RE: log file sync
- From: Timur Akhmadeev <Akhmadeev@xxxxxxxxxxxxxx>
- To: "Amir.Hameed@xxxxxxxxx" <Amir.Hameed@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 7 Aug 2012 09:56:38 +0000
Hi
Refer to this post:
http://kevinclosson.wordpress.com/2007/07/21/manly-men-only-use-solid-state-disk-for-redo-logging-lgwr-io-is-simple-but-not-lgwr-processing/
Regards
Timur Akhmadeev
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Hameed, Amir
Sent: Monday, August 06, 2012 23:56
To: oracle-l@xxxxxxxxxxxxx
Subject: log file sync
Hi all,
My AWR report shows 'log file sync' among the top five events. When I look at
the 'Foreground Wait Events', I see the following:
Avg
%Time Total Wait wait
Waits % DB
Event Waits -outs Time (s) (ms)
/txn time
-------------------------- ------------ ----- ---------- -------
-------- ------
log file sync 166,765 0 3,575 21
1.1 3.3
The 'Background Wait Events' section shows the following for 'log file sync'
and 'log file parallel write':
Avg
%Time Total Wait wait
Waits % DB
Event Waits -outs Time (s) (ms)
/txn time
-------------------------- ------------ ----- ---------- -------
-------- ------
log file sync 56 0 1 11
0.0 .0
log file parallel write 221,159 0 1 0
1.4 .0
My question is that if the LGWR is not waiting for the 'log file parallel
write' during synchronous writes (avg. wait time=0) then why is the average
wait time of 'log file sync' event for the foreground and background processes
(DBWR, LMS etc.) is high?
Thanks
Amir
--
//www.freelists.org/webpage/oracle-l
________________________________
The information transmitted herein is intended only for the person or entity to
which it is addressed and may contain confidential, proprietary and/or
privileged material. Any review, retransmission, dissemination or other use of,
or taking of any action in reliance upon, this information by persons or
entities other than the intended recipient is prohibited. If you received this
in error, please contact the sender and delete the material from any computer.
--
//www.freelists.org/webpage/oracle-l
Other related posts:
