diff --git a/src/calibre/library/caches.py b/src/calibre/library/caches.py
index 63920c5dc9..f27e15a74b 100644
--- a/src/calibre/library/caches.py
+++ b/src/calibre/library/caches.py
@@ -798,8 +798,8 @@ class ResultCache(SearchQueryParser): # {{{
 
         # Set the values in the cache
         marked_col = self.FIELD_MAP['marked']
-        for id_ in self.iterallids():
-            self._data[id_][marked_col] = None
+        for r in self.iterall():
+            r[marked_col] = None
 
         for id_, val in self.marked_ids_dict.iteritems():
             try: