Question

In a non-transactional environment, multiple rows can be deleted in a batch in Hibernate something like the following.

Session session=HibernateUtils.getSessionFactory().getCurrentSession();
session.beginTransaction();

String temp[]=request.getParameter("delIds").split(",");
int len=temp.length;
countryService.delete(temp);

Configuration configuration=new Configuration();
configuration.setProperty("hibernate.jdbc.batch_size", "50");

for(int i=0;i<len;i++)
{
    Country c=(Country)session.get(Country.class, new Long(temp[i]));

    if(i%50==0)
    {
         session.flush();
         session.clear();
    }

    session.delete(c);
}

//session.flush();
session.getTransaction().commit();

50 rows will be considered for deletion per batch.

---

How can the same be made possible in a transactional environment?

@Service
@Transactional(readOnly = true, propagation=Propagation.REQUIRES_NEW)

final public class CountryDAO implements CountryService
{
    private SessionFactory sessionFactory;

    public void setSessionFactory(SessionFactory sessionFactory)
    {
        this.sessionFactory = sessionFactory;
    }

    @SuppressWarnings("unchecked")
    @Transactional(readOnly=false, propagation=Propagation.REQUIRES_NEW)
    public void delete(String[] id)
    {
        int len=id.length;
        Session session=sessionFactory.getCurrentSession();

        for(int i=0;i<len;i++)
        {
            Country country=(Country)session.get(Country.class, Long.valueOf(id[i]));
            session.delete(country);
        }
    }
}

This works but how to delete rows in a batch with specific rows per batch so that a stream towards the database can be minimized?

---

I could do it something like the following.

@SuppressWarnings("unchecked")
//@Transactional(readOnly=false, propagation=Propagation.REQUIRES_NEW)
public void delete(String[] id)
{
    int len=id.length;
    Session session=sessionFactory.openSession();       //<----------------
    Transaction transaction = session.beginTransaction();

    Configuration configuration=new Configuration();
    configuration.setProperty("hibernate.jdbc.batch_size", "50");

    for(int i=0;i<len;i++)
    {
        if(i%49==0)
        {
            session.flush();
            session.clear();
        }
        Country country=(Country)session.get(Country.class, Long.valueOf(id[i]));
        session.delete(country);
    }
    transaction.commit();
    session.close();
}

According to the answer below.

Answer 1

You can use a “batch” update command that includes delete in the HQL.

http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/batch.html#batch-direct