Refactor: 웨이팅 등록 기능 성능 개선

nowait-app-user-api/src/main/java/com/nowait/applicationuser/exception/GlobalExceptionHandler.java

@@ -215,7 +215,7 @@ public ErrorResponse reservationNotFoundException(ReservationNotFoundException e
 		return new ErrorResponse(e.getMessage(), NOTFOUND_RESERVATION.getCode());
 	}
 
-	@ResponseStatus(BAD_REQUEST)
+	@ResponseStatus(CONFLICT)
 	@ExceptionHandler(DuplicateReservationException.class)
 	public ErrorResponse duplicateReservationException(DuplicateReservationException e, WebRequest request) {
 		alarm(e, request);

nowait-app-user-api/src/main/java/com/nowait/applicationuser/reservation/dto/WaitingSnapshot.java

@@ -0,0 +1,13 @@
+package com.nowait.applicationuser.reservation.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class WaitingSnapshot {
+	private final Long rank;
+	private final Integer partySize;
+	private final String reservationId;
+	private final boolean isNew;
+}

nowait-app-user-api/src/main/java/com/nowait/applicationuser/reservation/repository/WaitingUserRedisRepository.java

@@ -18,8 +18,10 @@
 import org.springframework.data.redis.core.RedisCallback;
 import org.springframework.data.redis.core.ScanOptions;
 import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.script.DefaultRedisScript;
 import org.springframework.stereotype.Repository;
 
+import com.nowait.applicationuser.reservation.dto.WaitingSnapshot;
 import com.nowait.domaincoreredis.common.util.RedisKeyUtils;
 
 import lombok.RequiredArgsConstructor;
@@ -28,6 +30,52 @@
 @RequiredArgsConstructor
 public class WaitingUserRedisRepository {
 	private final StringRedisTemplate redisTemplate;
+	private static final String ADD_WAITING_LUA = """
+		-- KEYS
+		-- 1: queueKey
+		-- 2: partyKey
+		-- 3: statusKey
+		-- 4: numberMapKey
+		-- 5: dailySeqKey
+
+		-- ARGV
+		-- 1: userId
+		-- 2: timestamp (ms)
+		-- 3: partySize
+		-- 4: today (YYYYMMDD)
+		-- 5: storeId
+		-- 6: ttlMillis
+
+		-- 1) ZADD NX
+		local added = redis.call('ZADD', KEYS[1], 'NX', ARGV[2], ARGV[1])
+
+		local isNew = 0
+		local reservationId
+
+		if added == 1 then
+			isNew = 1
+			local seq = redis.call('INCR', KEYS[5])
+			local seqStr = string.format('%04d', seq)
+			reservationId = ARGV[5] .. '-' .. ARGV[4] .. '-' .. seqStr
+
+			redis.call('HSET', KEYS[4], ARGV[1], reservationId)
+			redis.call('HSET', KEYS[2], ARGV[1], ARGV[3])
+			redis.call('HSET', KEYS[3], ARGV[1], 'WAITING')
+		else
+			reservationId = redis.call('HGET', KEYS[4], ARGV[1])
+		end
+
+		local rank = redis.call('ZRANK', KEYS[1], ARGV[1])
+
+		-- TTL: 키가 처음 생성된 경우만
+		if redis.call('PTTL', KEYS[1]) == -1 then
+			for i = 1, #KEYS do
+				redis.call('PEXPIRE', KEYS[i], ARGV[6])
+			end
+		end
+
+		return {isNew, rank, ARGV[3], reservationId}          
+		""";
 
 	// 중복 등록 방지: 이미 있으면 추가X
 	// 특정 주점에 대한 예약 등록
@@ -68,6 +116,61 @@ public String addToWaitingQueue(Long storeId, String userId, Integer partySize,
 		return reservationId;
 	}
 
