RE: 10g Automatic Checkpoint Tuning
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
- To: <yoursraju007@xxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 25 Jun 2007 17:56:14 -0400
Just a guess....
Are you using buffered filesystems and RAID-5 storage? Stop doing
that....especially for the on-line redo log!
-Mark
Mark J. Bobak
Senior Oracle Database Administrator, System & Product Technologies
ProQuest
789 E. Eisenhower, Parkway, P.O. Box 1346
Ann Arbor MI 48106-1346
734.997.4059 or 800.521.0600 x 4059
mark.bobak@xxxxxxxxxxxxxxx
www.proquest.com
www.csa.com
ProQuest...Start here.
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Raj Mareddi
Sent: Monday, June 25, 2007 5:10 PM
To: oracle-l
Subject: 10g Automatic Checkpoint Tuning
Guys,
The following are the top-4 waits after CPU Time in my AWR reports
during a batch window.
log file switch (checkpoint incomplete)
free buffer waits
log file switch (private strand flush incomplete) log file parallel
write
Just realized that log switches are happening very frequent.. each log
member is 300M and 3 groups. this size seems to be okay.. other database
has 100M member and the same batch job runs good there.
First wait says, checkpoint incomplete.. I have started looking at
checkpoint tuning.. I have uncommented the following parameters
- LOG_CHECKPOINT_INTERVAL
- LOG_CHECKPOINT_TIMEOUT
and set FAST_START_MTTR_TARGET to 60... Still dint see any big
difference. Has anyone started using FAST_START_MTTR_TARGET for
automatic checkpoint tuning ? Document says if we just need checkpoint
tuning, we need to set this higher.. but it doesn't say how higher..
Im thinking of going back to old boat of setting using interval value or
FAST_START_MTTR_TARGET to a very high no#. . Any comments please.
Automatic Checkpoint Tuning in 10g: 265831.1
REDO LOGS SIZING ADVISORY: 274264.1
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