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Doubt on Online Backup [message #563112] Wed, 08 August 2012 15:21 Go to next message
neelthom
Messages: 2
Registered: August 2012
Location: India
Junior Member

Hi Friends,

I am a starter and got a basic doubt,I read somewhere that online backup slows down the application for that period,is that true??
If so,then anybody please explain why it so..

Any help on this will be appreciated.


Thanks
Re: Doubt on Online Backup [message #563118 is a reply to message #563112] Wed, 08 August 2012 15:58 Go to previous messageGo to next message
alan.kendall@nfl.com
Messages: 163
Registered: June 2012
Location: Culver City, California
Senior Member
Neel,

The RMAN backup will use cpu and I/O. Here are two queries that will tell you what is taking up all the time within Oracle. The first tells you percentages of all waits of both fore ground and back ground. The second tells you only of fore ground (end user waits).

Thanks to John Watson we just put together the second (fore ground) query.
ENDOCP1P > @v$sys_time_model_top_Waits.sql

WAIT_CLASS           NAME                                     TIME_SECS    PCT
-------------------- ------------------------------ ------------------- ------
Other                log switch/archive                           50.35    .72
Other                enq: WF - contention                         52.31    .74
System I/O           log file parallel write                      68.07    .97
User I/O             db file scattered read                       78.82   1.12
User I/O             direct path read                             82.38   1.17
Other                reliable message                             92.55   1.32
System I/O           control file sequential read                106.26   1.51
User I/O             db file sequential read                     277.91   3.95
System I/O           RMAN backup & recovery I/O                2,672.65  38.00
CPU                  server CPU                                3,019.11  42.92

ENDOCP1P > list
  1  SELECT
  2     wait_class,
  3     NAME,
  4     ROUND (time_secs, 2) time_secs,
  5     ROUND (time_secs * 100 / SUM (time_secs) OVER (), 2) pct
  6  FROM
  7     (SELECT
  8        n.wait_class,
  9        e.event NAME,
 10        e.time_waited / 100 time_secs
 11      FROM
 12        v$system_event e,
 13        v$event_name n
 14      WHERE
 15         n.NAME = e.event AND n.wait_class <> 'Idle'
 16      AND
 17         time_waited > 0
 18      UNION
 19      SELECT
 20        'CPU',
 21        'server CPU',
 22        SUM (VALUE / 1000000) time_secs
 23      FROM
 24        v$sys_time_model
 25      WHERE
 26        stat_name IN ('background cpu time', 'DB CPU'))
 27  ORDER BY
 28*    time_secs

ENDOCP1P > @v$sys_time_model_top_Waits_fore_ground.sql

WAIT_CLASS           NAME                                     TIME_SECS    PCT
-------------------- ------------------------------ ------------------- ------
User I/O             db file scattered read                       26.23    .75
System I/O           control file sequential read                 31.14    .89
Other                log switch/archive                           50.35   1.44
User I/O             direct path read                             82.38   2.35
User I/O             db file sequential read                      91.68   2.62
CPU                  server CPU                                3,019.97  86.20

ENDOCP1P > list
  1  SELECT
  2     wait_class,
  3     NAME,
  4     ROUND (time_secs, 2) time_secs,
  5     ROUND (time_secs * 100 / SUM (time_secs) OVER (), 2) pct
  6  FROM
  7     (SELECT
  8        n.wait_class,
  9        e.event NAME,
 10        e.time_waited_fg / 100 time_secs
 11      FROM
 12        v$system_event e,
 13        v$event_name n
 14      WHERE
 15         n.NAME = e.event AND n.wait_class <> 'Idle'
 16      AND
 17         time_waited_fg > 0
 18      UNION
 19      SELECT
 20        'CPU',
 21        'server CPU',
 22        SUM (VALUE / 1000000) time_secs
 23      FROM
 24        v$sys_time_model
 25      WHERE
 26        stat_name IN ('background cpu time', 'DB CPU'))
 27  ORDER BY
 28*    time_secs
Re: Doubt on Online Backup [message #563430 is a reply to message #563118] Mon, 13 August 2012 14:55 Go to previous message
neelthom
Messages: 2
Registered: August 2012
Location: India
Junior Member

Thank you very much for your detail explanation Alan..highly appreciable.

Take care.
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