should I analyze system statistics on ORACLE 10GR2?
From: dba1 mcc <mccdba1_at_yahoo.com>
Date: Wed, 16 Feb 2011 11:56:25 -0800 (PST)
Message-ID: <341086.40642.qm_at_web120509.mail.ne1.yahoo.com>
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.
Date: Wed, 16 Feb 2011 11:56:25 -0800 (PST)
Message-ID: <341086.40642.qm_at_web120509.mail.ne1.yahoo.com>
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-lReceived on Wed Feb 16 2011 - 13:56:25 CST