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Hibernate getCurrentSession() do i really need a transaction for a read-only type of query?

I am trying to utilize Hibernate and am trying to avoid the management of session by utilizing the getCurrentSession() which is provided by the API SessionFactory. As I understand it, this will manage the session for me. My problem is when trying to use it in place of openSession(), I am getting an error saying that I need to have an active transaction. Online i have read conflicting answers, so i am still not sure. I am trying to execute a read only query (basically a select), why do i need a transaction for that? 

Error message: org.hibernate.HibernateException message: getNamedQuery is not valid without active transaction

More details:

Hibernate.cfg.xml - snippet

<hibernate-configuration>
<session-factory name="hibernateSessionFactory">
    <property name="connection.datasource">jdbc/DPARISC</property>
    <property name="hibernate.dialect">org.hibernate.dialect.DB2Dialect</property>
    <property    name="hibernate.current_session_context_class">org.hibernate.context.ThreadLocalSessionContext</property>
    <property name="hibernate.connection.isolation">1</property>

Nothing special in the way we create the SessionFactory

config.buildSessionFactory();

Now here is where the problem comes, on the createQuery

 Session session = HibernateUtil.getDB2SessionFactory().getCurrentSession();
    Query query = session.createQuery(queryStringBuilder.toString())
        .setParameter("orgId", request.getOrgId().intValue())
        .setParameter("busUnitId", request.getBusinessUnitId().intValue());
    query.setMaxResults(HibernateConstants.MAX_RESULTS);

Again the query is basically just a Select statement. Do i need to have a begin transaction and then a commit even for things like this when i use getCurrentSession()? Isnt that going to create a lot of overhead?

Solution

  • Short answers for your questions: yes and no.

    Longer answers:

    Hibernate requires you to have a session open when you perform anything. You can use getCurrentSession() only if you actually have opened one.

    Why do you assume it creates a lot of overhead?