Skew Ness

Database
Enthusiast

Skew Ness

Hi,

I know if we are not creating and loading table with out proper primary index, will be getting skew ness in AMPS. But i head that even if we create a table with proper primary index, but if it has less number of records (less than no of AMPS available), then also it will create the Skew ness. As per my idea it will not create.

Please let me know

Thanks!

Regards

Rajesh A

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2 REPLIES
Teradata Employee

Re: Skew Ness

Most of the tools and published queries calculate a "relative" skew value rather than some sort of absolute measure.

If most AMPs have only table headers but a few AMPs also have a data row, the calculation will show a high relative skew. But in absolute terms, the difference is trivial (and expected).

Rather than trying to adjust the definition of "skew", I generally suggest people ignore skew until the total amount of data exceeds a few MB per AMP.

Enthusiast

Re: Skew Ness

Thank you Fred