How long does the rollback segment hold data to maintain consistency? | Oracle DBA

Rollback segment holds the previous version of data block until either it gets committed or the space is not available for reuse. If a session is reading specific block from rollback segment while the other session has committed the information, then more rollback space is required to maintain more rollback information. In that case, this specific block ages out of the rollback segment and the reading or selecting session gets an error.