+	// 루아 스크립트 사용
+	public WaitingSnapshot addToWaitingQueueLua(
+		Long storeId,
+		String userId,
+		Integer partySize,
+		long ts,
+		Duration ttl
+	) {
+		String queueKey = RedisKeyUtils.buildWaitingKeyPrefix() + storeId;
+		String partyKey = RedisKeyUtils.buildWaitingPartySizeKeyPrefix() + storeId;
+		String statusKey = RedisKeyUtils.buildWaitingStatusKeyPrefix() + storeId;
+		String numberMapKey = RedisKeyUtils.buildReservationNumberKey(storeId);
+
+		String today = LocalDate.now().format(DateTimeFormatter.BASIC_ISO_DATE);
+		String dailySeqKey = RedisKeyUtils.buildReservationSeqKey(storeId) + ":" + today;
+
+		List<String> keys = List.of(
+			queueKey,
+			partyKey,
+			statusKey,
+			numberMapKey,
+			dailySeqKey
+		);
+
+		Object result = redisTemplate.execute(
+			new DefaultRedisScript<>(ADD_WAITING_LUA, List.class),
+			keys,
+			userId,
+			String.valueOf(ts),
+			String.valueOf(partySize),
+			today,
+			String.valueOf(storeId),
+			String.valueOf(ttl.toMillis())
+		);
+
+		if (result == null) return null;
+
+		@SuppressWarnings("unchecked")
+		List<Object> response = (List<Object>) result;
+		if (response == null || response.size() < 4) return null;
+
+		boolean isNew = ((Long) response.get(0)) == 1L;
+		Long rank = response.get(1) == null ? null : (Long) response.get(1);
+		Integer ps = response.get(2) == null ? null : Integer.valueOf(response.get(2).toString());
+		String reservationId = response.get(3) == null ? null : response.get(3).toString();
+
+		if (!isNew) {
+			// 중복 등록: Redis 재조회 없음
+			return new WaitingSnapshot(rank, ps, reservationId, false);
+		}
+
+		// 신규 등록
+		return new WaitingSnapshot(rank, ps, reservationId, true);
+	}
+
 	// 예약한 사람이 등록한 동반인원(partySize) 조회
 	public Integer getPartySize(Long storeId, String userId) {
 		String partyKey = RedisKeyUtils.buildWaitingPartySizeKeyPrefix() + storeId;
@@ -214,6 +317,52 @@ public String GenerateReservationNumber(String seqKey, Long storeId) {
 
 		return reservationId;
 	}
+
+	public WaitingSnapshot getWaitingSnapshot(Long storeId, String userId) {
+		String queueKey = RedisKeyUtils.buildWaitingKeyPrefix() + storeId;
+		String partyKey = RedisKeyUtils.buildWaitingPartySizeKeyPrefix() + storeId;
+		String numberMapKey = RedisKeyUtils.buildReservationNumberKey(storeId);
+
+		List<Object> results = redisTemplate.executePipelined((RedisCallback<Object>) conn -> {
+			byte[] qk = redisTemplate.getStringSerializer().serialize(queueKey);
+			byte[] pk = redisTemplate.getStringSerializer().serialize(partyKey);
+			byte[] nk = redisTemplate.getStringSerializer().serialize(numberMapKey);
+			byte[] uid = redisTemplate.getStringSerializer().serialize(userId);
+
+			conn.zRank(qk, uid);
+			conn.hGet(pk, uid);
+			conn.hGet(nk, uid);
+			return null;
+		});
+
+		if (results == null || results.size() < 3) {
+			return new WaitingSnapshot(null, null, null, false);
+		}
+
+		// 1) rank
+		Long rank = (results.get(0) instanceof Long r) ? r : null;
+
+		// 2) partySize
+		Integer partySize = null;
+		Object psObj = results.get(1);
+		if (psObj instanceof String s) {
+			partySize = Integer.valueOf(s);
+		} else if (psObj instanceof byte[] b) {
+			String deserialized = redisTemplate.getStringSerializer().deserialize(b);
+			partySize = deserialized != null ? Integer.valueOf(deserialized) : null;
+		}
+
+		// 3) reservationId
+		String reservationId = null;
+		Object ridObj = results.get(2);
+		if (ridObj instanceof String s) {
+			reservationId = s;
+		} else if (ridObj instanceof byte[] b) {
+			reservationId = redisTemplate.getStringSerializer().deserialize(b);
+		}
+
+		return new WaitingSnapshot(rank, partySize, reservationId, false);
+	}
 }
 
 

nowait-app-user-api/src/main/java/com/nowait/applicationuser/reservation/service/ReservationService.java

@@ -10,6 +10,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.UUID;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -22,6 +23,7 @@
 import com.nowait.applicationuser.reservation.dto.ReservationCreateRequestDto;
 import com.nowait.applicationuser.reservation.dto.ReservationCreateResponseDto;
 import com.nowait.applicationuser.reservation.dto.WaitingResponseDto;
+import com.nowait.applicationuser.reservation.dto.WaitingSnapshot;
 import com.nowait.applicationuser.reservation.repository.WaitingUserRedisRepository;
 import com.nowait.common.enums.ReservationStatus;
 import com.nowait.common.enums.Role;
@@ -118,20 +120,8 @@ public WaitingResponseDto registerWaiting(Long storeId, CustomOAuth2User princip
 		String userId = user.getId().toString();
 		Duration ttlTo3am = waitingUserRedisRepository.calculateTTLUntilNext03AM();
 
