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Message Posted: Tue, 19 Oct 2010 @ 16:01:41 GMT

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Hi,

In my experience EVERY Teradata system uses some indexes other than Primary. Typically there are not as many 'alternate' indexes in a Teradata system as you would use in an OLTP system or a non-Teradata data warehouse, but they're still there.

As with any dbms there are trade-off's.

Alternate indexes are added with the intention of speeding up read processing. However they will add space and they may slow down maintenance processing.

As a rough rule of thumb, if I see more than 2 or 3 alternate indexes defined on a table then that raises questions (for me) about the design.

Even if a table doesn't have alternate indexes defined directly on the table, the user of join indexes (aggregate or otherwise) is becoming more common.

Cheers,

Dave

Ward Analytics Ltd - Information in motion ( www.ward-analytics.com )

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