Purpose
Use the DROP ROLLBACK SEGMENT to remove a rollback segment from the database. When you drop a rollback segment, all space allocated to the rollback segment returns to the tablespace.
Note:
If your database is running in automatic undo mode, then this is the only valid operation on rollback segments. In that mode, you cannot create or alter a rollback segment.Prerequisites
You must have the DROP ROLLBACK SEGMENT system privilege, and the rollback segment must be offline.
Syntax
drop_rollback_segment::=
Description of drop_rollback_segment.gif followsSemantics
rollback_segment
Specify the name the rollback segment to be dropped.
Restrictions on Dropping Rollback Segments This statement is subject to the following restrictions:
You can drop a rollback segment only if it is offline. To determine whether a rollback segment is offline, query the data dictionary view DBA_ROLLBACK_SEGS. Offline rollback segments have the value AVAILABLE in the STATUS column. You can take a rollback segment offline with the OFFLINE clause of the ALTER ROLLBACK SEGMENT statement.
You cannot drop the SYSTEM rollback segment.
Examples
Dropping a Rollback Segment: Example The following syntax drops the rollback segment created in "Creating a Rollback Segment: Example":
DROP ROLLBACK SEGMENT rbs_one;
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