Lex, I disagree with your disagreement, but let me qualify. Oracle "discourages" collecting statistics gathering "in most cases" per note 35272.1, as mentioned in my previous posting. The qualify this to say that in certain larger implementations, statistics can be selectively applied to certain dictionary objects, but even then, only with internal Oracle guidance. Therefore, let's conclude, that for the general populace, collecting statistics for the ENTIRE schema is not recommended. Oracle also mentions, in this article, that they have no plans to change this. We have both Oracle8i and oracle9i implementations in my shop. I assure you we will immediately notice severe performance degradation if stats are applied to SYS. It's already happened...for 95% of Oracle installations, it's my opinion that they'd be better off staying away from it. Michael Fontana Sr. DBA NTT/Verio -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Lex de Haan Sent: Thursday, July 29, 2004 2:08 PM To: oracle-l@xxxxxxxxxxxxx Subject: RE: SHOULD WE ANALYZE 9.2 SYS tables? I must disagree here. it is true that Oracle never actively encouraged customers to gather statistics for the SYS schema in Oracle9i, but it certainly cannot ruin your performance. Oracle also doesn't explicitly forbid you to gather DD statistics. you have to go back further in time (Oracle8i) to get into trouble with data dictionary statistics. I discussed this with the optimizer development team (when I was still inside Oracle) and they told me that there are no reasons at all *not* to gather statistics on the SYS schema. In other words, feel free. as you probably know, various Oracle9i DD views actually have hints in their definitions, kicking in CBO anyway ... Kind regards, Lex. --------------------------------------------- visit my website at http://www.naturaljoin.nl --------------------------------------------- -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Juan Carlos Reyes Pacheco Sent: Thursday, July 29, 2004 19:42 To: oracle-l@xxxxxxxxxxxxx Subject: Re: SHOULD WE ANALYZE 9.2 SYS tables? Hi Larry SYS schema don't need be analyzed, using tom kyte's word "it's magical" and must not be analyzed if you got statistics in sys, you can ruin it's performance. sys schema don't have to be touched, this means don't create user tables in sys, etc. Juan Carlos Reyes Pacheco OCP -------Original Message------- From: oracle-l@xxxxxxxxxxxxx Date: 07/29/04 14:25:41 To: 'oracle-l@xxxxxxxxxxxxx' Subject: SHOULD WE ANALYZE 9.2 SYS tables? I had a question about a problem with 9.2 V$ views where a RULE hint helped V$LOCK tremendously. Someone suggested Analyzing the SYS tables. IS everyone doing that now or is there considerable reticence? I didn't get a much current information when I searched the FAQ or Google Has anyone experienced a downside? Is anyone doing some of the tables but not all? Thanks Larry Wolfson ********************************************************************** The information contained in this communication is confidential, is intended only for the use of the recipient named above, and may be legally privileged. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please re-send this communication to the sender and delete the original message or any copy of it from your computer system. 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