diff --git a/application/src/main/java/org/thingsboard/server/service/subscription/TbAlarmDataSubCtx.java b/application/src/main/java/org/thingsboard/server/service/subscription/TbAlarmDataSubCtx.java index 893d7ed91c..c3343effb5 100644 --- a/application/src/main/java/org/thingsboard/server/service/subscription/TbAlarmDataSubCtx.java +++ b/application/src/main/java/org/thingsboard/server/service/subscription/TbAlarmDataSubCtx.java @@ -177,7 +177,9 @@ public class TbAlarmDataSubCtx extends TbAbstractDataSubCtx { alarm.getLatest().computeIfAbsent(keyType, tmp -> new HashMap<>()).putAll(latestUpdate); return alarm; }).collect(Collectors.toList()); - wsService.sendWsMsg(sessionId, new AlarmDataUpdate(cmdId, null, update, maxEntitiesPerAlarmSubscription, data.getTotalElements())); + if (!update.isEmpty()) { + wsService.sendWsMsg(sessionId, new AlarmDataUpdate(cmdId, null, update, maxEntitiesPerAlarmSubscription, data.getTotalElements())); + } } else { log.trace("[{}][{}][{}][{}] Received stale subscription update: {}", sessionId, cmdId, subscriptionUpdate.getSubscriptionId(), keyType, subscriptionUpdate); }