Databases Reference
In-Depth Information
Solution
Use information in V$RMAN_BACKUP_JOB_DETAILS for statistics on backups. The following query displays useful
information regarding the length of time a backup has run and the size of recent backups:
SET PAGESIZE 50
COL time_taken_display FORM A10 HEAD "Time|Taken|HH:MM:SS"
COL rman_end_time FORM A17
COL i_size_gig FORM 999.99 HEAD "Input|Gig"
COL o_size_gig FORM 999.99 HEAD "Output|Gig"
COL compression_ratio FORM 99.99 HEAD "Comp.|Ratio"
COL status FORM A12
COL input_type FORM A14
--
SELECT
time_taken_display
,TO_CHAR(end_time,'dd-mon-rrrr hh24:mi') AS rman_end_time
,input_bytes/1024/1024/1024 i_size_gig
,output_bytes/1024/1024/1024 o_size_gig
,compression_ratio
,status
,input_type
FROM v$rman_backup_job_details
ORDER BY end_time;
Here is a snippet of the output:
Time
Taken Input Output Comp.
HH:MM:SS RMAN_END_TIME Gig Gig Ratio STATUS INPUT_TYPE
---------- ----------------- ------- ------- ------ ------------ --------------
03:06:51 09-aug-2012 18:52 130.12 25.58 5.09 COMPLETED DB INCR
03:05:27 10-aug-2012 18:50 130.06 25.48 5.10 COMPLETED DB INCR
03:06:31 11-aug-2012 18:52 129.90 25.43 5.11 COMPLETED DB INCR
00:00:43 12-aug-2012 09:48 .05 .05 1.00 COMPLETED CONTROLFILE
This output gives you a good indication of RMAN performance. It shows how long the backups are running, when
they finish, input size (in gigabytes) of blocks read, output size of the backup, and so on.
Ti
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Keep in mind that V$rMan_BaCKup_JOB_DetaiLS has many other useful columns that you may want to report
on such as Start_tiMe, input_BYteS_per_SeC_DiSpLaY and Output_BYteS_per_SeC_DiSpLaY. if you are trouble-
shooting i/O issues, you may especially want to report on those columns.
How It Works
Measuring the duration of your backups provides a starting point from which you can begin tuning your RMAN
backups. The V$RMAN_BACKUP_JOB_DETAILS view contains a plethora of information about backup durations and
I/O rates.
