7.3.3 Query performance problem

This query runs quickly and the explain plan show that it is using an index only range scan on the VarcharColumnB. There are about 600 records with 'E' as a value for VarcharColumnB in a table with a over 100K records.

SELECT count(IntegerColumnA)
FROM Table1
WHERE VarcharColumnB = 'E';

This query runs slowly and does a full table access on the table. Why?

SELECT IntegerColumnA
FROM Table1
WHERE VarcharColumnB = 'E';

Thanks in advance.

--
Ken Walters
kwalters_at_pbs.org
DBA
Public Braodcasting Service
kwalters_at_pbs.org Received on Wed Sep 16 1998 - 10:05:42 CDT