[Springframework-developer] Batch processing with hibernate

[Meyer, S. <S....@S2...>]

Hi,

We need batch processing support for hibernate. The processing should
take place in one transaction and the list of processed entities must be
selected with "select ... For update". HibernateTransactionManager does
not support this. The reason is presumably that the first-level cache
does not support rollbacks. I think that it is possible nevertheless if
you follow the following rules:

1. flush before setting a savepoint
2. clear the session before rolling back to a savepoint

The consequences of the second point are usually not a problem in batch
processing. Consider the recommended approach:

--------------  hibernate.org

Session session =3D sessionFactory.openSession();
Transaction tx =3D session.beginTransaction();
  =20
ScrollableResults customers =3D session.getNamedQuery("GetCustomers")
    .setCacheMode(CacheMode.IGNORE)
    .scroll(ScrollMode.FORWARD_ONLY);
int count=3D0;
while ( customers.next() ) {
    Customer customer =3D (Customer) customers.get(0);
    customer.updateStuff(...);
    if ( ++count % 20 =3D=3D 0 ) {
        //flush a batch of updates and release memory:
        session.flush();
        session.clear();
    }
}
  =20
tx.commit();
session.close();

-------------

Clearing the session after or before processing an entity returned from
the cursor will only result in slower performance  when loading certain
entities.

We have implemented this kind of batch processing but support by
hibernateTransactionManager would make our life a lot easier.



--
Stefan Meyer
Entwicklung

s....@s2...
T: +49.40.80 81 69-347

SinnerSchrader Neue Informatik
>> Software. Design. Interfaces.
http://www.s2neueinformatik.de/
 =20