[BE] refactor: fetchtype을 Lazy로 변경한 후 EntityGraph를 사용해 최적화

backend/src/main/java/reviewme/review/domain/CheckboxAnswer.java

@@ -20,7 +20,7 @@
 @Getter
 public class CheckboxAnswer extends Answer {
 
-    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
+    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
     @JoinColumn(name = "checkbox_answer_id", nullable = false, updatable = false)
     private List<CheckboxAnswerSelectedOption> selectedOptionIds;
 

backend/src/main/java/reviewme/review/domain/Review.java

@@ -37,7 +37,7 @@ public class Review {
     @Column(name = "review_group_id", nullable = false)
     private long reviewGroupId;
 
-    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.PERSIST)
+    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
     @JoinColumn(name = "review_id", nullable = false, updatable = false)
     private List<Answer> answers;
 
@@ -61,6 +61,7 @@ public boolean hasAnsweredQuestion(long questionId) {
         return getAnsweredQuestionIds().contains(questionId);
     }
 
+    // 하위 타입의 구체적인 정보를 알지 못하므로, fetch join할 수 없다..?
     public <T extends Answer> List<T> getAnswersByType(Class<T> clazz) {
         return answers.stream()
                 .filter(clazz::isInstance)

backend/src/main/java/reviewme/review/repository/ReviewRepository.java

@@ -3,19 +3,22 @@
 import java.time.LocalDate;
 import java.util.List;
 import java.util.Optional;
+import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 import reviewme.review.domain.Review;
 
 public interface ReviewRepository extends JpaRepository<Review, Long> {
 
+    @EntityGraph(attributePaths = {"answers"})
     @Query("""
             SELECT r FROM Review r
             WHERE r.reviewGroupId = :reviewGroupId
             ORDER BY r.createdAt DESC
             """)
     List<Review> findAllByGroupId(long reviewGroupId);
 
+    @EntityGraph(attributePaths = {"answers"})
     @Query("""
             SELECT r FROM Review r
             WHERE r.reviewGroupId = :reviewGroupId
@@ -25,6 +28,7 @@ public interface ReviewRepository extends JpaRepository<Review, Long> {
             """)
     List<Review> findByReviewGroupIdWithLimit(long reviewGroupId, Long lastReviewId, int limit);
 
+    @EntityGraph(attributePaths = {"answers"})
     Optional<Review> findByIdAndReviewGroupId(long reviewId, long reviewGroupId);
 
     @Query("""

backend/src/main/java/reviewme/template/domain/Section.java

@@ -34,7 +34,7 @@ public class Section {
     @Enumerated(EnumType.STRING)
     private VisibleType visibleType;
 
-    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
+    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
     @JoinColumn(name = "section_id", nullable = false, updatable = false)
     private List<SectionQuestion> questionIds;
 

backend/src/main/java/reviewme/template/domain/Template.java

@@ -26,7 +26,7 @@ public class Template {
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
-    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
+    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
     @JoinColumn(name = "template_id", nullable = false, updatable = false)
     private List<TemplateSection> sectionIds;
 

backend/src/main/java/reviewme/template/repository/SectionRepository.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 import java.util.Optional;
+import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.stereotype.Repository;
@@ -10,15 +11,16 @@
 @Repository
 public interface SectionRepository extends JpaRepository<Section, Long> {
 
+    @EntityGraph(attributePaths = {"questionIds"})
     @Query("""
             SELECT s FROM Section s
-            JOIN TemplateSection ts
-            ON s.id = ts.sectionId
+            JOIN TemplateSection ts ON s.id = ts.sectionId
             WHERE ts.templateId = :templateId
             ORDER BY s.position ASC
             """)
     List<Section> findAllByTemplateId(long templateId);
 
+    @EntityGraph(attributePaths = {"questionIds"})
     @Query("""
             SELECT s FROM Section s
             JOIN TemplateSection ts ON s.id = ts.sectionId