Re: SGA Free memory

On a related note, have you guys noticed the very large memories on a "round" address with KSMCHCOM = 'permanent memor' and KSMCHCLS = 'perm' ?

SQL> select * from sys.x_$ksmsp where KSMCHCOM = 'permanent memor' and KSMCHCLS = 'perm' and ksmchsiz > 10000000;

ADDR                   INDX    INST_ID   KSMCHIDX   KSMCHDUR KSMCHCOM 
       KSMCHPTR           KSMCHSIZ KSMCHCLS   KSMCHTYP KSMCHPAR
---------------- ---------- ---------- ---------- ----------
---------------- ---------------- ---------- -------- ----------
----------------
0000002A97C66E18         13          1          1          1 permanent
memor  00000001BC0CD000   15899128 perm              0 00
0000002A97C669F8         25          1          1          1 permanent
memor  00000001BB0CD000   15596208 perm              0 00
0000002A97C66790         32          1          1          1 permanent
memor  00000001BA0CD000   15933896 perm              0 00
0000002A97C66370         44          1          1          1 permanent
memor  00000001B90CD000   15933896 perm              0 00
0000002A97C67388         90          1          1          1 permanent
memor  00000001B80CD000   13792800 perm              0 00
0000002A97C68A28        117          1          1          1 permanent
memor  00000001B70CD000   15902000 perm              0 00
0000002A97C68870        122          1          1          1 permanent
memor  00000001B60CD000   15851552 perm              0 00
0000002A97C68660        128          1          1          1 permanent
memor  00000001B50CD000   15109080 perm              0 00
0000002A97C68030        146          1          1          1 permanent
memor  00000001B40CD000   15886048 perm              0 00
0000002A97C692B0        185          1          1          1 permanent
memor  00000001B30CD000   14680096 perm              0 00
0000002A97BF2C78       6093          1          1          1 permanent
memor  00000001AF0CD000   15937376 perm              0 00

This looks to me like some kind of reserved memory, as I remember seeing a couple of these disappear in favor of other areas.

Jonathan what other articles would you recommend for shared pool insides ?

--
Christo Kutrovsky
Senior Database/System Administrator
The Pythian Group



On 2/11/06, Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk> wrote:


>

> Thanks for the reference - interesting paper.

>

> Regards

>

> Jonathan Lewis

> http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis

>

> The Co-operative Oracle Users' FAQ

> http://www.jlcomp.demon.co.uk/faq/ind_faq.html

>

> Cost Based Oracle: Fundamentals

> http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

>

>

> ----- Original Message -----

> From: "Luca Canali" <Luca.Canali_at_cern.ch>

> To: <oracle-l_at_freelists.org>

> Sent: Friday, February 10, 2006 8:15 AM

> Subject: RE: SGA Free memory

>

>

> Hi Jonathan,

>

> >    loop

> >        detach some items from end of library cache LRU

> >        distribute items to shared pool free list - coalescing where

> possible

> >        check for large enough chunk on free list

> >        return if allocation succeeds

> >    end loop

> >

> >    There may be a limit on the number of times round the loop -

>

> Apparently the limit is 5 iterations (see Russell Green, OOW Sep. 2005)

>

> Regards,

> Luca

>

> -----------

> Luca Canali

> Information Technology Department

> European Organization for Nuclear Research

> CERN

> CH-1211 Geneva 23

> --

> http://www.freelists.org/webpage/oracle-l

>

>

>

>

> --

> http://www.freelists.org/webpage/oracle-l

>

>

>



--
Christo Kutrovsky
Senior Database/System Administrator
The Pythian Group
--
http://www.freelists.org/webpage/oracle-l