인프런 커뮤니티 질문&답변

안녕하세요. 언제나 좋은 강의 너무 감사드립니다.

다름이 아니라 본영상에 8:43초 쯤에 나오는 EntityGraphType이 FETCH 타입과 LOAD타입이 있는데요.

@EntityGraph(value ="Study.withTagsAndManagers", type = EntityGraph.EntityGraphType.FETCH)
Study findStudyWithTagsByPath(String path);

이것의 타입을 FETCH로 해서  태그를 더하는 액션을 취할경우, 다음과 같은 SQL이 발생합니다.

2020-05-17 09:34:12.745 DEBUG 8292 --- [io-8080-exec-10] org.hibernate.SQL                        : 
    select
        study0_.id as id1_4_0_,
        tag2_.id as id1_9_1_,
        account4_.id as id1_0_2_,
        study0_.closed as closed2_4_0_,
        study0_.closed_date_time as closed_d3_4_0_,
        study0_.full_description as full_des4_4_0_,
        study0_.image as image5_4_0_,
        study0_.path as path6_4_0_,
        study0_.publish_date_time as publish_7_4_0_,
        study0_.published as publishe8_4_0_,
        study0_.recruit_update_date_time as recruit_9_4_0_,
        study0_.recruiting as recruit10_4_0_,
        study0_.short_description as short_d11_4_0_,
        study0_.title as title12_4_0_,
        study0_.use_banner as use_ban13_4_0_,
        tag2_.title as title2_9_1_,
        tags1_.study_id as study_id1_7_0__,
        tags1_.tags_id as tags_id2_7_0__,
        account4_.bio as bio2_0_2_,
        account4_.email as email3_0_2_,
        account4_.email_check_token as email_ch4_0_2_,
        account4_.email_check_token_generated_at as email_ch5_0_2_,
        account4_.email_verified as email_ve6_0_2_,
        account4_.joined_at as joined_a7_0_2_,
        account4_.location as location8_0_2_,
        account4_.nickname as nickname9_0_2_,
        account4_.occupation as occupat10_0_2_,
        account4_.password as passwor11_0_2_,
        account4_.profile_image as profile12_0_2_,
        account4_.study_created_by_email as study_c13_0_2_,
        account4_.study_created_by_web as study_c14_0_2_,
        account4_.study_enrollment_result_by_email as study_e15_0_2_,
        account4_.study_enrollment_result_by_web as study_e16_0_2_,
        account4_.study_updated_by_email as study_u17_0_2_,
        account4_.study_updated_by_web as study_u18_0_2_,
        account4_.url as url19_0_2_,
        managers3_.study_id as study_id1_5_1__,
        managers3_.managers_id as managers2_5_1__ 
    from
        study study0_ 
    left outer join
        study_tags tags1_ 
            on study0_.id=tags1_.study_id 
    left outer join
        tag tag2_ 
            on tags1_.tags_id=tag2_.id 
    left outer join
        study_managers managers3_ 
            on study0_.id=managers3_.study_id 
    left outer join
        account account4_ 
            on managers3_.managers_id=account4_.id 
    where
        study0_.path=?
2020-05-17 09:34:12.745 TRACE 8292 --- [io-8080-exec-10] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [VARCHAR] - [aaaa]
2020-05-17 09:34:12.748 DEBUG 8292 --- [io-8080-exec-10] org.hibernate.SQL                        : 
    select
        tags0_.account_id as account_1_1_0_,
        tags0_.tags_id as tags_id2_1_0_,
        tag1_.id as id1_9_1_,
        tag1_.title as title2_9_1_ 
    from
        account_tags tags0_ 
    inner join
        tag tag1_ 
            on tags0_.tags_id=tag1_.id 
    where
        tags0_.account_id=?
2020-05-17 09:34:12.748 TRACE 8292 --- [io-8080-exec-10] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BIGINT] - [86]
2020-05-17 09:34:12.749 DEBUG 8292 --- [io-8080-exec-10] org.hibernate.SQL                        : 
    select
        tag0_.id as id1_9_,
        tag0_.title as title2_9_ 
    from
        tag tag0_ 
    where
        tag0_.title=?
2020-05-17 09:34:12.749 TRACE 8292 --- [io-8080-exec-10] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [VARCHAR] - [aaaa]
2020-05-17 09:34:12.750 DEBUG 8292 --- [io-8080-exec-10] org.hibernate.SQL                        : 
    delete 
    from
        study_tags 
    where
        study_id=?
2020-05-17 09:34:12.751 TRACE 8292 --- [io-8080-exec-10] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BIGINT] - [87]

문제는 2번째 발생하는 SQL입니다.

제가 생각했을때는 tags와 managers에 관련된 SQL만 발생해야 하는데, 왜 중간에  account_tags 테이블로부터 태그 정보를 얻으려 하는지 모르겠습니다.이 테이블은 settingsController에서 태그 관련 액션시 이용되는 테이블이라고 생각하고 있습니다.

디버그해보니, @CurrentUser시점에서 불러들이는 account의 tags와 zones는 size=0임을 알수 있습니다.

...그렇다고 해도,  getStudyToUPdateTag가 불러졌을때 account_tags가  불려지는 이유를 도무지 알수가 없습니다.
EntityGraphType을 FETCH가 아닌 LOAD타입으로 바꾸면  account_tags관련 SQL이 나오지 않습니다.

제가 코딩을 잘못한  것일까요? 아니면 이 단계에서는 이렇게 나오는게 정상인가요?

PS:
백기선님의 github에서 master브랜치를 디버깅 -> account_tags관련 SQL 안나옴. ->  원인분석 실패...
만일을 대비해, 제 깃헙 링크도 첨부합니다.
https://github.com/yongsoo-kim/studyolle/tree/feature/ph4_study_feature/src/main/java/com/studyolle/studyolle/study