that's not entirely true, a lot of resources are loaded at the last
minute, not necessarily when you think you initialised the call.
what I normally do if I'm trying to do a micro-benchmark like this is to
send the operation into something like a 110 time loop and only count
the times of the last 100. The first frew runs of something almost always
has unexpected results from random initialisations done etc. (not just
in jdbc/database tests but all tests).
On Fri, Sep 05, 2008 at 11:48:38AM -0700, pauldeg wrote:
>
> I am not actually counting start up costs, since I invoke StopWatch.start()
> _after_ EntityManagerFactory and EntityManager is initialized.
>
>
>
>
> Craig L Russell wrote:
> >
> > Hi,
> >
> > I think your test is probably dominated by startup costs. Initializing
> > the EntityManagerFactory involves much more than getting a JDBC
> > connection from the DriverManager.
> >
> > If your application typically starts a VM and inserts two objects,
> > then your example is probably fair.
> >
> > If your application does more work, it might be good to try to model
> > the entire workload.
> >
> > Regards,
> >
> > Craig
> >
> > On Sep 5, 2008, at 10:09 AM, paul_deg wrote:
> >
> >> I was thinking to switch to OpenJPA from Spring JDBC, just recently
> >> run
> >> a very simple test with 2 classes, SQL insert basically, the
> >> difference
> >> between plain JDBC and OpenJPA is more than 7 times!
> >> Why such poor performance? Below is my sample code and results, I used
> >> Enhancer as JVM argument, actually without it JPA result was almost
> >> twice faster!
> >>
> >> public static void main(String[] args) {
> >>
> >>
> >> Bill bill = new Bill();
> >> int id = new JVMRandom().nextInt(Integer.MAX_VALUE);
> >> bill.setId(id);
> >> bill.setCreated(new Date());
> >> bill.setPurchaseid(501253634);
> >> bill.setStatus(1);
> >>
> >> // System.out.println("bill id=" + id);
> >>
> >> Product prod = new Product();
> >> prod.setId(1);
> >>
> >> BillProduct bp = new BillProduct();
> >> bp.setBillid(bill);
> >> bp.setId(new JVMRandom().nextInt(Integer.MAX_VALUE));
> >> bp.setProductid(prod);
> >>
> >> StopWatch sw = new StopWatch();
> >>
> >> try {
> >> Class.forName("org.postgresql.Driver");
> >>
> >> String url =
> >> "jdbc:postgresql://localhost/mydb?user=admin&password=admin";
> >> Connection conn = DriverManager.getConnection(url);
> >> conn.setAutoCommit(false);
> >>
> >> // System.out.println("bill id=" + id);
> >> sw.start();
> >>
> >> PreparedStatement pstm = conn
> >> .prepareStatement("insert into bill(id, status,
> >> purchaseid, created) values (?, ?, ?, ?)");
> >> pstm.setInt(1, bill.getId());
> >> pstm.setInt(2, bill.getStatus());
> >> pstm.setInt(3, 501253634);
> >> pstm.setDate(4, new
> >> java.sql.Date(System.currentTimeMillis()));
> >> pstm.executeUpdate();
> >> pstm.close();
> >>
> >> pstm = conn
> >> .prepareStatement("insert into bill_product(id,
> >> productid, billid) values (?, ?, ?)");
> >> pstm.setInt(1, new JVMRandom().nextInt(Integer.MAX_VALUE));
> >> pstm.setInt(2, 1);
> >> pstm.setInt(3, bill.getId());
> >> pstm.executeUpdate();
> >> pstm.close();
> >>
> >> conn.commit();
> >> sw.stop();
> >>
> >> System.out.println("jdbc time=" + sw.getTime());
> >> conn.close();
> >>
> >> } catch (Exception e) {
> >> // TODO Auto-generated catch block
> >> e.printStackTrace();
> >> }
> >>
> >> sw.reset();
> >>
> >>
> >> //openjpa
> >> id = new JVMRandom().nextInt(Integer.MAX_VALUE);
> >> bill.setId(id);
> >> bp.setId(new JVMRandom().nextInt(Integer.MAX_VALUE));
> >>
> >> // persist
> >> EntityManagerFactory emf = Persistence
> >> .createEntityManagerFactory("testjpa");
> >> EntityManager em = emf.createEntityManager();
> >>
> >> sw.start();
> >>
> >> em.getTransaction().begin();
> >>
> >> em.persist(bill);
> >> em.flush();
> >> em.persist(bp);
> >>
> >> em.getTransaction().commit();
> >>
> >> sw.stop();
> >> System.out.println("openjpa time=" + sw.getTime());
> >>
> >> em.close();
> >>
> >> }
> >>
> >>
> >>
> >> *Console output: *
> >>
> >> jdbc time=78
> >> 93 testjpa INFO [main] openjpa.Runtime - Starting OpenJPA 1.2.0
> >> 203 testjpa INFO [main] openjpa.jdbc.JDBC - Using dictionary class
> >> "org.apache.openjpa.jdbc.sql.PostgresDictionary".
> >> openjpa time=547
> >>
> >>
> >>
> >
> > Craig L Russell
> > Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> > 408 276-5638 mailto:[EMAIL PROTECTED]
> > P.S. A good JDO? O, Gasp!
> >
> >
> >
> >
>
> --
> View this message in context:
> http://n2.nabble.com/poor-performance-tp841672p841878.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>
--
Ted Leung
[EMAIL PROTECTED]
The most important words I've learned to say - "I don't know".
