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Message Posted: Fri, 31 Jan 2014 @ 13:23:31 GMT

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Hi Roopalini - the only way to influence the Optimizer for a given query is with statistics and indices.

So, there is no guarantee that the Optimizer will use the indices in the Explain Plan.

Also, keep in mind, Teradata is built to do table scans. If the number of rows is large enough, the Optimizer will not use an index to get the data. It often proves 'cheaper' to read all the data.

It seems that once Teradata has to read 1% of the rows in a table, it usually does a table scan.

I'd like to hear what others think about this 1% rule vis-a-vis table scans.

Good Luck.

Rgrds,

Bill Gregg

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