Why transaction don't rollback when Exception hap

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

Hi everyone:

Now I use this pattern to write Hibernate code , I want to know if it is not safe or not correctly.

Code:

      Session session=null;
      Transaction tx=null;
try{
        session=HibernateUtil.currentSession();
        tx=session.beginTransaction();
        ..................................
        .............................
    }catch(Exception e){
          try{
                   tx.rollback();
               }catch(Exception e){
                    e.printStackTrace();
               }
   }finally{
           try{
                   HibernateUtil.closeSession();
               }catch(Exception e){
                    e.printStackTrace();
               }

   }
....................................................................

But if some Exception happened when webapp is running,JBoss is outofmemory frequently.
The image is in the following:

Why? I want to know if the session is not closed when Exception happened. Or the transaction don't rollback after Exception happened ?
The HibernateUtil is the right Hibernate docs's helper class.

Could someone give me any idea? THks!

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

The Image is the Following picture:

http://forum.javaeye.com/download.php?id=854[/list]

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

Sorry,the code should be this:

Code:

Session session=null; 
      Transaction tx=null; 
try{ 
        session=HibernateUtil.currentSession(); 
        tx=session.beginTransaction(); 
        .................................. 
        ............................. 
        tx.commit();
    }catch(Exception e){ 
          try{ 
                   tx.rollback(); 
               }catch(Exception e){ 
                    e.printStackTrace(); 
               } 
   }finally{ 
           try{ 
                   HibernateUtil.closeSession(); 
               }catch(Exception e){ 
                    e.printStackTrace(); 
               } 

   } 
.................................................................... 

max · **Posted:** Sun Dec 19, 2004 4:27 pm

OutOfMemoryError is an Error and not an Exception.

Use catch(Throwable) to catch them all.

(but note that with an outofmemoryerror you are not guaranteed much - their might not be enough memory to perform the rollback - and then it is up to the db not to commit the transaction..

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

Thank you Max.

You mean that I should enlarge my Linux Server's memory or Oracle10g's Memory? (The webapp running at Linux redhad and Oracle DB) .

What does "Use catch(Throwable) to catch them all" mean?
I already catch all the possible exception in my Code. How to catch them all? Could you give me some idea? Thanks!

max · **Posted:** Sun Dec 19, 2004 5:31 pm

Look at the inheritance hierachy of Throwable - Exception and Error extends from it. So, catch(Throwable) catches both Exception's and Errors.

Please read up on exception and error handling in java - nothing to do with hibernate ;)

max · **Posted:** Sun Dec 19, 2004 5:33 pm

and that you java vm runs out of memory means you should get more memory in your java vm....(or check if you have a memory leak ,)

anthony · **Posted:** Sun Dec 19, 2004 6:08 pm

Quote:

session=HibernateUtil.currentSession();
tx=session.beginTransaction();
..................................
.............................
tx.commit();

and what about showing what is under
................
................
?

are you doing massive insert update?

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

max wrote:

and that you java vm runs out of memory means you should get more memory in your java vm....(or check if you have a memory leak ,)

Thks max. I will change my code to following:

Code:

Session session=null; 
      Transaction tx=null; 
try{ 
        session=HibernateUtil.currentSession(); 
        tx=session.beginTransaction(); 
        .................................. 
        ............................. 
        tx.commit(); 
    }catch(Throwable e){ 
          try{ 
                   tx.rollback(); 
               }catch(Exception e){ 
                    e.printStackTrace(); 
               } 
   }finally{ 
           try{ 
                   HibernateUtil.closeSession(); 
               }catch(Exception e){ 
                    e.printStackTrace(); 
               } 

   } 

But the hibernate's docs all catch HibernateException only. For example,HibernateUtil helper class. Why hibernate's example all catch HibernateException instead of Throwable ?

I will try catch Throwable instead of Exception in the next Application test.
Our hibernate web application is accessed by 20 clients.

Quote:

get more memory in your java vm

What java vm paremeter should I set , I don't know whether 256 is enough. Expecting your suggestion. :)

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

anthony wrote:

Quote:

session=HibernateUtil.currentSession();
tx=session.beginTransaction();
..................................
.............................
tx.commit();

and what about showing what is under
................
................
?

are you doing massive insert update?

Hi anthony:

There are a insert and a update opperation between my commit block.

Should I do little database insert or update in one transaction? And do another database opperation in a new transaction?

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

anthony wrote:

Quote:

session=HibernateUtil.currentSession();
tx=session.beginTransaction();
..................................
.............................
tx.commit();

and what about showing what is under
................
................
?

are you doing massive insert update?

Another problem:

Should I close hibernate session after commit transaction per time? It is slow if I have many transaction opperation. I think it should be better if I do it the following way:

Code:

Session session=null; 
      Transaction tx=null; 
try{ 
        session=HibernateUtil.currentSession(); 
        tx=session.beginTransaction(); 
        .................................. 
        ............................. 
        tx.commit(); 
    }catch(Throwable e){ 
          try{ 
                   tx.rollback(); 
               }catch(Exception e){ 
                    e.printStackTrace(); 
               } 
   }

And in Servlet Filter ,I close the hibernate session finally.

I don't know whether it is the right way.

max · **Posted:** Wed Dec 22, 2004 4:35 am

i'll suggest you go read the chapters about transaction & session handling in applications in Hibernate In Action - they explain all this stuff

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

max wrote:

i'll suggest you go read the chapters about transaction & session handling in applications in Hibernate In Action - they explain all this stuff

Yes,I will read it . ;-)
Thks !