RE: ???.: ???.: How to track logfile switch
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
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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
ïÔ: Bort, Guillermo [guillermo.bort_at_eds.com]
éÚÐÒÁÔÅÎÉ: 03 ïËÔÏÍ×ÒÉ 2008 Ç. 18:45
äÏ: Yavor Ivanov; Bobak, Mark; oracle-l
ôÅÍÁ: RE: ïôî.: 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: ïôî.: 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
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