ORA-01636

Error: ORA-01636: rollback segment 'string' is already online

Causa: A rollback segment can only be used by one instance and an instance is trying to bring a rollback segment online that is already in use.

Acción: Check that the values set in the initialization parameter file for parameters ROLLBACK_SEGMENTS, ROLLBACK_SEGMENT_INITIAL, and ROLLBACK_SEGMENT_COUNT are correctly set for the instance with the problem. Also check that the instance is using the correct initialization parameter file. Make sure you are not confused about the difference between private and public rollback segments. See the Oracle9i Database Administrator's Guide for more information about using rollback segments in parallel mode.