Re: poor performance

[Craig L Russell]

Hi,








Regards,

Craig

On Sep 5, 2008, at 10:09 AM, paul_deg wrote:

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.

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.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

pstm.setDate(4, new java.sql.Date(System.currentTimeMillis()));

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!

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