Spring boot - 지연 로딩

orderItem이 3개 있는 order 조회시 생기는 쿼리문

    select
        orderitem0_.order_item_id as order_it1_4_0_,
        orderitem0_.count as count2_4_0_,
        orderitem0_.item_id as item_id6_4_0_,
        orderitem0_.order_id as order_id7_4_0_,
        orderitem0_.order_price as order_pr3_4_0_,
        orderitem0_.reg_time as reg_time4_4_0_,
        orderitem0_.update_time as update_t5_4_0_,
        item1_.item_id as item_id1_2_1_,
        item1_.item_detail as item_det2_2_1_,
        item1_.item_nm as item_nm3_2_1_,
        item1_.item_sell_status as item_sel4_2_1_,
        item1_.price as price5_2_1_,
        item1_.reg_time as reg_time6_2_1_,
        item1_.stock_number as stock_nu7_2_1_,
        item1_.update_time as update_t8_2_1_,
        order2_.order_id as order_id1_5_2_,
        order2_.meneber_id as meneber_6_5_2_,
        order2_.order_data as order_da2_5_2_,
        order2_.order_status as order_st3_5_2_,
        order2_.reg_data as reg_data4_5_2_,
        order2_.update_data as update_d5_5_2_,
        member3_.member_id as member_i1_3_3_,
        member3_.address as address2_3_3_,
        member3_.email as email3_3_3_,
        member3_.name as name4_3_3_,
        member3_.password as password5_3_3_,
        member3_.role as role6_3_3_ 
    from
        order_item orderitem0_ 
    left outer join
        item item1_ 
            on orderitem0_.item_id=item1_.item_id 
    left outer join
        orders order2_ 
            on orderitem0_.order_id=order2_.order_id 
    left outer join
        member member3_ 
            on order2_.meneber_id=member3_.member_id

orderItem 엔티티 조회시 order_item 테이블과 item, orders, member 테이블을 조인해서 한꺼번에 가져오고 있다

원하지 않는 데이터까지 같이 불러와져서 성능저하 문제가 생길 수 있다

 

*해결방법

FetchType.EAGER -> FetchType.LAZY

즉시 로딩

지연 로딩

*적용후

- orderItem안에 데이터를 사용할 떄만 join이 일어난다