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Teradata SQL by Tom Coffing, Mike Larkins

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Chapter 29 - Hashing Functions

“Love, like a chicken salad or restaurant hash, must be taken with blind faith or it loses its flavor. “

-Helen Rowland

 

Hashing Functions on Teradata

Teradata uses Parallel Processing, and the most important aspect of this is to spread the rows of a table equally among the AMPs who read and write data.

Below, are the four Hashing Functions available to see the distribution of data:

HASHROW HASHAMP
HASHBUCKET HASHBAKAMP

Teradata uses parallel processing with its architecture of AMPs and PEs. The Primary Index (PI) must exist whenever you create a table because it is the sole determinant of which AMPs owns which rows. This concept pertains to data storage and data retrieval. Picking the proper column(s) ...

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