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fix: 조회 API N+1 쿼리 및 트랜잭션 오버헤드 제거(eliminate N+1 queries and implicit transaction overhead in schedule inquiry API) #39

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Merged
leonroars merged 9 commits into from
Feb 8, 2026
Merged

fix: 조회 API N+1 쿼리 및 트랜잭션 오버헤드 제거(eliminate N+1 queries and implicit transaction overhead in schedule inquiry API) #39

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2bda61c
<fix> Concert 도메인 : 예약 가능 공연 일정 & 공연 정보 조합 도메인 모델 정의
leonroars Feb 8, 2026
1732d9e
<fix> Concert 도메인 : JpaRepository 가 제공하는 findAllById() 명세를 ConcertRep…
leonroars Feb 8, 2026
ea60cb9
<fix> Concert 도메인 : List<ConcertSchedule> -> List<ConcertScheduleWith…
leonroars Feb 8, 2026
98a836a
<fix> Concer 도메인 : Facade method 의 return type - List<ConcertSchedule…
leonroars Feb 8, 2026
972feff
<fix> Concert 도메인 : Controller 수정
leonroars Feb 8, 2026
cb8bcda
<fix> Concert 도메인 : RepositoryImpl 수정
leonroars Feb 8, 2026
f04c27a
<fix> Concert 도메인 : ConcertScheduleWithConcert 모델 도입에 따른 테스트 수정 - 100…
leonroars Feb 8, 2026
272f0ba
<fix> Concert 도메인 : NPE-safe 하도록 filter 로직 추가
leonroars Feb 8, 2026
15b226c
<fix> Concert 도메인 : NPE-safety 위한 filter 로직 추가에 따라, Test 시 Concert 객체…
leonroars Feb 8, 2026
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5 changes: 3 additions & 2 deletions ...in/java/com/slam/concertreservation/application/facade/ConcertReservationApplication.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

import com.slam.concertreservation.domain.concert.model.Concert;
import com.slam.concertreservation.domain.concert.model.ConcertSchedule;
import com.slam.concertreservation.domain.concert.model.ConcertScheduleWithConcert;
import com.slam.concertreservation.domain.concert.model.Seat;
import com.slam.concertreservation.domain.concert.service.ConcertService;
import com.slam.concertreservation.domain.point.model.PointHistory;
Expand Down Expand Up @@ -116,8 +117,8 @@ public ConcertSchedule getConcertSchedule(Long concertScheduleId) {
*
* @return
*/
public List<ConcertSchedule> getAvailableConcertSchedules() {
return concertService.getAvailableConcertSchedule(LocalDateTime.now());
public List<ConcertScheduleWithConcert> getAvailableConcertSchedulesWithConcert() {
return concertService.getAvailableConcertScheduleWithConcert(LocalDateTime.now());
}

/**
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11 changes: 11 additions & 0 deletions ...ain/java/com/slam/concertreservation/domain/concert/model/ConcertScheduleWithConcert.java
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@@ -0,0 +1,11 @@
package com.slam.concertreservation.domain.concert.model;

/**
* 예약 가능 공연 일정 조회 시 반환되는 공연 일정 & 공연 정보 조합 모델
* @param concertSchedule
* @param concert
*/
public record ConcertScheduleWithConcert(
ConcertSchedule concertSchedule,
Concert concert
) {}
3 changes: 3 additions & 0 deletions src/main/java/com/slam/concertreservation/domain/concert/repository/ConcertRepository.java
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@@ -1,11 +1,14 @@
package com.slam.concertreservation.domain.concert.repository;

import com.slam.concertreservation.domain.concert.model.Concert;
import java.util.List;
import java.util.Optional;

public interface ConcertRepository {

Concert save(Concert concert);

Optional<Concert> findById(Long id);

