diff --git a/artiq/master/worker_db.py b/artiq/master/worker_db.py
index 1a4ef61e67..22190a087f 100644
--- a/artiq/master/worker_db.py
+++ b/artiq/master/worker_db.py
@@ -227,9 +227,9 @@ def get(self, key, archive=False):
         else:
             data = self.ddb.get(key)
             if archive:
-                if key in self.archive:
-                    logger.warning("Dataset '%s' is already in archive, "
-                                   "overwriting", key, stack_info=True)
+                if self.archive.get(key, data) != data:
+                    logger.warning("Older value of dataset '%s' is already in "
+                                   "archive, overwriting", key, stack_info=True)
                 self.archive[key] = data
             return data