RE: Checkpoint duration - oracle 10g
Date: Mon, 20 Apr 2009 16:40:20 -0500
Message-ID: <FFBBEADAA554654896F09964A4DB90A101BA09B5_at_gemini.cap.org>
Thanks Yong. in the alert log it logs SCN # for the checkpoint, is there a way to get the total # of buffer blocks that were written for the SCN ?
-----Original Message-----
From: Yong Huang [mailto:yong321_at_yahoo.com]
Sent: Monday, April 20, 2009 3:54 PM
To: Savio Pinto (s)
Cc: oracle-l_at_freelists.org
Subject: Re: Checkpoint duration - oracle 10g
> I need to find out how long it takes for the database to flush the
dirty
> buffers to the disk, is there a way I can find the total number of
> buffers that are written to the disk during the checkpoint operation,
> and how long does it take for the database to write it to the disk
> (checkpoint duration) ?
There're a couple of statistics about checkpoint buffers written so you can check v$sysstat to get that number. I don't think there's a way to find how long a checkpoint takes unless you watch your clock while you do checkpoint. But there're many types of checkpoint. For log switch checkpoint, you may get two timestamps in alert.log if you alter system set log_checkpoints_to_alert = true and watch the lines "Beginning log switch checkpoint up to RBA" and "Completed checkpoint up to RBA". Even that is not guaranteed; you may still get only one timestamp so you don't know the duration.
Yong Huang
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