Spring Content. Hibernate executes 3 queries to fetch image for each product

Question

I have a products page. Each listed product has its own image. To display it on view I use this line <img th:src="@{/data/{id}(id=${product.id})}"

When I'm going to the endpoint to see products, Hibernate generates 7 queries instead of 1.

Hibernate: 
    select
        product0_.id as id1_0_,
        product0_.content_id as content_2_0_,
        product0_.content_length as content_3_0_,
        product0_.mime_type as mime_typ4_0_,
        product0_.name as name5_0_ 
    from
        product product0_
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?

Probably, the problem is connected to the way how I receive the image on the page. I assume it happens like that: ProductRepository normally executes 1 query to get list of products. Then to show image on page Spring executes 3 queries for each product. Also I noticed that endpoint with image "/data/1" produces 3 queries.

Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?
Hibernate: 
    select
        product0_.id as id1_0_0_,
        product0_.content_id as content_2_0_0_,
        product0_.content_length as content_3_0_0_,
        product0_.mime_type as mime_typ4_0_0_,
        product0_.name as name5_0_0_ 
    from
        product product0_ 
    where
        product0_.id=?

How to optimize this process and execute less queries? Project to demonstrate the problem

https://github.com/leonaugust/hibernate-problem

Code:

@SpringBootApplication
@Controller
@EnableJpaRepositories
public class HibernateProblemApplication {

  @Autowired
  private ProductRepository repository;

  public static void main(String[] args) {
    SpringApplication.run(HibernateProblemApplication.class, args);
  }

  @GetMapping("/")
  public String getAll(Model model) {
    model.addAttribute("products", repository.findAll());
    return "products";
  }

  @Bean
  public CommandLineRunner uploadImages(ProductRepository repository,
      ProductImageStore store) {
    return (args) -> {
      Product chicken = new Product("Chicken");
      store.setContent(chicken, this.getClass().getResourceAsStream("/img/chicken.jpg"));
      repository.save(chicken);

      Product goose = new Product("Goose");
      store.setContent(goose, this.getClass().getResourceAsStream("/img/goose.jpg"));
      repository.save(goose);
    };
  }

}


@StoreRestResource(path = "data")
@Repository
public interface ProductImageStore extends ContentStore<Product, String> {
}


@Repository
public interface ProductRepository extends JpaRepository<Product, Long> {

}


@Entity
public class Product {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  private String name;

  @ContentId
  private String contentId;

  @ContentLength
  private Long contentLength = 0L;

  @MimeType
  private String mimeType = "text/plain";

  public Product(String name) {
    this.name = name;
  }

}

Answer 1

@leonaugust thanks for bringing this to my attention. Turns out our rest controller wasn't very smart and was doing more queries than it needed to. Fixed in the 1.2.1 release.