@JoinColumnsOrFormulas cause n+1 issue

Hibernate ORM
1

I am facing the n+1 query issue when I use @JoinColumnsOrFormulas or @JoinColumns with @NamedEntityGraph(includeAllAttributes = true)

I tried to also left join the entity in Specification and it also cause n+1 query issue.

Entity:

@Data
@Entity
@Table(name = "book")
@NamedEntityGraph(name = "all", includeAllAttributes = true)
public class BookEntity implements JpaEntity {

    @ManyToOne(targetEntity = CustomerEntity.class)
    @JoinColumnsOrFormulas({
            @JoinColumnOrFormula(column = @JoinColumn(name = "customer", referencedColumnName = "number", insertable = false, updatable = false)),
            @JoinColumnOrFormula(column = @JoinColumn(name = "sub_customer", referencedColumnName = "sub_number", insertable = false, updatable = false)),
            @JoinColumnOrFormula(formula = @JoinFormula(value = "'2019'", referencedColumnName = "year"))
    })
    private CustomerEntity customerEntity;
}

Repository:

@Override
    @EntityGraph(value = "all")
    Page<BookEntity> findAll(Specification<BookEntity> spec, Pageable pageable);

I see that the query is correct. I see the join for the first query, so it looks like I have the full entity and no need to make n+1 query. But after correct query I see additional selects for the CustomerEntity.

Can someone help me to avoid n+1 issue with this case? Maybe it is a bug.

2

Maybe entity graph annotation does not work on spring data jpa methods with specification and pageable.
Try to use https://github.com/Cosium/spring-data-jpa-entity-graph

3

Thank you, I will have a look!