A coffee during the creation of the session ?

reivax57 · **Joined:** Fri Jul 13, 2007 11:53 am **Posts:** 4

Hi,

I test NHibernate 1.2 with VS2005 and Oracle10g. I wrote this code :

Code:

namespace ormsamples {
    public class CreateDonneesData {
        private void CreateData()
        {
            ISessionFactory sessions = new Configuration().Configure().BuildSessionFactory();
            ISession s = sessions.OpenSession();
            ITransaction t = s.BeginTransaction();
            try 
            {
                //...

                t.Commit();
            }
            catch(Exception e) {
                t.Rollback();
            }
            s.Close();
            sessions.Close();
        }
        // ...
    }
}

hibernate.cfg.xml :

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration  xmlns="urn:nhibernate-configuration-2.0" >
   <session-factory name="localfactory">
      <!-- properties -->
      <property name="hibernate.connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
      <property name="hibernate.dialect">NHibernate.Dialect.Oracle9Dialect</property>
      <property name="hibernate.connection.driver_class">NHibernate.Driver.OracleDataClientDriver</property>
      <property name="hibernate.connection.connection_string">User ID=Owner_Sgl_6;Password=idem;Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp) (HOST=10.99.100.5)(PORT=1520))(CONNECT_DATA=(SERVICE_NAME=ANAPDEV)))</property>
      <property name="show_sql">false</property>
      <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
<!--      <property name="use_outer_join">false</property> -->
<!--      <property name="max_fetch_depth">3</property> -->
<!--      <property name="use_reflection_optimizer">false</property> -->
      <!-- mapping files -->
      <mapping assembly="NHibernate.Test" />
   </session-factory>
</hibernate-configuration>

When I create the ISessionFactory variable, it takes 30-50 SECONDS !!

I test some options in the cfg.xml file but it's still the same. Have you got an idea ?

Thank's
Xavier.

merge_s.rottem · **Joined:** Tue Aug 23, 2005 5:52 am **Posts:** 335

Creating a SessionFactory *is* expensive and should only be done once for the lifetime of the application (in general). You then create Sessions from the factory when you need them.

You certainly shouldn't create a new SessionFactory for every Session.

Symon.

DavyBrion · **Posted:** Sat Jul 14, 2007 10:24 am

creating a SessionFactory is expensive, but 30-50 seconds is a long time. Do you have a very large amount of mapping files or something?

PandaWood · **Joined:** Wed Oct 25, 2006 10:51 pm **Posts:** 71

I think we need to be more precise here? How do we know exactly what's taking 50 seconds - there's no timings in your code.
It could be taking 50 seconds to log in to your database.
Have you eliminated obvious problems with your database connection that you might be having from your machine? Like by using a profiler or something?

reivax57 · **Joined:** Fri Jul 13, 2007 11:53 am **Posts:** 4

30-50 seconds is only on the BuildSessionFactory(). I've tested the SQLPlus connection and it's fast. I have 220 tables in the database schema and some transitive relations between tables.

So, it is possible to create the SessionFactory at the server's start and to get it on the client side each time it'is necessary ?

Xavier.

reivax57 · **Joined:** Fri Jul 13, 2007 11:53 am **Posts:** 4

30-50 seconds is only on the BuildSessionFactory(). I've tested the SQLPlus connection and it's fast. I have 220 tables in the database schema and some transitive relations between tables.

So, is it possible to create the SessionFactory at the server's start and to get it on the client side each time it'is necessary ?

Xavier.

merge_s.rottem · **Joined:** Tue Aug 23, 2005 5:52 am **Posts:** 335

I think it might be necessary to explain the architecture of your application for anyone to answer that properly. Is it a web app, are you using remoting, etc.

Symon.

reivax57 · **Joined:** Fri Jul 13, 2007 11:53 am **Posts:** 4

You're right.

It's a 3-layers C# WinForm project. Servers and PCs are on the same local network. There's no remoting.
After, we will develop a web module.

Xavier.

DavyBrion · **Posted:** Mon Jul 16, 2007 4:27 am

if i were you i'd go for the 'disconnected' approach... keep the SessionFactory and the Sessions completely server side, and return your objects to the client layer... let the client layer manipulate the objects in whichever way needed and then send them back to the server. Re-attach your objects to a new nhibernate session server-side and persist the objects. Keep the session lifetimes as short as possible (eg, one session per round-trip)

There are some pitfalls to this approach... You need to explicitely load every lazy-loaded association that will be needed in the current user story server-side before sending your objects back to the client. If you try to access a lazy-loaded property which wasn't initialized server-side you'll get a LazyInitializationException. Another way is to simply go back to the server if you realize you need more related data. Also, you'll lose the NHibernate default dirty tracking. When you reattach your objects to a new session, NHibernate has no way of checking which ones are dirty and which ones aren't. So you'll probably want to implement your own dirty tracking mechanism (which is fairly easy to do even though it is a bit tedious).

For some, this might not seem like a good approach... it's certainly not the easiest way to use nhibernate, but this way you can make sure your clients can't access the database without going through the application server first.