diff --git a/group/handlers.py b/group/handlers.py
index 3cb1d7320e..92ad999c4a 100644
--- a/group/handlers.py
+++ b/group/handlers.py
@@ -6,8 +6,7 @@ from seahub.notifications.models import UserNotification
 def grpmsg_added_cb(sender, **kwargs):
     group_id = kwargs['group_id']
     from_email = kwargs['from_email']
-    l = UserNotification.objects.filter(msg_type='group_msg',
-                                        detail=group_id)
+    l = UserNotification.objects.filter(msg_type='group_msg', detail=group_id)
     if len(l) == 0:
         group_members = ccnet_threaded_rpc.get_group_members(int(group_id))
         for m in group_members:
diff --git a/notifications/models.py b/notifications/models.py
index c5d46387ef..7ec9c35e5c 100644
--- a/notifications/models.py
+++ b/notifications/models.py
@@ -6,8 +6,8 @@ class Notification(models.Model):
     primary = models.BooleanField(default=False)
 
 class UserNotification(models.Model):
-    to_user = models.EmailField(max_length=255)
-    msg_type = models.CharField(max_length=30)
+    to_user = models.EmailField(db_index=True, max_length=255)
+    msg_type = models.CharField(db_index=True, max_length=30)
     detail = models.TextField()
     
 class NotificationForm(ModelForm):