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<Post, Long> { // attributePaths specifies related entities to eagerly load @EntityGraph(attributePaths = {"author"}) List<Post> 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.