The current size of our database is approximately 35GB. The version of DB is Oracle 8.1.7.

The Rollback segments is currently holding approximately 1.25GB data and INDEX segment is currently holding 2.73 GB data.

How to shrink or tune these segments? How can I know whether this much space is really required to occupy lookig at the application and database perspective?

How to dig a deep to shrink or tune these segments?

Thanks in advance.