Archives of the TeradataForum

Message Posted: Tue, 08 Dec 2009 @ 16:22:33 GMT

	<Prev	Next>		<<First	<Prev	Next>	Last>>

Continuing on, a secondary index "might" make the query run faster if it can identify specific rows (and corresponding blocks) to pull based on the selectivity of the value; lower is better.

So for a table with a column having 3 values where value a is 80% of rows and values b & c are 10% respectively, the optimizer might use the secondary index to pull rows for values b or c if specified.

As always, you must test to determine the value of stats or indexes.

Dave

David W. Roth
Teradata Certified Master
TERADATA

	<Prev	Next>		<<First	<Prev	Next>	Last>>