RE: ???.: ???.: How to track logfile switch

From: Baumgartel, Paul <paul.baumgartel_at_credit-suisse.com>
Date: Fri, 3 Oct 2008 12:37:31 -0400
Message-ID: <21469B88E0EA11498818517F210335310455B63A@EPRI17P32001A.csfb.cs-group.com>


DML causes redo to be written. When a redo log becomes full, a log switch takes place.  

Paul Baumgartel
CREDIT SUISSE
Information Technology
Prime Services Databases Americas
One Madison Avenue
New York, NY 10010
USA
Phone 212.538.1143
paul.baumgartel_at_credit-suisse.com
www.credit-suisse.com  


From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Yavor Ivanov Sent: Friday, October 03, 2008 12:00 PM
To: Bort, Guillermo; Bobak, Mark; oracle-l Subject: ???.: ???.: How to track logfile switch

This sound promising. What DML could cause log switch (other than "alter system switch logfile" and "alter system archive log ...")?  

The issue happens during normal daily load.  

Regards,

Yavor Ivanov


: Bort, Guillermo [guillermo.bort_at_eds.com] : 03 2008 . 18:45
: Yavor Ivanov; Bobak, Mark; oracle-l
: RE: .: How to track logfile switch

It may be silly to mention this, however log switches can be caused by valid dml processing not just alter system switch logfile. I've found that increasing redo log size and redo log buffer often helps lower the number of Checkpoint not Complete. Do you notice this issue during periods of high transaction load or batch load? Also, do you have fast_start_mttr_target set to a static value?  

HTH   Guillermo Alan Bort

EDS - ITO DBA Main Group  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Yavor Ivanov Sent: Friday, October 03, 2008 12:36 PM
To: Bobak, Mark; oracle-l
Subject: .: How to track logfile switch  

 The value of ARCHIVE_LAG_TARGET is 0  

Unfortunately the message "Thread X cannot allocate new log, sequence XXXX" is sometimes followed by "Checkpoint not complete". So I cannot ignore it easily. Yesterday there was a short but noticeable database hang at the same time when this happened.  

Regards,

Yavor Ivanov

[SNIP]



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Received on Fri Oct 03 2008 - 11:37:31 CDT

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