[BE] refactor: /stages/{stageId}/tickets API의 N+1을 해결한다.(#517) (#578)

* refactor: findAllByStageId fetch 조인으로 변경 * refactor: fetch join 메서드 사용하도록 변경 * chore: Inner 조건 명시하도록 변경
woowacourse-teams · Nov 14, 2023 · 1eeb1c7 · 1eeb1c7
1 parent a21401f
commit 1eeb1c7
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Showing 4 changed files with 9 additions and 4 deletions.
diff --git a/backend/src/main/java/com/festago/ticket/application/TicketService.java b/backend/src/main/java/com/festago/ticket/application/TicketService.java
@@ -46,6 +46,6 @@ private Stage findStageById(Long stageId) {
 
     @Transactional(readOnly = true)
     public StageTicketsResponse findStageTickets(Long stageId) {
-        return StageTicketsResponse.from(ticketRepository.findAllByStageId(stageId));
+        return StageTicketsResponse.from(ticketRepository.findAllByStageIdWithFetch(stageId));
     }
 }
diff --git a/backend/src/main/java/com/festago/ticket/repository/TicketRepository.java b/backend/src/main/java/com/festago/ticket/repository/TicketRepository.java
@@ -11,7 +11,12 @@
 
 public interface TicketRepository extends JpaRepository<Ticket, Long> {
 
-    List<Ticket> findAllByStageId(Long stageId);
+    @Query("""
+            SELECT t from Ticket t
+            INNER JOIN FETCH t.ticketAmount
+            WHERE t.stage.id = :stageId
+        """)
+    List<Ticket> findAllByStageIdWithFetch(@Param("stageId") Long stageId);
 
     Optional<Ticket> findByTicketTypeAndStage(TicketType ticketType, Stage stage);
 

diff --git a/backend/src/test/java/com/festago/application/TicketServiceTest.java b/backend/src/test/java/com/festago/application/TicketServiceTest.java
@@ -41,7 +41,7 @@ class TicketServiceTest {
             TicketFixture.ticket().id(1L).ticketType(TicketType.STUDENT).stage(stage).build(),
             TicketFixture.ticket().id(2L).ticketType(TicketType.VISITOR).stage(stage).build()
         );
-        given(ticketRepository.findAllByStageId(stageId))
+        given(ticketRepository.findAllByStageIdWithFetch(stageId))
             .willReturn(tickets);
 
         // when

diff --git a/backend/src/test/java/com/festago/domain/TicketRepositoryTest.java b/backend/src/test/java/com/festago/domain/TicketRepositoryTest.java
@@ -52,7 +52,7 @@ class TicketRepositoryTest {
         ticketRepository.save(TicketFixture.ticket().stage(otherStage).build());
 
         // when
-        List<Ticket> actual = ticketRepository.findAllByStageId(stage.getId());
+        List<Ticket> actual = ticketRepository.findAllByStageIdWithFetch(stage.getId());
 
         // then
         assertThat(actual).hasSize(2);