Hi,

Can i share hibernate session between multiple thread to save data?like...

ArrayList<Thread> threadList = new ArrayList<Thread>();

Transaction tx = session.beginTransaction(); // Start Transaction
for(Object object : objectList ){
PersistantThread persistantThread = new PersistantThread(session,object);
threadList.add(persistantThread);
persistantThread.start();
}
for(Thread thread : threadList){
thread.join();
}
session.flush();
tx.commit();

class PersistantThread extends Thread {
Object object = null;
Session session = null;

public PersistantThread(Session session,Object object){
this.session = session;
this.object = object;
}

public void run(){
try{
session.save(object);
}catch(Exception ex){
ex.printStackTrace();
}
}
}

In this case i am getting error like
sometime it is "org.hibernate.AssertionFailure: entity was persistent" and sometime "org.hibernate.AssertionFailure: object already associated, but no entry was found".

Can anyone have any idea how can we share the hibernate session with mutiple thread.

Thanks in Advance.

To my knowledge, the session was not designed that way and I really think you should rethink your design. If you go forward with this, I would strongly suggest that you wrap the the hibernate Session and synchronize methods. Expect to have problems though.

My advice is rethink your design.

Thanks pppoole.

So i need to either synchronize the code block or to make it single threaded. like this, right ?

public void run(){
try{
synchronized (session){
session.save(object);
}
}catch(Exception ex){
ex.printStackTrace();
}
}

Is there any other way to achieve multiple threading ?

Or any other way to speedup the db inserts?

Thanks

What I really meant by wrapper was to create an object that encapsulates the session and provides synchronized methods that delegate the calls to the hibernate session...



Again, I would recommend you rethink the design and not try to access the session with multiple threads. I can't see how you will easily coordinate the object states between the two states...

I have to agree with pppoole. Don't try to make sessions work in multiple threads. It will give you problems sooner or later. Some things like lazy loading are also hard to synchronize, since it may happen anytime you call a getter method on an object.

atulprajapati - if you have found my answers helpful, please rate it. It is frustrating to answer posts and then not get any credit...

Thanks.

@Beginner : If you have to use synchronized that way, then you better not use multiple threads. Its as good as a single thread.

Lazy initialization may be a problem, but then, in case of bulk inserts/updates for e.g., this is very efficient. You probably may need to make sure that the objects you spread across the threads have no linkling to each other. If they have, they could overrun each other results unpredictably without any notice.

So, its a good idea to do it, but firstly you need to know really good what you are doing, and do it in exceptional cases (e.g. write behinds, batch processing, etc.)