diff --git a/Readme.md b/Readme.md
index dfe89ab..c06cc5b 100644
--- a/Readme.md
+++ b/Readme.md
@@ -6,3 +6,5 @@
 
 MQTT 服务器管理员账号 ：admin/[admin@emqx]
 
+MQTT 服务器安装路径 : C:/Program File (x86)/emqx-5.3.2-windows-amd64
+
diff --git a/app.db b/app.db
index f30aaad..1236bce 100644
Binary files a/app.db and b/app.db differ
diff --git a/src/main/java/com/iflytop/digester/underframework/dao/model/UfMdbNotification.java b/src/main/java/com/iflytop/digester/underframework/dao/model/UfMdbNotification.java
index 48ff79a..318167f 100644
--- a/src/main/java/com/iflytop/digester/underframework/dao/model/UfMdbNotification.java
+++ b/src/main/java/com/iflytop/digester/underframework/dao/model/UfMdbNotification.java
@@ -2,9 +2,9 @@ package com.iflytop.digester.underframework.dao.model;
 import com.iflytop.digester.underframework.dao.record.UfActiveRecord;
 import com.iflytop.digester.underframework.dao.record.UfActiveRecordField;
 import com.iflytop.digester.underframework.util.UfJsonHelper;
-
+import org.springframework.util.DigestUtils;
+import java.text.SimpleDateFormat;
 import java.util.Map;
-
 public class UfMdbNotification extends UfActiveRecord {
     @UfActiveRecordField
     public String type;
@@ -12,66 +12,48 @@ public class UfMdbNotification extends UfActiveRecord {
     public String data;
     @UfActiveRecordField
     public String status;
+    @UfActiveRecordField
+    public String hash;
+    @UfActiveRecordField
+    public String time;
 
     // get table name
     public static String getTableName() {
         return "app_notifications";
     }
-//
-//    // notify action
-//    public static void taskAction(DiTask task, String action ) {
-//        DiMdbNotification.taskAction(task, action, "");
-//    }
-//
-//    // notify action
-//    public static void taskAction( DiTask task, String action, Object data ) {
-//        Map<String, Object> notifyData = Map.of(
-//            "action", action,
-//            "data", data,
-//            "task", task.getUUID()
-//        );
-//        var notification = new DiMdbNotification();
-//        notification.type = "task-action";
-//        notification.data = DiJsonHelper.objectToJson(notifyData);
-//        notification.status = "new";
-//        notification.save();
-//    }
-//
-//    // notify error
-//    public static void taskError( DiTask task, String error ) {
-//        var notification = new DiMdbNotification();
-//        notification.type = "task-error";
-//        notification.data = error;
-//        notification.status = "new";
-//        notification.save();
-//    }
-//
-//    // notify warning
-//    public static void warning( String message ) {
-//        var notification = new DiMdbNotification();
-//        notification.type = "warning";
-//        notification.data = message;
-//        notification.status = "new";
-//        notification.save();
-//    }
 
-    // notify error
-    public static void error( String message, Object ... args ) {
-        var notification = new UfMdbNotification();
-        notification.type = "error";
-        notification.data = String.format(message, args);
+    // create notification
+    private static void createNotification( String type, String data ) {
+        var hash = DigestUtils.md5DigestAsHex(data.getBytes());
+
+        // check if exists, ignore if exists
+        var notification = UfActiveRecord.findOne(UfMdbNotification.class, Map.of(
+            "hash", hash, "status", "new"
+        ));
+        if ( null != notification ) {
+            return ;
+        }
+
+        notification = new UfMdbNotification();
+        notification.type = type;
+        notification.data = data;
         notification.status = "new";
+        notification.hash = hash;
+
+        var dateFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
+        notification.time = dateFormatter.format(System.currentTimeMillis());
         notification.save();
     }
 
+    // notify error
+    public static void error( String message, Object ... args ) {
+        createNotification("error", String.format(message, args));
+    }
+
     // notify action
     public static void action( String action, Map<String,Object> params) {
         var data = Map.of("action", action, "params", params);
         var dataJson = UfJsonHelper.objectToJson(data);
-        var notification = new UfMdbNotification();
-        notification.type = "action";
-        notification.data = dataJson;
-        notification.status = "new";
-        notification.save();
+        createNotification("action", dataJson);
     }
 }