List<Concert> findAllById(List<Long> ids);
}
35 changes: 27 additions & 8 deletions src/main/java/com/slam/concertreservation/domain/concert/service/ConcertService.java
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Expand Up @@ -3,6 +3,7 @@
import com.slam.concertreservation.common.error.ErrorCode;
import com.slam.concertreservation.domain.concert.model.Concert;
import com.slam.concertreservation.domain.concert.model.ConcertSchedule;
import com.slam.concertreservation.domain.concert.model.ConcertScheduleWithConcert;
import com.slam.concertreservation.domain.concert.model.Seat;
import com.slam.concertreservation.domain.concert.repository.ConcertRepository;
import com.slam.concertreservation.domain.concert.repository.ConcertScheduleRepository;
Expand All @@ -11,6 +12,7 @@
import com.slam.concertreservation.infrastructure.persistence.redis.locking.RedissonDistributedLock;
import java.time.LocalDateTime;
import java.util.List;
import java.util.Map;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationEventPublisher;
Expand Down Expand Up @@ -265,14 +267,31 @@ public List<Seat> getAvailableSeatsOfConcertSchedule(Long concertScheduleId) {
return availableSeats;
}

/**
* 예약 가능 공연 일정 목록 조회.
*
* @param presentDateTime
* @return
*/
public List<ConcertSchedule> getAvailableConcertSchedule(LocalDateTime presentDateTime) {
return concertScheduleRepository.findAllAvailable(presentDateTime);
@Transactional(readOnly = true)
public List<ConcertScheduleWithConcert> getAvailableConcertScheduleWithConcert(LocalDateTime presentDateTime) {

// 예약 가능한 공연 일정 조회
List<ConcertSchedule> schedules = concertScheduleRepository.findAllAvailable(presentDateTime);

// 예약 가능한 공연 ID 목록 추출
List<Long> concertIds = schedules.stream()
.map(ConcertSchedule::getConcertId)
.distinct()
.toList();

// 공연 ID 목록으로 공연 조회
Map<Long, Concert> concerts = concertRepository.findAllById(concertIds)
.stream()
.collect(
java.util.stream.Collectors.toMap(Concert::getId, concert -> concert));

// ConcertSchedule과 Concert를 결합하여 ConcertScheduleWithConcert 생성
return schedules.stream()
.filter(schedule -> concerts.get(schedule.getConcertId()) != null)
.map(schedule -> new ConcertScheduleWithConcert(
schedule,
concerts.get(schedule.getConcertId())))
.toList();
Comment thread
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}

/**
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9 changes: 9 additions & 0 deletions ...om/slam/concertreservation/infrastructure/persistence/jpa/impl/ConcertRepositoryImpl.java
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Expand Up @@ -4,6 +4,7 @@
import com.slam.concertreservation.domain.concert.repository.ConcertRepository;
import com.slam.concertreservation.infrastructure.persistence.jpa.ConcertJpaRepository;
import com.slam.concertreservation.infrastructure.persistence.jpa.entities.ConcertJpaEntity;
import java.util.List;
import java.util.Optional;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Repository;
Expand All @@ -25,4 +26,12 @@ public Optional<Concert> findById(Long concertId) {
return concertJpaRepository.findById(concertId)
.map(ConcertJpaEntity::toDomain);
}

@Override
public List<Concert> findAllById(List<Long> ids) {
return concertJpaRepository.findAllById(ids)
.stream()
.map(ConcertJpaEntity::toDomain)
.toList();
}
Comment on lines +30 to +36

@coderabbitai coderabbitai Bot Feb 8, 2026

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⚠️ Potential issue | 🔴 Critical

🧩 Analysis chain

🏁 Script executed:

rg -n -A 30 'getAvailableConcertScheduleWithConcert' --type=java -g '!*Test*'

