SpringBoot Part4 9. LIVE SECTION

질의 응답

OSIV 패턴

spring:
  datasource:
    driver-class-name: org.h2.Driver
    url: jdbc:h2:~/order-live;DB_CLOSE_ON_EXIT=FALSE
    username: sa
    password:
  jpa:
    open-in-view: false # OSIV 설정
    hibernate:
      ddl-auto: create
    show-sql: true
    properties:
      hibernate.format_sql: false
server:
  servlet:
    encoding:
      charset: UTF-8
      enabled: true
      force: true

N+1 문제

@Transactional
public void test() {
    List<Order> all = orderRepository.findAll();
    all.forEach(it -> log.info("{}", it.getOrderItems().get(0).getPrice()));

    log.info("END");
}

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Hibernate: select order0_.id as id1_3_, order0_.created_at as created_2_3_, order0_.created_by as created_3_3_, order0_.member_id as member_i7_3_, order0_.memo as memo4_3_, order0_.order_datetime as order_da5_3_, order0_.order_status as order_st6_3_ from orders order0_
Hibernate: select orderitems0_.order_id as order_id7_2_0_, orderitems0_.id as id1_2_0_, orderitems0_.id as id1_2_1_, orderitems0_.created_at as created_2_2_1_, orderitems0_.created_by as created_3_2_1_, orderitems0_.item_id as item_id6_2_1_, orderitems0_.order_id as order_id7_2_1_, orderitems0_.price as price4_2_1_, orderitems0_.quantity as quantity5_2_1_ from order_item orderitems0_ where orderitems0_.order_id=?
2021-10-07 15:31:13.650  INFO 43372 --- [           main] c.k.lecture.order.service.OrderService   : 1000
Hibernate: select orderitems0_.order_id as order_id7_2_0_, orderitems0_.id as id1_2_0_, orderitems0_.id as id1_2_1_, orderitems0_.created_at as created_2_2_1_, orderitems0_.created_by as created_3_2_1_, orderitems0_.item_id as item_id6_2_1_, orderitems0_.order_id as order_id7_2_1_, orderitems0_.price as price4_2_1_, orderitems0_.quantity as quantity5_2_1_ from order_item orderitems0_ where orderitems0_.order_id=?
2021-10-07 15:31:13.653  INFO 43372 --- [           main] c.k.lecture.order.service.OrderService   : 1000
Hibernate: select orderitems0_.order_id as order_id7_2_0_, orderitems0_.id as id1_2_0_, orderitems0_.id as id1_2_1_, orderitems0_.created_at as created_2_2_1_, orderitems0_.created_by as created_3_2_1_, orderitems0_.item_id as item_id6_2_1_, orderitems0_.order_id as order_id7_2_1_, orderitems0_.price as price4_2_1_, orderitems0_.quantity as quantity5_2_1_ from order_item orderitems0_ where orderitems0_.order_id=?
2021-10-07 15:31:13.655  INFO 43372 --- [           main] c.k.lecture.order.service.OrderService   : 1000
2021-10-07 15:31:13.655  INFO 43372 --- [           main] c.k.lecture.order.service.OrderService   : END

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hibernate.default_batch_fetch_size

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