Saturday 22 February 2014

HASHFunctions in TERADATA

What are the types of HASH functions used in teradata?

These are the types of HASH, HASHROW, HASHAMP and HASHBAKAMP. Their SQL functions are-
HASHROW (column(s))
HASHBUCKET (hashrow)
HASHAMP (hashbucket)
HASHBAKAMP (hashbucket)

To find the data distribution of a table based on PI, below query will be helpful. This query will give the number of records in each AMP for that particular table.


SELECT HASHAMP(HASHBUCKET(HASHROW(PI_COLUMN))),COUNT(*) FROM TABLENBAME GROUP BY 1.

No comments:

Post a Comment