John,
Could it be that the primary key contains a FOR clause (e.g. FOR NOT DELETED())? Filtered indexes are ignored by Rushmore.

>Hi,
> I am having Customer ID as primary key for my customer table. I found that, it is slow for searching a customer record using either LOCATE FOR or SQL-SELECT. Therefore, I set Customer ID as regular key in table as well. It really optimized the query. The speed of search is just like "light of speed".
>
>Why could it happen?
>
>Thank you