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Oracle® Database Reference
10g Release 1 (10.1)

Part Number B10755-01
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DBA_HIST_ROLLSTAT

DBA_HIST_ROLLSTAT displays historical rollback segment statistics. This view contains snapshots of V$ROLLSTAT.

Column Datatype NULL Description
SNAP_ID NUMBER NOT NULL Unique snapshot ID
DBID NUMBER NOT NULL Database ID for the snapshot
INSTANCE_NUMBER NUMBER NOT NULL Instance number for the snapshot
USN NUMBER NOT NULL Rollback segment number
EXTENTS NUMBER   Number of extents in the rollback segment
RSSIZE NUMBER   Size (in bytes) of the rollback segment. This value differs from the value of the BYTES column of the DBA_SEGMENTS views by the number of bytes in one database block.
WRITES NUMBER   Number of bytes written to the rollback segment
XACTS NUMBER   Number of active transactions
GETS NUMBER   Number of header gets
WAITS NUMBER   Number of header waits
OPTSIZE NUMBER   Optimal size of the rollback segment
HWMSIZE NUMBER   High-watermark of the rollback segment size
SHRINKS NUMBER   Number of times the size of a rollback segment decreased
WRAPS NUMBER   Number of times the rollback segment has wrapped
EXTENDS NUMBER   Number of times the rollback segment size has extended
AVESHRINK NUMBER   Average shrink size
AVEACTIVE NUMBER   Current size of active extents, averaged over time