RE: library cache get hit ratio
- From: "Zelli, Brian" <Brian.Zelli@xxxxxxxxxxxxxxx>
- To: 'Andrew Kerber' <andrew.kerber@xxxxxxxxx>, "troach@xxxxxxxxx" <troach@xxxxxxxxx>
- Date: Thu, 2 Dec 2010 15:36:04 -0500
So if I have sga_target set, then I shouldn't be messing around with shared
pool?
ciao,
Brian
________________________________
From: Andrew Kerber [mailto:andrew.kerber@xxxxxxxxx]
Sent: Thursday, December 02, 2010 3:07 PM
To: troach@xxxxxxxxx
Cc: Zelli, Brian; oracle-l-freelists
Subject: Re: library cache get hit ratio
There are some bugs with cursor sharing, but try setting cursor_sharing=force
and see what that does to your hit ratio. If you dont get a bunch of ora-600's,
it should help.
On Thu, Dec 2, 2010 at 1:56 PM, Thomas Roach
<troach@xxxxxxxxx<mailto:troach@xxxxxxxxx>> wrote:
It really depends.
Do you have a large amount of SQL statements where the only difference is the
values in the where clause? If so, look at bind variables or setting the
cursor_sharing parameter if you can't change the code.
If there are many SQL statements that are run (and many run more than once),
then increasing the shared pool size can help if it is too small.
If there are just a bunch of ad-hoc queries that are run once, then you are
going to have a lower hit ratio.
These are just a few examples.
It all really just depends on your workload really.
On Thu, Dec 2, 2010 at 2:45 PM, Zelli, Brian
<Brian.Zelli@xxxxxxxxxxxxxxx<mailto:Brian.Zelli@xxxxxxxxxxxxxxx>> wrote:
I am seeing my lib cache get hit ratio at 60-70%. What I read says it should
be above 90%. It says if it is low to increase shared pool size. I doubled it
and still see no difference.
Anything else to change?
It also says to improve the efficiency of the app code but the developers are
using a tool that creates the app and are clueless as to what's under the hood.
ciao,
Brian
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