Hello.
We are using Hibernate 3.3.1GA with Jboss 4.2.3GA.
Here is the relevant hibernate configuration:
<hibernate-configuration>
<session-factory name="java:hibernate/SessionFactory">
<!-- properties -->
<property name="connection.datasource">java:toluna_mssql_jdbc</property>
<property name="dialect">com.toluna.common.hibernate.SqlServerDialect</property>
<property name="hibernate.transaction.factory_class">org.hibernate.transaction.JTATransactionFactory</property>
<property name="hibernate.transaction.manager_lookup_class">
org.hibernate.transaction.JBossTransactionManagerLookup
</property>
<property name="hibernate.transaction.flush_before_completion">true</property>
<property name="hibernate.transaction.auto_close_session">true</property>
<property name="hibernate.connection.release_mode">after_transaction</property>
<property name="hibernate.connection.defaultNChar">true</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<property name="hibernate.cache.use_minimal_puts">true</property>
<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.max_fetch_depth">1</property>
<property name="hibernate.jdbc.batch_size">250</property>
<property name="current_session_context_class">thread</property>
<property name="hibernate.order_updates">true</property>
<property name="hibernate.jdbc.use_streams_for_binary">true</property>
...
Now my problem is that under heavy load I can see transactions that are never committed. As a result these transactions hold db locks forever (at least 1 hour till transaction timeout happens) and the whole system got stuck -- other transactions are waiting for the stucked one to release locks and so eventually Jboss threads are stuck.
I used SQL profiler and found easily the stuck transaction at the head of the waiting chain. There are 400+ SQL commands (most are selects) hanging on this transaction after last commit!
I must mark that without heavy load everything works fine.
Now our common usage of Hibernate session is like this:
We get the session at the Jboss backend when our EJB method is called:

Session s = SessionFactory.getCurrentSession();
s.beginTransaction();
//do EJB business logic
// there can be also s.flush() commands scattered here and there
// there can be local interface calls to other EJBs that have a similar structure as this one (As I know consequent s.beginTransaction() commands are ignored by Hibernate)
return;

As you see we don't do commit and don't close hibernate session and this is probably performed well by Hibernate.
Unless there is a heavy load in which case I suspect that Hibernate "forgets" to perform commit.
I can't add commits before return from every EJB call since there are inter-bean calls too and preliminary commits are very undesired.
Please help.

Dont use Hibernate query.Use the db query directly.

It will create n number of objects for n number of rows present in DB. so it will get Hang.

So Use the Database query directly.Do n't use Javaobject queries with hibernate when retrieving more records.


Ex: Select * from employee where emp.rec>=1000

Hope This Helps !

Thanks,
Kannan.