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 Post subject: @NamedQuery + @NamedEntityGraph fetch doesn't work
PostPosted: Tue Sep 12, 2017 1:11 am 
Newbie

Joined: Tue Sep 12, 2017 12:48 am
Posts: 2
Hello, I'm Java beginner. I'm trying to use JPA with Hibernate and I've got an issue that I don't understand. It seems to me I found a bug, but maybe I'm doing something wrong.
For example I have two entities with OneToOne relation and EntityGraph to minimize queries count.

Code:
@Entity
@Data
public class Department {

    @Id
    @GeneratedValue
    private long id;

    private String name;

    @OneToMany(mappedBy = "department")
    private List<Person> persons;

    @OneToOne
    private DepartmentType type;

    @Override
    public String toString() {
        return "Department id=" + this.id + " " + this.name;
    }

}


@Entity
@NamedQuery(name = "departmetTypes",
            query = "select dt from DepartmentType dt",
            hints = {@QueryHint(name=QueryHints.HINT_LOADGRAPH, value = "DepartmentType.withDepartments")}
)
@NamedEntityGraph(name="DepartmentType.withDepartments", attributeNodes={@NamedAttributeNode("department")})
@Data
public class DepartmentType {

    @Id
    @GeneratedValue
    private Long id;

    private String name;

    @OneToOne(mappedBy="type")
    private Department department;
}


The following code gives only one query (as I wish)
Code:
public static void main(String[] args) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        EntityGraph gr = em.getEntityGraph("DepartmentType.withDepartments");
        em.createQuery("from DepartmentType", DepartmentType.class).setHint(QueryHints.HINT_LOADGRAPH, gr).getResultList().forEach(
                dt-> System.out.println(dt.getDepartment())
        );
        em.getTransaction().commit();

    }


Named query gives N+1 queries

Code:
    public static void main(String[] args) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.createNamedQuery("departmetTypes", DepartmentType.class).getResultList().forEach(
                p-> System.out.println(p.getDepartment()));
        em.getTransaction().commit();

    }


But named query with manually setted hint works correctly
Code:
public static void main(String[] args) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.createNamedQuery("departmetTypes", DepartmentType.class)
                .setHint(QueryHints.HINT_LOADGRAPH, em.getEntityGraph("DepartmentType.withDepartments"))
                .getResultList().forEach(
                p-> System.out.println(p.getDepartment()));
        em.getTransaction().commit();

    }

bun it looks like overhead. Can I use NamedQueries with EntiTyGraph hint?

Sorry for my English.


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 Post subject: Re: @NamedQuery + @NamedEntityGraph fetch doesn't work
PostPosted: Tue Sep 12, 2017 3:31 am 
Hibernate Team
Hibernate Team

Joined: Thu Sep 11, 2014 2:50 am
Posts: 1592
Location: Romania
It looks like a bug to me too. You should create a replicating test case using this template and open a Jira issue.

Thanks

_________________
If you liked my answer, you are going to love my High-Performance Java Persistence book and my blog as well.


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 Post subject: Re: @NamedQuery + @NamedEntityGraph fetch doesn't work
PostPosted: Tue Sep 12, 2017 5:16 am 
Newbie

Joined: Tue Sep 12, 2017 12:48 am
Posts: 2
I found that org.hibernate.annotations.NamedQuery doesn't contains "hints" definition while JPA does.

Code:
@Target( { TYPE, PACKAGE })
@Retention(RUNTIME)
@Repeatable(NamedQueries.class)
public @interface NamedQuery {

   /**
    * The name of this {@code NamedQuery}.
    */
   String name();

   /**
    * The query string for this {@code NamedQuery}.
    */
   String query();

   /**
    * The flush mode for this query.
    */
   FlushModeType flushMode() default FlushModeType.PERSISTENCE_CONTEXT;

   /**
    * Whether the query (results) is cacheable or not.  Default is {@code false}, that is not cacheable.
    */
   boolean cacheable() default false;

   /**
    * If the query results are cacheable, name the query cache region to use.
    */
   String cacheRegion() default "";

   /**
    * The number of rows fetched by the JDBC Driver per trip.
    */
   int fetchSize() default -1;

   /**
    * The query timeout (in seconds).  Default is no timeout.
    */
   int timeout() default -1;

   /**
    * A comment added to the generated SQL query.  Useful when engaging with DBA.
    */
   String comment() default "";

   /**
    * The cache mode used for this query.  This refers to entities/collections returned from the query.
    */
   CacheModeType cacheMode() default CacheModeType.NORMAL;

   /**
    * Whether the results should be read-only.  Default is {@code false}.
    */
   boolean readOnly() default false;
}


Code:
@Target({TYPE})
@Retention(RUNTIME)
public @interface NamedQuery {

    /**
     * (Required) The name used to refer to the query with the {@link EntityManager}
     * methods that create query objects.
     */
    String name();

    /** (Required)
     * The query string in the Java Persistence query language.
     */
    String query();

    /**
     * (Optional) The lock mode type to use in query execution.  If a <code>lockMode</code>
     * other than <code>LockModeType.NONE</code> is specified, the query must be executed in
     * a transaction.
     * @since Java Persistence 2.0
     */
    LockModeType lockMode() default NONE;

    /** (Optional) Query properties and hints.  May include
     * vendor-specific query hints.
     */
    QueryHint[] hints() default {};
}


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 Post subject: Re: @NamedQuery + @NamedEntityGraph fetch doesn't work
PostPosted: Tue Sep 12, 2017 5:19 am 
Hibernate Team
Hibernate Team

Joined: Thu Sep 11, 2014 2:50 am
Posts: 1592
Location: Romania
Add that to the issue as well.

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If you liked my answer, you are going to love my High-Performance Java Persistence book and my blog as well.


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