Repository: leonroars/slam

Length of output: 7769

🏁 Script executed:

rg -n 'class ConcertScheduleWithConcert' --type=java -A 15

Repository: leonroars/slam

Length of output: 40

🏁 Script executed:

rg -n 'ConcertScheduleWithConcert' --type=java | head -20

Repository: leonroars/slam

Length of output: 2909

🏁 Script executed:

cat -n src/main/java/com/slam/concertreservation/domain/concert/model/ConcertScheduleWithConcert.java

Repository: leonroars/slam

Length of output: 402

🏁 Script executed:

rg -n -B 5 -A 10 'getAvailableConcertSchedulesWithConcert' src/main/java/com/slam/concertreservation/interfaces/ConcertReservationController.java

Repository: leonroars/slam

Length of output: 694

🏁 Script executed:

rg -n -B 3 -A 15 'class ConcertScheduleResponse' --type=java -g '!*Test*' | head -50

Repository: leonroars/slam

Length of output: 2441

findAllById doesn't guarantee all requested IDs are found — will cause NullPointerException.

Spring Data JPA's findAllById returns only entities that exist. If a ConcertSchedule references a concertId that doesn't exist in the DB, concerts.get(schedule.getConcertId()) returns null. This null Concert is then passed to ConcertScheduleResponse.from(schedule, concert), which calls concert.getName() and concert.getArtist() (lines 25-26 in ConcertScheduleResponse), causing a NullPointerException at runtime.

Either validate that all Concert IDs exist before creating results, or filter out schedules with missing concerts.

🤖 Prompt for AI Agents 
In
`@src/main/java/com/slam/concertreservation/infrastructure/persistence/jpa/impl/ConcertRepositoryImpl.java`
around lines 30 - 36, The current findAllById implementation
(ConcertRepositoryImpl.findAllById) can return fewer Concerts than requested
which leads to nulls when matching schedules; update the code that builds
schedule responses to either (a) validate that the returned list from
findAllById contains all requested IDs (compare size or missing IDs) and throw a
clear exception before calling ConcertScheduleResponse.from, or (b) filter out
ConcertSchedule entries that reference missing concerts by checking the map
built from
concertJpaRepository.findAllById(ids).stream().map(ConcertJpaEntity::toDomain)
for null/missing keys and skipping those schedules before invoking
ConcertScheduleResponse.from(schedule, concert); choose one approach and apply
it where ConcertScheduleResponse.from is called to prevent NullPointerException.

}
14 changes: 6 additions & 8 deletions src/main/java/com/slam/concertreservation/interfaces/ConcertReservationController.java
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Expand Up @@ -5,6 +5,7 @@
import com.slam.concertreservation.component.idempotency.Idempotent;
import com.slam.concertreservation.domain.concert.model.Concert;
import com.slam.concertreservation.domain.concert.model.ConcertSchedule;
import com.slam.concertreservation.domain.concert.model.ConcertScheduleWithConcert;
import com.slam.concertreservation.domain.concert.model.Seat;
import com.slam.concertreservation.domain.point.model.UserPointBalance;
import com.slam.concertreservation.domain.queue.model.Token;
Expand Down Expand Up @@ -118,14 +119,11 @@ public ResponseEntity<ConcertScheduleResponse> registerConcertSchedule(
*/
@GetMapping("/concerts/schedules/available")
public ResponseEntity<List<ConcertScheduleResponse>> getAvailableConcertSchedules() {
List<ConcertSchedule> schedules = reservationApp.getAvailableConcertSchedules();
List<ConcertScheduleResponse> responses = schedules.stream()
.map(schedule -> {
Concert concert = reservationApp.getConcert(schedule.getConcertId());
return ConcertScheduleResponse.from(schedule, concert);
})
.toList();
return ResponseEntity.ok(responses);
List<ConcertScheduleWithConcert> schedules = reservationApp.getAvailableConcertSchedulesWithConcert();

return ResponseEntity.ok(schedules.stream()
.map(r -> ConcertScheduleResponse.from(r.concertSchedule(), r.concert()))
.toList());
}

/**
Expand Down
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