[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-7304) NaturalIdResolutionCache not correctly filled on first persist when @GeneratedValue- at Id

[Guenther Demetz (JIRA)]

    [ https://hibernate.onjira.com/browse/HHH-7304?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=46580#comment-46580 ] 

Guenther Demetz commented on HHH-7304:
--------------------------------------

The problem is in first line not the unneccessary find-by-natural-id-query, this is surely overhead, but not really a bug.

The real problem is indeed, that the not-caching undermines the inline natural-synch process indroduced in hibernate4.1.2,
which relies on attached natural-id entities always having a concerning transactional natural-id cache entry.
In fact following testcase proves the bug, as suddenly natural-id-changes are not more recognized by the natural-id lookup:

{code:title=org.hibernate.test.jpa.naturalid.MutableNaturalIdTest.java|borderStyle=solid}
        @Test 
	@TestForIssue( jiraKey = "HHH-7304")
	public void testInLineSynchWithIdentityColumn() {
		Session s = openSession();
		s.beginTransaction();
		ClassWithIdentityColumn e = new ClassWithIdentityColumn();
		e.setName("Dampf");
		s.save(e);
		e.setName("Klein");
		assertNotNull(session.bySimpleNaturalId(ClassWithIdentityColumn.class).load("Klein"));

		session.getTransaction().rollback();
		session.close();
	}
{code}


Pull request is https://github.com/hibernate/hibernate-orm/pull/332

> NaturalIdResolutionCache not correctly filled on first persist when @GeneratedValue- at Id
> ---------------------------------------------------------------------------------------
>
>                 Key: HHH-7304
>                 URL: https://hibernate.onjira.com/browse/HHH-7304
>             Project: Hibernate ORM
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 4.1.3
>            Reporter: Frank Schwarz
>              Labels: natural-id, performance
>
> {code:title=Employee.java|borderStyle=solid}
> @Entity
> public class Employee{
>   @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private long id;
>   @NaturalId(mutable = true) private String name;
>   @NaturalId(mutable = true) private String surname;
>   private String position;
> }
> {code}
> {code:title=NaturalIdTest1.java|borderStyle=solid}
> entityManager.getTransaction().begin();
> Employee e = new Employee();
> e.setSurname("Hans");
> e.setName("Dampf");
> e.setPosition("Junior");
> entityManager.persist(e);
> entityManager.getTransaction().commit();
> Session session = entityManager.unwrap(Session.class);
> Employee e2 = (Employee) session.byNaturalId(Employee.class)
>     .using("surname", "Hans")
>     .using("name", "Dampf")
>     .load();
> System.out.println(e2);
> {code}
> {code:title=NaturalIdTest2.java|borderStyle=solid}
> entityManager.getTransaction().begin();
> Employee e = new Employee();
> e.setSurname("Hans");
> e.setName("Dampf");
> e.setPosition("Junior");
> entityManager.persist(e);
> // this is the only difference
> e.setPosition("Senior");
> entityManager.getTransaction().commit();
> Session session = entityManager.unwrap(Session.class);
> Employee e2 = (Employee) session.byNaturalId(Employee.class)
>     .using("surname", "Hans")
>     .using("name", "Dampf")
>     .load();
> System.out.println(e2);
> {code}
> The NaturalIdTest1 will issue an SQL statement for the find-by-natural-id-query; the NaturalIdTest2 does not.
> Put a breakpoint into NaturalIdResolutionCache#cache(Serializable, Object[]) and watch the pk-parameter to be {{null}} on the first invocation and not {{null}} on the second invocation.
> If the @Id-field is not @GeneratedValue, the first invocation of NaturalIdResolutionCache#cache will be already correct.

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