Oracle® Database 11g / 12c / 18c error codes ORA-01581: attempt to use rollback segment ([string]) new extent ([string]) which is being allocated

ORA-01581: attempt to use rollback segment ([string]) new extent ([string]) which is being allocated

Oracle Error Code: ORA-01581

Cause: Undo generated to extend a rollback segment run out of current undo block space and is attempting to write into the new extent which has not been completely allocated.

Action: The rollback segment extending will be rollbacked by the system, no more extension will be possible untill the next extent is freed up by rolling back or committing other transactions.