Stumbled across a type of index optimization which can be used with Oracle database tables. A Reverse Index, also known as a reverse key index stores the index entries as their bytes reversed, except rowids.
by Yasin BaskanIn single instance databases there is also a case where reverse key indexes can be helpful. If you have a column populated by an increasing sequence, you delete some old rows from the table and you do not do range scans on that column and you have contention issues on index blocks, reverse key indexes can be considered. The reverse key index will scatter the entries accross different blocks during inserting and your many concurrent sessions will not have index block contention issues.
This method offers a new way of managing data entry and output from a situation of large data sets or multiple read/write database sessions involved.