RE: Rapid Log Switching

This has been going on for about 19 hours now, and the system isn't
being hammered.  If it was, I could understand the log switches.  But I
have 20M logs that are switching when 2-6M in size.  I did have problems
with AWR before, but that is now under control....and then this
starts.....

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jonathan Lewis
Sent: Wednesday, February 20, 2008 2:52 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: Rapid Log Switching


What time did it start ?

Are you aware of the automatic stats collection that takes
place in 10g ?  This runs to collects stats on objects with stale
statistics every night with a window that is something like
midnight to 6 am.

Your system might run for weeks doing a couple of minutes
of stats collection every (weekday) night, and then decide one
night that most of the tables in the system have gone stale and
hammers the system for hours on end.


Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html


----- Original Message ----- 
From: "Weatherman, John" <John.Weatherman@xxxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Cc: "Terrell, Paul" <Paul.Terrell@xxxxxxxxxxx>; "Shamim, Aziz" 
<Aziz.Shamim@xxxxxxxxxxx>
Sent: Wednesday, February 20, 2008 7:58 PM
Subject: Rapid Log Switching


All,



I'm on RH 2.6.9-42.ELsmp x86_64 Linux, running 10.2.0.3.  I've been
having a lot of log issues for the last week.  Thanks to some help here,
I seem to have the worst of it under control now.



However, last night I began seeing log switches every 6 minutes.  The
logs are 20M in size, but are switching between 2-6M.  We do have
log_checkpoint_timeout set, but it is 1800 seconds (30 minutes), not 6
minutes.



Does anyone have any ideas what other than the timeout or the log
filling up would cause a log switch?  It's not manual and it's not
backups, it's been too consistent and too long for either of those to
make any sense.  I'm not aware of anything else that should be
triggering log switches and haven't been able to find anything
suspicious with Google or Metalink.



TIA,



John



John P Weatherman    john.weatherman@xxxxxxxxxxx

Sr Oracle DBA            Desk:   (615) 762-1376

Asurion, Inc                Mobile: (615) 517-2831



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