USN

NUMBER

Rollback segment number

LATCH

NUMBER

Latch for the rollback segment

EXTENTS

NUMBER

Number of extents in the rollback segment

RSSIZE

NUMBER

Size (in bytes) of the rollback segment. This value differs by the number of bytes in one database block from the value of the BYTES column of the *_SEGMENTS view.

See Also: Oracle Database Administrator’s Guide for more information about space management for rollback segments

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 decreases

WRAPS

NUMBER

Number of times rollback segment is wrapped

EXTENDS

NUMBER

Number of times rollback segment size is extended

AVESHRINK

NUMBER

Average shrink size

AVEACTIVE

NUMBER

Current size of active extents, averaged over time.

STATUS

VARCHAR2(15)

Rollback segment status:

• ONLINE

• PENDING OFFLINE

• OFFLINE

• FULL

CUREXT

NUMBER

Current extent

CURBLK

NUMBER

Current block

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

• 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

• 1: This value is used for rows containing data that pertain to only the root

• n: Where n is the applicable container ID for the rows containing data