홈 크리에이터 랭킹 팔로우 조회 최적화

홈 API의 크리에이터 랭킹 응답에서 팔로우 여부를 일괄 조회로 계산한다.

src/main/kotlin/kr/co/vividnext/sodalive/api/home/HomeService.kt

@@ -82,17 +82,19 @@ class HomeService(
             timezone = timezone
         )
 
-        val creatorRanking = rankingRepository
+        val creatorRankingMembers = rankingRepository.getCreatorRankings(memberId = memberId)
-            .getCreatorRankings(memberId = memberId)
+        val creatorRankingIds = creatorRankingMembers.mapNotNull { it.id }
-            .map {
+        val followedCreatorIds = if (memberId != null) {
-                val followerCount = explorerQueryRepository.getNotificationUserIds(it.id!!).size
+            explorerQueryRepository.getFollowedCreatorIds(creatorRankingIds, memberId)
-                val follow = if (memberId != null) {
-                    explorerQueryRepository.isFollow(it.id!!, memberId = memberId)
         } else {
-                    false
+            emptySet()
         }
 
-                it.toExplorerSectionCreator(imageHost, follow, followerCount = followerCount)
+        val creatorRanking = creatorRankingMembers.map { creator ->
+            val creatorId = creator.id!!
+            val follow = memberId != null && followedCreatorIds.contains(creatorId)
+
+            creator.toExplorerSectionCreator(imageHost, follow)
         }
 
         val latestContentThemeList = contentThemeService.getActiveThemeOfContent(

src/main/kotlin/kr/co/vividnext/sodalive/explorer/ExplorerQueryRepository.kt

@@ -637,6 +637,23 @@ class ExplorerQueryRepository(
             .fetchOne() ?: false
     }
 
+    fun getFollowedCreatorIds(creatorIds: List<Long>, memberId: Long): Set<Long> {
+        if (creatorIds.isEmpty()) {
+            return emptySet()
+        }
+
+        return queryFactory
+            .select(creatorFollowing.creator.id)
+            .from(creatorFollowing)
+            .where(
+                creatorFollowing.isActive.isTrue
+                    .and(creatorFollowing.creator.id.`in`(creatorIds))
+                    .and(creatorFollowing.member.id.eq(memberId))
+            )
+            .fetch()
+            .toSet()
+    }
+
     fun getCreatorCheers(cheersId: Long): CreatorCheers? {
         return queryFactory
             .selectFrom(creatorCheers)