream(5, NBO_ENTITIES_TO_BE_READ_PER_CHUNK);
                /* disable caching */
                query.doNotCacheQueryResults();
                CursoredStream stream =
                        (CursoredStream) ((EntityManagerImpl) _entityManager).getSession()
                                .executeQuery(query);
                 * run through cursor
                while (!stream.atEnd()) {
                    List<Entity> entities = null;
                    try{
                    entities = stream.read(NBO_ENTITIES_TO_BE_READ_PER_CHUNK);
                    }catch(Exception e ){
                        e.printStackTrace();
                    doSomeWork( entities);
                    stream.releasePrevious();
                stream.close();The statement does fine with the first loads of data. However, while reading the last chunk of data, the following error happens:
xception Description: An attempt to read beyond the end of stream occurred.
Query: ReadAllQuery(referenceClass=Entity)
     at org.eclipse.persistence.exceptions.QueryException.readBeyondStream(QueryException.java:937)
     at org.eclipse.persistence.queries.CursoredStream.copy(CursoredStream.java:117)
     at org.eclipse.persistence.queries.CursoredStream.read(CursoredStream.java:327)
     at de.optware.dataloader.service.LieferantenstandortListService$1.run(LieferantenstandortListService.java:91)
     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
     at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
     at java.lang.Thread.run(Thread.java:662)I am using eclipselink 1.1.2 and the ojdbc14 jdbc driver.
Any ideas?
Edited by: user12188472 on 05.05.2011 01:40
Edited by: user12188472 on 05.05.2011 01:44

Answer 1

>
          tx.commit();
     if(em.isOpen())
          em.flush();
     em.clear();
     }catch (Exception e) {
          e.printStackTrace();
sry my bad ... em.flush() is the culprit