Hibernate - Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1

Question

I get following hibernate error. I am able to identify the function which causes the issue. Unfortunately there are several DB calls in the function. I am unable to find the

Answer 1

In my case, I came to this exception in two similar cases:

• In a method annotated with @Transactional I had a call to another service (with long times of response). The method updates some properties of the entity (after the method, the entity still exists in the database). If the user requests two times the method (as he thinks it doesn't work the first time) when exiting from the transactional method the second time, Hibernate tries to update an entity which already changed its state from the beginning of the transaction. As Hibernate search for an entity in a state, and found the same entity but already changed by the first request, it throws an exception as it can't update the entity. It's like a conflict in GIT.
• I had automatic requests (for monitoring the platform) which update an entity (and the manual rollback a few seconds later). But this platform is already used by a test team. When a tester performs a test in the same entity as the automatic requests, (within the same hundredth of a millisecond), I get the exception. As in the previous case, when exiting from the second transaction, the entity previously fetched already changed.

Conclusion: in my case, it wasn't a problem which can be found in the code. This exception is thrown when Hibernate founds that the entity first fetched from the database changed during the current transaction, so it can't flush it to the database as Hibernate doesn't know which is the correct version of the entity: the one the current transaction fetch at the beginning; or the one already stored in the database.

Solution: to solve the problem, you will have to play with the Hibernate LockMode to find the one which best fit your requirements.