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!
>
>
>
>
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