Spring JPA - @EntityGraph

By default, Spring Data JPA loads related data lazily, which can cause the N+1 problem — one query for the main data and more for each related item. @EntityGraph annotation fixes this by letting you load related data in a single query, without changing your entity mapping. It’s simple, improves performance, and avoids writing custom JOIN FETCH queries.

Example

Let’s say you have a Post entity that references an Author.

Entities

@Entity
public class Post {
    @Id
    private Long id;
    private String title;

    @ManyToOne(fetch = FetchType.LAZY)
    private Author author;
}

@Entity
public class Author {
    @Id
    private Long id;
    private String name;
}

Repository

public interface PostRepository extends JpaRepository {

    // attributePaths specifies related entities to eagerly load
    @EntityGraph(attributePaths = {"author"})
    List findAll();
}

Now, if you create a simple controller to return all posts and have SQL logging enabled, you'll see the queries printed in the console.

With @EntityGraph, only one query runs to fetch both the post and its author. Without it, multiple queries are executed — one for the posts and one for each author — which is the N+1 problem.

✅ Using @EntityGraph
Only one query — fast and efficient.

select p.id, p.title, a.id, a.name
from post p
left join author a on p.author_id = a.id

🚨 Not Using @EntityGraph
N+1 queries — slow and wasteful.

select * from post;
select * from author where id = ?;
select * from author where id = ?;

For more details on how to use @EntityGraph with Spring Data JPA, check out the official documentation.