RE: V$SGASTAT
- From: "Powell, Mark" <mark.powell2@xxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 11 Mar 2014 17:43:30 +0000
Stephan, I believe that part of the allocated memory that is shown as used by
v$sgastat can in fact be freed if determined necessary by Oracle. I think you
can see this via sys.x$ksmsp.
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Uzzell, Stephan
Sent: Tuesday, March 11, 2014 9:46 AM
To: oracle-l@xxxxxxxxxxxxx
Cc: Uzzell, Stephan
Subject: V$SGASTAT
Hi all,
We recently had an issue with an undersized shared pool. We've increase the
size of the shared pool and think this should be resolved. Our customer,
however, is freaking out and wants to monitor this.
I've been looking at v$sgastat hoping this would provide the information, but I
don't quite understand how the view works. Testing against 11.2.0.3.7 on
OEL6x64.
Shared_pool_size is set at 256MB for each instance in this RAC. Yet when I try
to sum up either the free memory value or the non-free values, I get results
far larger than that:
SQL> select
2 type
3 , round( sum( bytes /1024 /1024 ) ) MB
4 from
5 (
6 select
7 case when name = 'free memory' then 'FREE' else 'USED' end
type
8 , bytes
9 from
10 v$sgastat
11 where
12 pool = 'shared pool'
13 )
14 group by
15 type
16 /
TYPE MB
---- ----------
USED 3760
FREE 1744
Am I completely misunderstanding how this is supposed to work? Is there some
way to monitor shared pool usage?
Stephan Uzzell
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