1. Database Reference
  2. Dynamic Performance Views
  3. Dynamic Performance (V$) Views: V$ACCESS to V$HVMASTER_INFO
  4. V$BACKUP_ASYNC_IO

7.86 V$BACKUP_ASYNC_IO

V$BACKUP_ASYNC_IO displays performance information about ongoing and recently completed RMAN backups and restores.

For each backup, it contains one row for each input data file, one row for the aggregate total performance of all data files, and one row for the output backup piece. This data is not stored persistently, and is not preserved when the instance is re-started.

Column Datatype Description

SID

NUMBER

Oracle SID of the session doing the backup or restore

SERIAL

NUMBER

Use count for the SID doing the backup or restore

USE_COUNT

NUMBER

A counter that can be used to identify rows from different backup sets

RMAN_STATUS_RECID

NUMBER

Owning V$RMAN_STATUS record ID

RMAN_STATUS_STAMP

NUMBER

Owning V$RMAN_STATUS record stamp

DEVICE_TYPE

VARCHAR2(17)

Device type where the file is located

TYPE

VARCHAR2(9)

INPUT, OUTPUT, or AGGREGATE

STATUS

VARCHAR2(11)

NOT STARTED, IN PROGRESS, or FINISHED

FILENAME

VARCHAR2(513)

Name of the backup file being read or written

SET_COUNT

NUMBER

Set count of the backup set being read or written

SET_STAMP

NUMBER

Set stamp of the backup set being read or written

BUFFER_SIZE

NUMBER

Size of the buffers being used to read/write the file, in bytes

BUFFER_COUNT

NUMBER

Number of buffers being used to read/write the file

TOTAL_BYTES

NUMBER

Total number of bytes that will be read or written for the file, if known. If not known, this column will be null

OPEN_TIME

DATE

Time the file was opened. If TYPE='AGGREGATE', then this is the time that the first file in the aggregate was opened

CLOSE_TIME

DATE

Time the file was closed. If TYPE='AGGREGATE', then this is the time that the last file in the aggregate was closed

ELAPSED_TIME

NUMBER

Time, in hundredths of a second, that the file was open

MAXOPENFILES

NUMBER

Number of concurrently open DISK files. This value is only present in rows where TYPE='AGGREGATE'.

BYTES

NUMBER

Number of bytes read or written so far

EFFECTIVE_BYTES_PER_SECOND

NUMBER

I/O rate that was achieved with this device during this backup

IO_COUNT

NUMBER

Number of I/Os that were performed to this file

READY

NUMBER

Number of asynchronous requests for which a buffer was immediately ready for use

SHORT_WAITS

NUMBER

Number of times that a buffer was not immediately available, but a buffer became available after doing a nonblocking poll for I/O completion

SHORT_WAIT_TIME_TOTAL

NUMBER

Total time, in hundredths of a second, taken by nonblocking polls for I/O completion

SHORT_WAIT_TIME_MAX

NUMBER

Maximum time taken for a nonblocking poll for I/O completion, in hundredths of a second

LONG_WAITS

NUMBER

The number of times that a buffer was not immediately available, and only became available after a blocking wait was issued

LONG_WAIT_TIME_TOTAL

NUMBER

The total time, in hundredths of a second, taken by blocking waits for I/O completion

LONG_WAIT_TIME_MAX

NUMBER

The maximum time taken for a blocking wait for I/O completion, in hundredths of a second

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