c3p0 with hibernate don't close connection

Question

I have a project using Hibernate JPA with persistence.xml and EntityManager

<property name="connection.provider_class"  value="org.hibernate.connection.C3P0ConnectionProvider"/>
     <!-- Important -->


  <property name="hibernate.c3p0.min_size" value="10"/>
  <property name="hibernate.c3p0.max_size" value="20"/>
    <property name="hibernate.c3p0.acquire_increment" value="1"/>
  <property name="hibernate.c3p0.minPoolSize" value="1"/>
  <property name="hibernate.c3p0.timeout" value="1800"/>
  <property name="hibernate.c3p0.max_statements" value="50"/>
  <property name="hibernate.c3p0.idle_test_period" value="3000"/>

I have a class EntityManagerHelper that is handling the EntityManager and EntityManagerFactory

public class EntityManagerHelper {

static Logger logger = Logger.getLogger(EntityManagerHelper.class);

private static final EntityManagerFactory emf; 
private static final ThreadLocal<EntityManager> threadLocal;

static {
    logger.warn("Criando EM Factory");
    emf = Persistence.createEntityManagerFactory("persistencia");      
    threadLocal = new ThreadLocal<EntityManager>();
}

public static EntityManager getEntityManager() {
    EntityManager em = threadLocal.get();

    if (em == null) {
        em = emf.createEntityManager();
        threadLocal.set(em);
    }
    return em;
}

public static void closeEntityManager() {
    EntityManager em = threadLocal.get();
    if (em != null) {
        logger.info("fechando Transação");
        em.close();
        threadLocal.set(null);
    }
}

public static void closeEntityManagerFactory() {
    logger.warn("Destroindo EM Factory");
    emf.close();
}

public static void beginTransaction() {
    logger.info("iniciando Transação");
    getEntityManager().getTransaction().begin();
}

public static void rollback() {
    getEntityManager().getTransaction().rollback();
}

public static void commit() {
    logger.info("commitando Transação");
    getEntityManager().getTransaction().commit();
} 
}

and I use this filter

public class JPAFilter implements Filter {

@Override
public void destroy() {}

@Override
public void init(FilterConfig fc) throws ServletException {}

@Override
public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain) throws IOException, ServletException {

        try {
            req.setAttribute("EntityManager", EntityManagerHelper.getEntityManager());
            EntityManagerHelper.beginTransaction();
            chain.doFilter(req, res);
            EntityManagerHelper.commit();
        } catch (RuntimeException e) {

            if ( EntityManagerHelper.getEntityManager() != null && EntityManagerHelper.getEntityManager().isOpen()) 
                EntityManagerHelper.rollback();
            throw e;

        } finally {
            EntityManagerHelper.closeEntityManager();
        }
}
public EntityManager  getEntityManager(){
    return EntityManagerHelper.getEntityManager();
}

}

but the connections are not closed with the seat, see below

PostgreSQL

Please point me to where I'm wrong.

Thanks in advance.

Answer 1

The connection pool is not about closing connection. Its all about the contrary situation - to keep connections alive and reuse them. It is much more efficient to keep live idle connections than to reestablish it on demand.

As a bonus, check https://www.mchange.com/projects/c3p0/ and Appendix C as some of your configuration properties are surplus and/or does not have any effect.