0 - 2 of 2 tags for PK

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, In our EDW a table is defined with PI on a coumn and Primary key on two other columns . We are running into maintenance issues due to the PI and Primary key. Can someone sugest if this is a good modeling practice ? if yes is thre an alternate approach instead Primary key.  USI is not an option since USI also causig overhead.