Re: should I analyze system statistics on ORACLE 10GR2?

  • From: Subodh Deshpande <deshpande.subodh@xxxxxxxxx>
  • To: mccdba1@xxxxxxxxx
  • Date: Fri, 4 Mar 2011 10:33:19 +0530

if you using cost based optimizer then you should collect stats..
I think...over a period earlier stats can be purged

On 17 February 2011 01:26, dba1 mcc <mccdba1@xxxxxxxxx> 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.
> --


Other related posts: