Count entity after a entity manager save - spring-data-jpa

Question

community,
i have a problem to count entities after a entitymanager#save in the same transaction. The problem is, that i get always an inexpected count. I would like to count the current rows of a entity after a entitymanager save, but the result is always the current row count + the saved entity (which are not commited yet). It looks like a classic dirty read issue.
For this reason i use Propagation.REQUIRES_NEW and Isolation.REPEATABLE_READ to count only the commited entities.
If I use a h2 database the result is the result which i expected, but if i use MYSQL there is another result.
Here some code snippets:
The service:
#Service
public class MyTestService {
#Autowired
private EntityRepository entityRepository;
#Transactional
public void doSomeLogic() {
entityRepository.save(new Entity());
final long count = count();
if (count != 0) {
throw new IllegalStateException("Entity count should be 0 but is " + count);
}
}
#Transactional(propagation = Propagation.REQUIRES_NEW, isolation = Isolation.REPEATABLE_READ)
public long count() {
return entityRepository.count();
}
}
The repo:
public interface EntityRepository extends PagingAndSortingRepository<Entity, Long>, JpaSpecificationExecutor<Entity> {
// #Override
// #Transactional(readOnly = true, propagation = Propagation.REQUIRES_NEW,
// isolation = Isolation.REPEATABLE_READ)
// long count();
}
The test:
#RunWith(SpringRunner.class)
#SpringBootTest
public class DemoApplicationTests {
#Autowired
private MyTestService myTestService;
#Test
public void testEntityCounterWithMultiThreads() {
myTestService.doSomeLogic();
}
}
If i uncomment the repository code, all works, but I don't understand the difference.
Anybody knows where is my thinking blunder?