Re: "latch: cache buffers chains" wait in NON-RAC Benchmark Runs
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: "VIVEK_SHARMA" <VIVEK_SHARMA@xxxxxxxxxxx>
- Date: Sat, 16 Feb 2008 10:18:34 -0000
My comment on the Metalink note was:
The biggest problem with the Metalink article is that it supplies a
ridiculous
query to report the "problem object" from the child latch address.
If you read the Metalink note you would see that they first
tell you how to find the child latch address before telling
you a bad way of using it.
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: "VIVEK_SHARMA" <VIVEK_SHARMA@xxxxxxxxxxx>
To: <jonathan@xxxxxxxxxxxxxxxxxx>
Cc: <oracle-l@xxxxxxxxxxxxx>
Sent: Saturday, February 16, 2008 4:47 AM
Subject: RE: "latch: cache buffers chains" wait in NON-RAC Benchmark Runs
Thanks Jonathan for responding & the clarifications
U wrote -> "select obj, tch from sys.x$bh where hladdr =
'6F9CBE00' -- adjust as necessary"
How is the Value of "hladdr" to be specified for our NON-RAC database?
Oracle 10gR2
Cheers
Vivek
________________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
Jonathan Lewis [jonathan@xxxxxxxxxxxxxxxxxx]
Sent: Friday, February 15, 2008 9:39 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: "latch: cache buffers chains" wait in NON-RAC Benchmark Runs
The biggest problem with the Metalink article is that it supplies a ridiculous
query to report the "problem object" from the child latch address. Do NOT run
that
query on a real production system.
You have to temper the touch count with knowledge aboutwhat MIGHT have been
happening to the objects.To help you address the problem, you may get more
cluesfrom a simple statspack/awr report - find the SQL that doesmost gets, and
check the segment statistics for the objectssubject to most buffer gets - cross
reference to see if thetwo sets of information are consistent, then see if
youcan reduce the work done by those statements.
Regards
Jonathan Lewis
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