I noticed an interesting behaviour of Hibernate transaction when testing tx.rollback(). I loaded an existing record from database, updated one of the fields and saved it. Then I called tx.rollback(). The record was not updated in database, which was the expected behaviour of a rollback. However, if I create a new object and save it, tx.rollback() does not seem to work. The new object will always be persisted, even if tx.rollback() is called. Just wondering if this is the intended behaviour of tx.rollback(). I used a MySQL database for the testing.

Did you flush the session before rolling back? This syncs with the db and thus enables it for rollback. Alternative is the evict it from the session cache.

Here is the testing code:


session.flush() does not seem to make a difference. I will test session.evict() method to see if it works.

A couple of things. Someone correct me if I'm wrong, but unless you are using the new transactional tables in MySQL, then you can sit there all day and rollback and nothing will happen.

Also, if using the Transaction API, you do not need to use session.flush(). Just call tx.commit() when ready to save.

As for the expected behaviour of tx.rollback(), again someone please correct me if I'm wrong, but you already saved the object, so what you are rolling back from?

John

MySQL requres the InnoDB table subsystem for transactions to work correctly.

It is true the tx.commit has an implied session.flush() so it is not required to flush before a tx.commit() but there are times when you might want to flush but not commit the transaction straight away. Note: Don't flush unless its necessary as it can have a performance penalty.

The session.save() sets up the sql operation, session.flush() sends the sql operation to the database, and finally tx.commit causes the change to be permanent.

Silly me. I forgot about this MySQL InnoDB type. Now the rollback works perfectly once I use InnoDB tables for testing. I usually don

No problem,

Off topic but there are a few brisbane based hibernate users. Maybe we should get together for a beer as its getting hot in brisbane here now. Temp of 35 and no air conn is not the best conditions to do any thinking.

Brisbane: Hibernate capital of the world :)

Seriously, I would be totally up for that. Maybe we could organise it in a miscellaneous forum thread?

P.S. Why the #$%@ don't you have air conditioning? Are you MAD? :)