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RE: X$ksmsp (OSEE 10.2.0.2 on Solaris 8)

From: Lawie, Duncan <duncan.lawie_at_credit-suisse.com>
Date: Tue, 27 Jun 2006 13:12:07 +0100
Message-ID: <07150B51CE30744CBBB58E696139708DFDD95F@elon11p32002.csfp.co.uk>


Charles,  

I agree that a row in x$ksmsp should equal a single memory chunk - but is it possible that there is a chunk with an outrageous value? I don't recall that particular case, but I have seen x$ksmsp sum to values significantly larger than the size of the SGA.  

In addition, I have also had significant performance issues on a production system when selecting on this table in a very busy system which is severely fragmented.  

Cheers,
Duncan.  

Duncan Lawie
DBE - Oracle.

"There will always be plenty of things to compute in the detailed affairs of millions of people doing complicated things." -- Vannevar Bush, As We May Think; Atlantic Monthly - July 1945.


From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Schultz, Charles Sent: 26 June 2006 15:59
To: Hallas, John, Tech Dev; oracle-l_at_freelists.org Subject: RE: X$ksmsp (OSEE 10.2.0.2 on Solaris 8)

Sorry, let me clarify. We have thousands of entries in ksmsp as well, but I was under the impression that 1 row = 1 contiguous chunk. Sorry for the confusion.


From: Hallas, John, Tech Dev [mailto:John.Hallas_at_gb.vodafone.co.uk] Sent: Monday, June 26, 2006 9:57 AM
To: Schultz, Charles; oracle-l_at_freelists.org Subject: RE: X$ksmsp (OSEE 10.2.0.2 on Solaris 8)

Whilst I was looking at x$ksmsp I came across the following link which provides a useful summary of the x$tables and some interesting queries against some of them.  

http://www.stormloader.com/yonghuang/computer/x$table.html <http://www.stormloader.com/yonghuang/computer/x$table.html>  

Charles, in your database is there only 1 entry in total for that table as I see many thousands of entries (same Oracle version but 2.9 Solaris)  


From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Schultz, Charles Sent: 26 June 2006 15:27
To: oracle-l_at_freelists.org
Subject: X$ksmsp (OSEE 10.2.0.2 on Solaris 8)  

Granted that x$ksmsp is not documented and therefore subject to changes from version to version (or patch to patch), I have an Oracle Support Engineer telling me that one entry in ksmsp might actually show fragmented memory in the case of a memory leak. My understanding, from what I have gleaned from others much smarter than I, was that each row of ksmsp showed one contiguous chunk of memory, be it small or large, FREE or PERM (or something in between). The whole idea of a memory leak causing ksmsp to report a fragmented chunk as one piece is a little disturbing.

Can anyone corroborate or refute this?

Oracle Server Enterprise Edition 10.2.0.2 Solaris 8 (SunOS 5.8) 64-bit

charles schultz
oracle dba
aits - adsd
university of illinois  



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Received on Tue Jun 27 2006 - 07:12:07 CDT

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