Out of memory error

ahmetaa · **Joined:** Fri Jan 23, 2004 10:26 am **Posts:** 21

Hello,
i am new to hibernate and trying to use it in a simple client server application. i hope i will try to explain well the situation.

1- i have a message class, which contains a client and a session object. , session object contains several session information and an Arraylist of event objects.

2 - Client side is producing an XML string for a message and sending it to server via sockets.

3- Server produces a reader thread for each incoming connection. server takes the XML message in the thread and produces an object from the XML string (using XStream, dont ask why i am converting to XML, is another issue..). Then it produces a persistent version of the message (including persistend versions of session, client id and events in it)

4- then it tries to insert it to the DB (HSQLDB) in the same socket reading thread.

For testing i am sending randomly produced messages sequentally from the client with 150ms intervals. if i send 100 messages, server handles it well but it seems it inserts each message after quite a delay.
When i tried to run two seperate client application, this time, after some time application gives me "Out of memory error".

my insertion code is stg like this (some lines of code is erased for simplification):

Code:

public class Inserter {
    Configuration cfg = new Configuration();
    public Inserter() throws MappingException {
        cfg.addClass(PMessage.class)
                .addClass(PSession.class)
                .addClass(PClient.class)
                .addClass(PEvent.class);
    }
    .....
    public void insertMessage(PMessage m) throws Exception {
        // configure hibernate
        SessionFactory sf = cfg.buildSessionFactory();
        // Open Session
        Session sess = sf.openSession();
        // start tr, save message and other objects within
        Transaction t = sess.beginTransaction();
        sess.save(m.getSession());
        sess.save(m.getClient());
        sess.save(m);
        t.commit();
        sess.close();
    }
}

have i understood the hibernate wrong? or stg wrong with my approach?
i can send some details of mapping files etc if anyone wants.
Thanks for this great software,

Ahmet

bertrand · **Posted:** Mon Feb 02, 2004 1:24 pm

Your insertMessage() method creates a SessionFactory every time it is invoked - and doesn't destroy it...

You should:
- create the SessionFactory once when your Inserter is initialized (for example - or at application init if you are using Hibernate at other places);
- then create a new session when you need to persist your message...

The SessionFactory is an heavy element that should be created only once and reused later when a session is needed...

ahmetaa · **Joined:** Fri Jan 23, 2004 10:26 am **Posts:** 21

Thanks!!!
i am trying it now. i was actually suspicious about that because the threads were not finishing. i wil post the further experiments.

ahmetaa · **Joined:** Fri Jan 23, 2004 10:26 am **Posts:** 21

perfect, it worked like a charm! i bombarded server with multiple clients and it saved all the messages very well. thanks a lot....

bertrand · **Posted:** Mon Feb 02, 2004 5:49 pm

ahmetaa wrote:

perfect, it worked like a charm! i bombarded server with multiple clients and it saved all the messages very well. thanks a lot....

Et voila... BTW you should have read the doc and examples...

emmanuel · **Posted:** Tue Feb 03, 2004 7:06 am

We could add a random RTM in signature :)

michael · **Posted:** Tue Feb 03, 2004 8:17 am

Probably we could autogenerate it according to the number of the posting in the thread, like first one - RTM, second one - RTFM, third one - sorry, thought it was in the manual, fourth one - okay, could be an interesting problem :)