Ignore (or at least treat very lightly) the comments about DBWm.
Excessive database writes can cause log file sync waits, as
dbwr calls lgwr to write the log protecting the blocks it is
about to write. In this case, you will see v$session_event
for the db writers showing log file waits. Unfortunately I
have a mental block that makes me explain this phenomenon
100% the wrong way round every 6 months or so. And that
is what I did last night.
I suspect you are also going to tell me that the anomalous
difference between CPU and elapsed time on the one big
update is because everything else is done by triggers,
and the update is waiting for triggers to complete ;(
4GB of redo log in 50 minutes is quite a lot.
Unless I've done the arithmetic wrong, that's
close to 1.4MB per second (or 2.8 since you are
using Oracle duplexing). It seems a little odd that
you are getting 'log file sync' as a problem
without getting (in your case) 'log buffer space'
and 'log file ... write'.
What is your average log file write size ?
(redo blocks written / redo writes). and
what do you other 'redo%' stats look like
over the period ?
How many CPUs ?
Jonathan Lewis
Seminars on getting the best out of Oracle
Last few places available for Sept 10th/11th
See http://www.jlcomp.demon.co.uk/seminar.html
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Jonathan Lewis
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
