On Postgres, a unique index is automatically created for primary key columns. From the docs,
When an index is declared unique, multiple table rows with equal indexed values are not allowed. Null values are not considered equal. A multicolumn unique index will only reject cases where all indexed columns are equal in multiple rows.
From my understanding, it seems like this index only checks uniqueness and isn't actually present for faster access when querying by primary key id's. Does this mean that this index structure doesn't consist of a sorted table (or a tree) for the primary key column? Is this correct?
