Hibernate version: 3.1

I would like to perform a transaction with large data amount using hibernate.

I get a "java.lang.OutOfMemoryError: Java heap space" error,
because Hibernate uses RAM (Hibernate Session) to store all data for actual transaction.

The database Oracle would use his rollback segment on disk which can be very large.

Can I call hibernate to use this oracle rollback segment instead of his Hibernate Session (RAM) to store data for transaction ?

u have to use batch processing for large data access from hibernate.

First set the jdbc.batch_size property to any number b/w 10 to 50 in hibernate.cfg.xml file.

if u r saving & update more no. of objects into DB. then check the loop index for batch size if it reaches that flush() and clear() the session.

Actually batch processing used for large number of objects accessing. for eg., if we r going to save 5000 users data without batch in middle of 1000 or some object the JVM show error Heap Memory Out exception.

for eg., how to use batch process for saving users object .

set jdbc.batch_size=30 in hibernate.cfg.xml file


for(int i=0;i<users.length;i++)
{
Users u =new Users();
u.setId(i);
....
if(i%30==0){
session.flush();
session.clear();
}
session.save(u); // session.update(u);
}

In this way we will deal with batch processing. it same procedure used in update also.

For more info.,
www.hibernate.org/hib_docs/reference/en/html/batch.html

Thank you very much for your very fast reply !!

Looking at your example my question is:
How can I save all the 5000 users in ONE transaction ?
If I set batch size to 30, than I only save 30 users in one transaction
and open a new one.
That is not exactly what I want to do.

flush() doesn't commit the data in the database. If the save() or update() was outside the for loop, the operation is still atomic.

Linhib.