How to tune up this simple query

I have this table named testresult with 10 million records: id number(10) --pk, indexed
testid number(10) --fk reference to test.id, indexed result varchar2(100)

The following query takes 20 seconds:
select min(id) from testresult where testid > 100000;

I have a program that does this query in a loop(because testid keep changing). So 20 seconds is not acceptable.

How to tune this up? How come it doesn't use index of testid? The explain plan shows it's doing a full table scan instead of using index of testid.

Thanks,
ewong Received on Mon Jan 28 2002 - 15:29:45 CST