diff --git a/CHANGELOG b/CHANGELOG
index 5137c87a5f34886113f0b05aaa798a851bde1308..a5671948a6fea6d824f2b59a39e0f974fae8e1fa 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 v 6.9.0
   - Store Rails cache data in the Redis `cache:gitlab` namespace
   - Adjust MySQL limits for existing installations
+  - Add db index on project_id+iid column. This prevents duplicate on iid.
 
 v 6.8.0
   - Ability to at mention users that are participating in issue and merge req. discussion