yannbriancon

@RunWith(MockitoJUnitRunner.class)
@SpringBootTest
@Transactional
class NPlusOneQueriesLoggingTest {

    @Autowired
    private MessageRepository messageRepository;

    @Test
    void nPlusOneQueriesDetection_isLoggingWhenDetectingNPlusOneQueries() {

yannbriancon

@RunWith(SpringRunner.class)
@SpringBootTest("hibernate.query.interceptor.error-level=ERROR")
@Transactional
class NPlusOneQueriesLoggingTest {
    ...
}

yannbriancon

@EntityGraph(attributePaths = {"author"})
List<Message> getAllBy();

yannbriancon

@Query("SELECT * 
        FROM Message m 
        LEFT JOIN FETCH m.author")
List<Message> getAllBy();

yannbriancon

List<Message> getAllBy() {
  CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
  
  CriteriaQuery<Message> query = criteriaBuilder.createQuery(Message.class);
  Root<Message> message = query.from(Message.class);
  // Add fetching of the author field
  message.fetch(Message_.author, JoinType.LEFT);
  query.select(message);
  
  TypedQuery<Message> typedQuery = entityManager.createQuery(query);

yannbriancon

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
  @EntityGraph(attributePaths = {"messages"})
  List<User> findTop5By();

  // JPQL does not support LIMIT
  // We need to use Pageable to set the number of ids we want
  @Query("SELECT id " +
         "FROM User ")
  List<Long> findIds(Pageable pageable);