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Date: Fri, 4 Mar 2011 10:33:19 +0530
Message-ID: <AANLkTikm+VhUQ3M5f0v26jk6YQv_K_PuBYUQGnMN+F9R@mail.gmail.com>
Subject: Re: should I analyze system statistics on ORACLE 10GR2?
From: Subodh Deshpande <deshpande.subodh@gmail.com>
To: mccdba1@yahoo.com
Cc: oracle-l@freelists.org, oracle-db-l@groups.ittoolbox.com
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if you using cost based optimizer then you should collect stats..
I think...over a period earlier stats can be purged
thanks....subodh


On 17 February 2011 01:26, dba1 mcc <mccdba1@yahoo.com> wrote:

> I saw a ORACLE document "Performance Tuning Guide for Siebel CRM
> Application on Oracle Part I - Cost-Based Optimization Guide"  On this
> article it say "don't analyze system statistics":
>
> ==================================================
> System Optimizer Statistics
> In 9i, Oracle introduced cpu_costing, a mechanism that allows the CPU cost
> of an operation to be included as part of the overall estimate. This feature
> is enabled in 9i only if you collect system statistics. This feature in 10g
> is enabled by default. Oracle Database 10g gathers two types of system
> statistics - statistics captured without a workload (noworkload) and
> statistics captured with a workload. In addition to CPU cost, disk I/O and
> memory utilization are also captured, to ensure that CBO picks the plan with
> the lowest estimated cost relative to other plans.
> Many Oracle DBAs attempt to leverage system optimizer statistics for
> further tuning of Siebel CRM application. Such actions may cause
> unpredictable degradation in performance of certain Siebel CRM application
> views and queries, and are strongly discouraged. We recommend that DBAs
> refrain from collecting system optimizer statistics, or altering any Oracle
> default settings pertaining to systems statistics.
>
> ============================================================
>
> I also see another ORACLE document say you need "analyze system statistics"
> to avoid stange thing happen.
>
> Can Anyone tell me should I or Should NOT 'analyze system statistics"?
> Thanks.
>
>
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>


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DO NOT FORGET TO SMILE TODAY
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<div>if you using cost based optimizer then you should collect stats..</div=
>
<div>I think...over a period earlier stats can be purged</div>
<div>thanks....subodh</div>
<div><br>=A0</div>
<div class=3D"gmail_quote">On 17 February 2011 01:26, dba1 mcc <span dir=3D=
"ltr">&lt;<a href=3D"mailto:mccdba1@yahoo.com">mccdba1@yahoo.com</a>&gt;</s=
pan> wrote:<br>
<blockquote style=3D"BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex=
; PADDING-LEFT: 1ex" class=3D"gmail_quote">I saw a ORACLE document &quot;Pe=
rformance Tuning Guide for Siebel CRM<br>Application on Oracle Part I - Cos=
t-Based Optimization Guide&quot; =A0On this article it say &quot;don&#39;t =
analyze system statistics&quot;:<br>
<br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D<br>System Optimizer Statistics<br>In 9i, Oracle introduced cpu_costi=
ng, a mechanism that allows the CPU cost of an operation to be included as =
part of the overall estimate. This feature is enabled in 9i only if you col=
lect system statistics. This feature in 10g is enabled by default. Oracle D=
atabase 10g gathers two types of system statistics - statistics captured wi=
thout a workload (noworkload) and statistics captured with a workload. In a=
ddition to CPU cost, disk I/O and memory utilization are also captured, to =
ensure that CBO picks the plan with the lowest estimated cost relative to o=
ther plans.<br>
Many Oracle DBAs attempt to leverage system optimizer statistics for furthe=
r tuning of Siebel CRM application. Such actions may cause unpredictable de=
gradation in performance of certain Siebel CRM application views and querie=
s, and are strongly discouraged. We recommend that DBAs refrain from collec=
ting system optimizer statistics, or altering any Oracle default settings p=
ertaining to systems statistics.<br>
<br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br><br>I also see another ORACLE docum=
ent say you need &quot;analyze system statistics&quot; to avoid stange thin=
g happen.<br><br>Can Anyone tell me should I or Should NOT &#39;analyze sys=
tem statistics&quot;?<br>
Thanks.<br><font color=3D"#888888"><br><br><br><br>--<br><a href=3D"http://=
www.freelists.org/webpage/oracle-l" target=3D"_blank">http://www.freelists.=
org/webpage/oracle-l</a><br><br><br></font></blockquote></div><br><br clear=
=3D"all">
<br>-- <br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D<br>DO NOT FORGET TO SMILE TODAY<br>=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D<br>

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