If you have a large table, and perform a SQL Select, Rushmore might USE AGAIN the table with a filter in effect. The BIG problem with this (which I think is a bug), is that the entire file is still available as are the records of original files. Rushmore should always return the same type of cursor regardless of what it had to do. The bug is also in the GO command, which disregards the rushmore filtered file and actually GO's to the record in the parent file, not the query result!

For example:

SELECT * FROM TESTFILE WHERE KEYFIELD = 1 && Keyfield is indexed
* Should return 1 record
GO 1
? KEYFIELD
GO 2
? KEYFIELD && prints record 2 keyfield
GO 3
? KEYFIELD && prints record 3 keyfield

Same Code with NOFILTER:
SELECT * FROM TESTFILE WHERE KEYFIELD = 1 NOFILTER
GO 1
? KEYFIELD
GO 2 && EOF error
GO 3 && EOF error