refactor: n+1 발생하는 쿼리 개선

woowacourse-teams · Sep 17, 2024 · 8161b67 · 8161b67
1 parent 8ade7dc
commit 8161b67
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Showing 4 changed files with 21 additions and 5 deletions.
diff --git a/backend/src/main/java/develup/application/discussion/DiscussionService.java b/backend/src/main/java/develup/application/discussion/DiscussionService.java
@@ -37,7 +37,7 @@ public DiscussionService(
     }
 
     public List<SummarizedDiscussionResponse> getSummaries(String mission, String hashTagName) {
-        return discussionRepository.findByMissionAndHashTagName(mission, hashTagName).stream()
+        return discussionRepository.findAllByMissionAndHashTagName(mission, hashTagName).stream()
                 .map(SummarizedDiscussionResponse::from)
                 .toList();
     }

diff --git a/backend/src/main/java/develup/domain/discussion/DiscussionRepository.java b/backend/src/main/java/develup/domain/discussion/DiscussionRepository.java
@@ -24,10 +24,19 @@ public interface DiscussionRepository extends JpaRepository<Discussion, Long> {
                     AND sht.name = :hashTag
                 ))
             """)
-    List<Discussion> findByMissionAndHashTagName(
+    List<Discussion> findAllByMissionAndHashTagName(
             @Param("mission") String mission,
             @Param("hashTag") String hashTagName
     );
 
+    @Query("""
+            SELECT d
+            FROM Discussion d
+            JOIN FETCH d.mission m
+            JOIN FETCH d.member me
+            JOIN FETCH d.discussionHashTags.hashTags dhts
+            JOIN FETCH dhts.hashTag ht
+            WHERE me.id = :memberId
+            """)
     List<Discussion> findAllByMember_Id(Long memberId);
 }
diff --git a/backend/src/test/java/develup/application/discussion/DiscussionServiceTest.java b/backend/src/test/java/develup/application/discussion/DiscussionServiceTest.java
@@ -171,12 +171,15 @@ void createWithUnknownHashTag() {
 
     @Test
     @DisplayName("나의 디스커션 리스트를 조회한다.")
+    @Transactional
     void getDiscussionsByMemberId() {
         Member member = memberRepository.save(MemberTestData.defaultMember().withId(1L).build());
         Mission mission = missionRepository.save(MissionTestData.defaultMission().build());
+        HashTag hashTag = hashTagRepository.save(HashTagTestData.defaultHashTag().build());
         Discussion discussion = DiscussionTestData.defaultDiscussion()
                 .withMember(member)
                 .withMission(mission)
+                .withHashTags(List.of(hashTag))
                 .build();
 
         discussionRepository.save(discussion);

diff --git a/backend/src/test/java/develup/domain/discussion/DiscussionRepositoryTest.java b/backend/src/test/java/develup/domain/discussion/DiscussionRepositoryTest.java
@@ -45,7 +45,7 @@ void findAllDiscussion() {
         createDiscussion(mission, hashTag);
         createDiscussion(mission, hashTag);
 
-        List<Discussion> actual = discussionRepository.findByMissionAndHashTagName(
+        List<Discussion> actual = discussionRepository.findAllByMissionAndHashTagName(
                 "all",
                 "all"
         );
@@ -63,7 +63,7 @@ void findAllDiscussionByHashTag() {
         createDiscussion(mission, hashTag1);
         createDiscussion(mission, hashTag2);
 
-        List<Discussion> discussions = discussionRepository.findByMissionAndHashTagName(
+        List<Discussion> discussions = discussionRepository.findAllByMissionAndHashTagName(
                 "all",
                 "JAVA"
         );
@@ -85,7 +85,7 @@ void findAllDiscussionByMission() {
         createDiscussion(mission1, hashTag);
         createDiscussion(mission2, hashTag);
 
-        List<Discussion> discussions = discussionRepository.findByMissionAndHashTagName(
+        List<Discussion> discussions = discussionRepository.findAllByMissionAndHashTagName(
                 "루터회관 흡연단속",
                 "all"
         );
@@ -97,18 +97,22 @@ void findAllDiscussionByMission() {
 
     @Test
     @DisplayName("멤버 식별자를 통해 디스커션을 조회한다.")
+    @Transactional
     void findByMember_Id() {
         Member member1 = memberRepository.save(MemberTestData.defaultMember().withId(1L).build());
         Member member2 = memberRepository.save(MemberTestData.defaultMember().withId(2L).build());
         Mission mission = missionRepository.save(MissionTestData.defaultMission().build());
+        HashTag hashTag = hashTagRepository.save(HashTagTestData.defaultHashTag().build());
 
         Discussion discussionByMember1 = DiscussionTestData.defaultDiscussion()
                 .withMission(mission)
                 .withMember(member1)
+                .withHashTags(List.of(hashTag))
                 .build();
         Discussion discussionByMember2 = DiscussionTestData.defaultDiscussion()
                 .withMission(mission)
                 .withMember(member2)
+                .withHashTags(List.of(hashTag))
                 .build();
 
         discussionRepository.save(discussionByMember1);