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What are the reason(s) why a PK will be implemented as USI instead of UPI? This question was formulated based on the following statement:
"Primary keys are implemented as unique secondary indexes for non-temporal tables..."

Hello All,
 
Can someone explain on what basis we select indexes for the columns in the field.
Following is my understand:
UPI -> When we have Unique value, which is evenly distributed to all the AMPS. (The column selected for UPI looks like a field Eligible for USI as well. Then how to decide?)