Guidance relating to secondary index and unique column constraint
When we create a table and specify a unique constraint on a specific column(s), and we are not specifying any secondary indexes, but the table is created with secondary indexes with all the columns specified as unique.
This is actually a disk overhead as per my view. we might have a column as unique but doesn't have that column as a access path or to be straight we need not have it as a secondary index.
And also if we drop the secondary index the constraint unique is also dropped and viceversa.
Why secondary index is automatically getting created when we specify a column as unique.