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Undo Header Dump

To dump an undo segment header use the command function

    ALTER SYSTEM DUMP UNDO_HEADER 'segment_name';

In Oracle 9.0.1 and above, if system managed undo is enabled, the segment name has to be in double quotes and upper case. This is because there is a leading underscore in the segment name.

A list of undo segment IDs and names can be obtained using

    SELECT segment_id, segment_name
    FROM dba_rollback_segs
    ORDER BY segment_id;