fix: resolve connection pool error

Author: hamlsy

src/main/java/com/example/echoshotx/notification/application/service/SseConnectionManager.java

@@ -8,7 +8,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
@@ -27,40 +26,39 @@ public class SseConnectionManager {
     private static final Long DEFAULT_TIMEOUT = 60L * 1000 * 60; // 60분
     private static final String SSE_EVENT_NAME = "notification";
 
-    // Key: memberId, Value: List of SseEmitters (다중 디바이스 지원)
+    // Key: memberId, Value: SseEmitter (단일 디바이스)
     private final Map<Long, SseEmitter> emitters = new ConcurrentHashMap<>();
 
     public SseEmitter createConnection(Long memberId) {
-        // 기존 연결이 있으면 종료 (새 연결 우선)
-        SseEmitter existingEmitter = emitters.get(memberId);
-        if (existingEmitter != null) {
-            existingEmitter.complete();
-            log.info("Existing SSE connection closed for member: {}", memberId);
-        }
-
         SseEmitter emitter = new SseEmitter(DEFAULT_TIMEOUT);
-        emitters.put(memberId, emitter);
+        
+        // 기존 연결이 있어도 강제 종료하지 않음 - 그냥 새 연결로 교체
+        // 기존 emitter는 자연스럽게 timeout/completion 처리됨
+        SseEmitter oldEmitter = emitters.put(memberId, emitter);
+        if (oldEmitter != null) {
+            log.info("Replacing existing SSE connection for member: {} (old connection will timeout naturally)", memberId);
+        }
 
         log.info("SSE connection created for member: {}", memberId);
 
-        // 연결 완료 시 제거
+        // 연결 완료 시 제거 (현재 활성 emitter인 경우만)
         emitter.onCompletion(
                 () -> {
-                    removeEmitter(memberId);
+                    removeEmitterIfMatch(memberId, emitter);
                     log.info("SSE connection completed for member: {}", memberId);
                 });
 
-        // 타임아웃 시 제거
+        // 타임아웃 시 제거 (현재 활성 emitter인 경우만)
         emitter.onTimeout(
                 () -> {
-                    removeEmitter(memberId);
+                    removeEmitterIfMatch(memberId, emitter);
                     log.warn("SSE connection timeout for member: {}", memberId);
                 });
 
-        // 에러 시 제거
+        // 에러 시 제거 (현재 활성 emitter인 경우만)
         emitter.onError(
                 e -> {
-                    removeEmitter(memberId);
+                    removeEmitterIfMatch(memberId, emitter);
                     log.error("SSE connection error for member: {}, error: {}", memberId, e.getMessage());
                 });
 
@@ -69,7 +67,7 @@ public SseEmitter createConnection(Long memberId) {
             emitter.send(SseEmitter.event().name("connected").data("SSE connection established"));
         } catch (IOException e) {
             log.error("Failed to send initial connection event to member: {}", memberId, e);
-            removeEmitter(memberId);
+            removeEmitterIfMatch(memberId, emitter);
             throw new NotificationHandler(NotificationErrorStatus.SSE_CONNECTION_FAILED);
         }
 
@@ -95,7 +93,7 @@ public boolean sendToMember(Long memberId, Object data) {
             emitter.send(SseEmitter.event().name(SSE_EVENT_NAME).data(data));
             log.info("Notification sent to member: {}", memberId);
             return true;
-        } catch (IOException e) {
+        } catch (IOException | IllegalStateException e) {
             log.error("Failed to send notification to member: {}, removing dead emitter", memberId, e);
             removeEmitter(memberId);
             return false;
@@ -202,6 +200,14 @@ private void removeEmitter(Long memberId) {
         emitters.remove(memberId);
     }
 
+    /**
+     * 특정 Emitter가 현재 활성 emitter인 경우에만 제거.
+     * 이미 새 연결로 교체된 경우 이전 emitter의 콜백이 새 emitter를 제거하지 않도록 함.
+     */
+    private void removeEmitterIfMatch(Long memberId, SseEmitter emitter) {
+        emitters.remove(memberId, emitter);
+    }
+
     /**
      * 모든 연결 해제 (서버 종료 시 사용).
      */

src/main/java/com/example/echoshotx/notification/presentation/controller/TestNotificationController.java

@@ -15,12 +15,14 @@
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.MediaType;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
 /**
  * 테스트용 알림 API 컨트롤러.
@@ -114,4 +116,13 @@ public ApiResponseDto<String> broadcastNotification(
         return ApiResponseDto.onSuccess(
                 String.format("%d개의 연결에 브로드캐스트를 전송했습니다.", totalConnections));
     }
+
+    @Operation(summary = "🔧 테스트용 SSE 구독 (토큰 불필요)", 
+            description = "토큰 없이 memberId를 직접 지정하여 SSE 연결을 테스트합니다. " +
+                    "curl -N 'http://서버주소/test/notifications/subscribe/1' 로 테스트 가능합니다.")
+    @GetMapping(value = "/subscribe/{memberId}", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public SseEmitter testSubscribe(@PathVariable Long memberId) {
+        log.info("🔧 [TEST] SSE connection request for memberId: {}", memberId);
+        return sseConnectionManager.createConnection(memberId);
+    }
 }

src/main/resources/application.yml

@@ -3,6 +3,13 @@ spring:
     active:
       - local
   datasource:
+
+    hikari:
+      maximum-pool-size: 30
+      minimum-idle: 10
+      connection-timeout: 30000
+      idle-timeout: 600000
+      max-lifetime: 1800000
     url: ${SPRING_DATASOURCE_URL}
     username: ${SPRING_DATASOURCE_USERNAME}
     password: ${SPRING_DATASOURCE_PASSWORD}
@@ -15,6 +22,7 @@ spring:
 
 
   jpa:
+    open-in-view: false
     hibernate:
       ddl-auto: update
     defer-datasource-initialization: true