I want to add an index on the system$changedate attribute, but in the modeler that attribute isn't selectable :(. So I add it manually on the database, but each time of starting the application it deletes my indexes. Is there a way to do this so that the XAS will accept my indexes? Without this index certain retrieves will never perform because the big amount of records..
No there is no way to bypass the check for a consistent database structure. If you want indices on the read-only system entities, make a ticket for it, maybe it can be made configurable in some way.