diff --git a/oml/changelog.py b/oml/changelog.py
index a8efc67..ef7de1d 100644
--- a/oml/changelog.py
+++ b/oml/changelog.py
@@ -67,7 +67,10 @@ class Changelog(db.Model):
         # fixme remove
         c = cls()
         c.created = datetime.utcnow()
-        c.timestamp = datetime2ts(ts)
+        if ts:
+            c.timestamp = datetime2ts(ts)
+        else:
+            c.timestamp = datetime2ts(c.created)
         c.user_id = user.id
         c.revision = cls.query.filter_by(user_id=user.id).count()
         c.data = json.dumps([action] + list(args), ensure_ascii=False)