RE: LGWR blocking sessions
- From: "MacGregor, Ian A." <ian@xxxxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 11 Jun 2009 15:51:51 -0700
OEM should provide more information, are they log buffer waits, log file synch,
etc. Where are the online redologs located? Are these waits actually causing
any problems? How long does the blocking last? How many sessions are queued?
Ian MacGregor
SLAC National Accelerator Center
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Joel.Patterson@xxxxxxxxxxx
Sent: Thursday, June 11, 2009 12:41 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: LGWR blocking sessions
My log writer is triggering an alert from OEM that it is blocking
sessions. (SID ### is blocking -- which is LGWR).
I have googled, and searched metalink, and come across log file sync's,
and even Kevin Closson's interesting blog about io and cpu (again :)).
Even though I can find people (several) with the same issue and
question, I did not come up with any solutions that where directed
specifically.
10.2.0.4, peoplesoft, SAN. Sidenote. Archiver is copying logfiles to a
Quantum dxi7500, (with compression and deduping software bundled).
Any ideas where to go from here? (I'll be back early tomorrow)
Alert log snippet during time receiving two such alerts which looks
normal. No trace files. Some db's have been know to warn of the 500ms
write threshold was exceeded, but not here now.
Thu Jun 11 11:04:57 2009
Beginning log switch checkpoint up to RBA [0x1bc1.2.10], SCN: 2847388841
Thu Jun 11 11:04:57 2009
Thread 1 advanced to log sequence 7105 (LGWR switch)
Current log# 1 seq# 7105 mem# 0: /u02/oradata/HRPROD/log01a.log
Current log# 1 seq# 7105 mem# 1: /u03/oradata/HRPROD/log01b.log
Thu Jun 11 11:10:02 2009
Completed checkpoint up to RBA [0x1bc1.2.10], SCN: 2847388841
Thu Jun 11 12:11:53 2009
Beginning log switch checkpoint up to RBA [0x1bc2.2.10], SCN: 2847490018
Thu Jun 11 12:11:53 2009
Thread 1 advanced to log sequence 7106 (LGWR switch)
Current log# 2 seq# 7106 mem# 0: /u02/oradata/HRPROD/log02a.log
Current log# 2 seq# 7106 mem# 1: /u03/oradata/HRPROD/l0g02b.log
Thu Jun 11 12:17:11 2009
Completed checkpoint up to RBA [0x1bc2.2.10], SCN: 2847490018
Thu Jun 11 13:07:20 2009
Beginning log switch checkpoint up to RBA [0x1bc3.2.10], SCN: 2847597436
Thu Jun 11 13:07:20 2009
Thread 1 advanced to log sequence 7107 (LGWR switch)
Current log# 3 seq# 7107 mem# 0: /u02/oradata/HRPROD/log03a.log
Current log# 3 seq# 7107 mem# 1: /u03/oradata/HRPROD/log03b.log
Thu Jun 11 13:12:36 2009
Completed checkpoint up to RBA [0x1bc3.2.10], SCN: 2847597436
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