Chapter 5 - Secondary Indexes
“People can have the Model T in any color – so long as it’s black.”
- Henry Ford
Creating a Unique Secondary Index (USI)
A Subtable is created on each AMP anytime a secondary index is created
We created a Unique Secondary Index (USI) on the column Emp_No named idxname. Remember, that a secondary index requires a separate physical structure (the subtable ), but a Primary Index , Partitioned Primary Index , Multi-Level Partitioned Primary index do NOT require a separate physical structure.
What is in a Unique Secondary Index (USI) Subtable?
The USI Subtable contains two columns:
1. Emp_No (The USI column)
2. Row-ID ...