Re: How to tune up this simple query

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On 28 Jan 2002 13:29:45 -0800, ewong_at_mail.com (Ed Wong) wrote:

>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 Thu Jan 31 2002 - 18:02:10 CST