diff --git a/gameserver/models/submission.py b/gameserver/models/submission.py
index 01081e1..9e36531 100644
--- a/gameserver/models/submission.py
+++ b/gameserver/models/submission.py
@@ -64,6 +64,5 @@ class Meta:
         indexes = [
             models.Index(fields=['user']),
             models.Index(fields=['problem']),
-            models.Index(fields=['is_correct']),
-            models.Index(fields=['problem__is_public']),
+            models.Index(fields=['is_correct'])
         ]