Hibernate - StaleObjectStateException in query possible?

Question

Is it possible to get a StaleObjectStateException with Hibernate when you do the same query twice inside one tx if the result data of that query gets changed by a concurrent update inside a different session between the first and the second query?

I am using optimistic concurrency control on all entities in this scenario.

So it looks like this.

Thread-1: Transaction begins
Thread-1: query gets executed and retrieves i.e order with key=4711
Thread-2: same order with key 4711 gets retrieved, changed and committed in second thread
Thread-1: query gets executed again and should return order with key=4711

Will I get a StaleObjectStateException in Thread-1 in the second query?

Thanks for your help!

Thomas

Answer 1

I don't think so. The second query in Thread-1 doesn't even hit the database, you'll get the (stale) object from the 1st level cache (the Session). But if you change the order after the second query, you'll get the exception when flushing the session.

Answer 2

Disclaimer: I have not tried it, this is what is expect from what I know of hibernate.

You will not get a StaleObjectStateException when executing the second query nor when the transaction from thread-1 is commited.

However, if if the order was modified before the second query is executed, the order will get flushed (assuming auto-flush mode and read-write transaction) right before the second query gets executed and this will trigger a StaleObjectStateException.