fix : 랭킹 카테고리 조회 메타데이터 사용 , 랭킹 캐싱 ttl 11분으로 교체 (#159)

Author: cba700

src/main/java/com/threestar/trainus/domain/ranking/repository/RankingRepository.java

@@ -31,22 +31,25 @@ ORDER BY (
 	List<RankingData> findTopRankings();
 
 	@Query("""
-		SELECT r.reviewee.id as userId,
-			r.reviewee.nickname as userNickname,
-			CAST(COUNT(r.reviewId) AS INTEGER) as reviewCount,
-			CAST(AVG(r.rating) AS DOUBLE) as rating,
-			p.profileImage as profileImage
-		FROM Review r
-		JOIN r.lesson l
-		JOIN r.reviewee u
+		SELECT pm.user.id as userId,
+		    pm.user.nickname as userNickname,
+		    pm.reviewCount as reviewCount,
+		    pm.rating as rating,
+		    p.profileImage as profileImage
+		FROM ProfileMetadata pm
+		JOIN pm.user u
 		LEFT JOIN Profile p ON p.user = u
-		WHERE l.category = :category
-		AND r.deletedAt IS NULL
-		GROUP BY r.reviewee.id, r.reviewee.nickname, p.profileImage
-		HAVING COUNT(r.reviewId) >= 5
+		WHERE pm.reviewCount >= 5
+		AND EXISTS (
+		    SELECT 1 FROM Review r 
+		    JOIN r.lesson l 
+		    WHERE r.reviewee = u 
+		    AND l.category = :category 
+		    AND r.deletedAt IS NULL
+		)
 		ORDER BY (
-			(AVG(r.rating) / 5.0) * 0.5 +
-			(LEAST(COUNT(r.reviewId), 100) / 100.0) * 0.5
+		    (pm.rating / 5.0) * 0.5 +
+		    (LEAST(pm.reviewCount, 100) / 100.0) * 0.5
 		) DESC
 		LIMIT 10
 		""")

src/main/java/com/threestar/trainus/domain/ranking/service/RankingService.java

@@ -90,7 +90,7 @@ private List<RankingResponseDto> calculateRankings(Category category) {
 	private void saveToRedis(List<RankingResponseDto> rankings, String cacheKey) {
 		try {
 			String json = objectMapper.writeValueAsString(rankings);
-			redisTemplate.opsForValue().set(cacheKey, json, Duration.ofHours(24));
+			redisTemplate.opsForValue().set(cacheKey, json, Duration.ofMinutes(11));
 		} catch (Exception e) {
 			log.warn("Redis 저장 실패: {}", e.getMessage());
 		}