When i tried finding the Row hash value for the unique column which have all unique values ,i saw that all row hash value matches for every single record present there.
http://www.teradatatech.com/?p=470 this link suggest that row hash values cannot be same for unique as well as non unique columns.
please clarify me on this question.
The Teradata hash function is deterministic - same input values always give the same result. It's possible (but unusual) for different input values to give the same result, referred to as a "hash collision".