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Date: Thu, 3 Mar 2011 12:12:25 -0500
Message-ID: <AANLkTimR0yDCa_Mqw_24kmBZTAJVNViiR=hn50QHg=Dr@mail.gmail.com>
Subject: Re: should I analyze system statistics on ORACLE 10GR2?
From: Wayne Smith <wts@maine.edu>
To: mccdba1@yahoo.com
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This was important to our PeopleSoft/Oracle 10.2.0.3 DB performance.  See
bug 5103126.8 and note 375944.1 (fixed in 11g, as I recall).  Again, as I
recall, that when statistics were deleted from 3 objects in SYS, performance
of certain functions were dramatically improved.   Cheers, Wayne

On Wed, Feb 16, 2011 at 2:56 PM, 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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This was important to our PeopleSoft/Oracle 10.2.0.3 DB performance.=A0 See=
 bug 5103126.8 and note 375944.1 (fixed in 11g, as I recall).=A0 Again, as =
I recall, that when statistics were deleted from 3 objects in SYS, performa=
nce of certain functions were dramatically improved.=A0=A0 Cheers, Wayne<br=
>
<br><div class=3D"gmail_quote">On Wed, Feb 16, 2011 at 2:56 PM, dba1 mcc <s=
pan dir=3D"ltr">&lt;<a href=3D"mailto:mccdba1@yahoo.com">mccdba1@yahoo.com<=
/a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:=
0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
I saw a ORACLE document &quot;Performance Tuning Guide for Siebel CRM<br>
Application on Oracle Part I - Cost-Based Optimization Guide&quot; =A0On th=
is 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_costing, a mechanism that allows the CPU cost =
of an operation to be included as part of the overall estimate. This featur=
e is enabled in 9i only if you collect system statistics. This feature in 1=
0g is enabled by default. Oracle Database 10g gathers two types of system s=
tatistics - statistics captured without a workload (noworkload) and statist=
ics 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 l=
owest estimated cost relative to other 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 document say you need &quot;analyze system statis=
tics&quot; to avoid stange thing happen.<br>
<br>
Can Anyone tell me should I or Should NOT &#39;analyze system statistics&qu=
ot;?<br>
Thanks.<br>
<font color=3D"#888888"><br>
<br>
<br>
<br>
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</font></blockquote></div><br>

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