-		// 1) 이미 해당 store에 대기 중이면 임대 없이 현재 상태 반환 (중복 요청 허용)
-		if (Boolean.TRUE.equals(waitingUserRedisRepository.isUserWaiting(storeId, userId))) {
-			Long rank = waitingUserRedisRepository.getRank(storeId, userId);
-			Integer ps = waitingUserRedisRepository.getPartySize(storeId, userId);
-			String reservationId = waitingUserRedisRepository.getReservationId(storeId, userId);
-			return WaitingResponseDto.builder()
-				.reservationNumber(reservationId)
-				.rank(rank == null ? -1 : rank.intValue() + 1)
-				.partySize(ps == null ? 0 : ps)
-				.build();
-		}
-
 		// 1) 임대 획득
-		String token = java.util.UUID.randomUUID().toString();
+		String token = UUID.randomUUID().toString();
 		int attempts = 0;
 		while (true) {
 			boolean ok = waitingPermitLuaRepository.acquireLease(userId, token, System.currentTimeMillis(), LEASE_MS,
@@ -146,28 +136,57 @@ public WaitingResponseDto registerWaiting(Long storeId, CustomOAuth2User princip
 			}
 		}
 
-		String reservationId = null;
+		// 2) 임대 획득 후 중복 체크
+		WaitingSnapshot existingSnapshot = waitingUserRedisRepository.getWaitingSnapshot(storeId, userId);
+		if (existingSnapshot != null &&  existingSnapshot.getRank() != null) {
+			waitingPermitLuaRepository.releaseLease(userId, token);
+			throw new DuplicateReservationException();
+		}
+
+		WaitingSnapshot snapshot = null;
 		try {
 			// 2) 스토어 큐 등록(기존 메서드 그대로)
 			long ts = System.currentTimeMillis();
-			reservationId = waitingUserRedisRepository.addToWaitingQueue(storeId, userId, dto.getPartySize(), ts);
-			if (reservationId == null)
+
+			snapshot = waitingUserRedisRepository.addToWaitingQueueLua(
+				storeId, userId, dto.getPartySize(), ts, ttlTo3am
+			);
+
+			if (snapshot == null || snapshot.getReservationId() == null)
 				throw new ReservationNumberIssueFailException();
 
-			// 3) 확정(holding→active)
-			waitingPermitLuaRepository.finalizeActive(userId, token, String.valueOf(storeId), reservationId, ttlTo3am);
+
+			if (snapshot.isNew()) {
+				waitingPermitLuaRepository.finalizeActive(
+					userId,
+					token,
+					String.valueOf(storeId),
+					snapshot.getReservationId(),
+					ttlTo3am
+				);
+			} else {
+				// Lua 스크립트 중복 감지 케이스
+				waitingPermitLuaRepository.releaseLease(userId, token);
+				throw new DuplicateReservationException();
+			}
+
+			// 3) 확정(holding → active)
+			WaitingSnapshot after = waitingUserRedisRepository.getWaitingSnapshot(storeId, userId);
+			if (after == null)
+				throw new ReservationNumberIssueFailException();
 
 			// 4) 응답
-			Long rank = waitingUserRedisRepository.getRank(storeId, userId);
 			return WaitingResponseDto.builder()
-				.reservationNumber(reservationId)
-				.rank(rank == null ? -1 : rank.intValue() + 1)
-				.partySize(dto.getPartySize() == null ? 0 : dto.getPartySize())
+				.reservationNumber(after.getReservationId())
+				.rank(after.getRank() == null ? -1 : after.getRank().intValue() + 1)
+				.partySize(after.getPartySize() == null ? 0 : after.getPartySize())
 				.build();
 
 		} catch (RuntimeException e) {
 			// 실패 시 임대 반납
-			waitingPermitLuaRepository.releaseLease(userId, token);
+			if (snapshot == null || (snapshot.isNew())) {
+				waitingPermitLuaRepository.releaseLease(userId, token);
+			}
 			throw e;
 		}
 	}

nowait-domain/domain-redis/src/main/java/com/nowait/domaincoreredis/common/util/RedisKeyUtils.java

@@ -80,6 +80,8 @@ public static String buildReservationUserKey(Long storeId) {
 		return String.format("reservation:user:%d", storeId);
 	}
 
+	public static String buildUserLeaseCountKey(String userId) { return "userID:{" + userId + "}:lease:cnt"; }
+
 	/**
 	 * 대기 호출 시각(hash)에 사용할 키 접두사
 	 */