diff --git a/app/operations.py b/app/operations.py
index 77548a7..1c33f66 100644
--- a/app/operations.py
+++ b/app/operations.py
@@ -79,7 +79,7 @@ async def fetch_cursor(
     if cached_cursor.done:
         mysql.cached_cursors.pop(cursor_id, None)
     else:
-        cached_cursor.upgrade_close_at()
+        cached_cursor.close_at = cached_cursor.upgrade_close_at()
 
     return SelectResult(
         cursor=cached_cursor,