Re: dbms_stats.gather_system_stats

From: Connor McDonald <hamcdc_at_yahoo.co.uk>
Date: Wed, 8 Sep 2004 01:52:39 +0100 (BST)
Message-ID: <20040908005239.93933.qmail@web86902.mail.ukl.yahoo.com>

Although I'd argue that (more often than not) even slightly dubious system stats may more than make up for deficiencies in init.ora settings, the most common one being db_file_multiblock_read_count. I've seen many a place where the requested value (ie init.ora) and the observed value (from system stats) are wildly different.

Cheers
Connor

• Wolfgang Breitling <breitliw_at_centrexcc.com> wrote:
  > Gathering system stats gives the optimizer more information about the
  > current workload mix and the capabilities of the system ( cpu speed, IO
  > performance). In general this should lead to better access plans and better
  > performance and I have heard that people have had good success with it.
  > However, any changes that impact the optimizer should be tested thoroughly
  > because there could be nasty surprises. If you have a mixed workload, e.g.
  > OLTP during the day and batch during off-hours, you should have separate
  > system statistics for each workload and switch them in as appropriate.
  >
  

  ---

Connor McDonald
Co-author: "Mastering Oracle PL/SQL - Practical Solutions" ISBN: 1590592174 web: http://www.oracledba.co.uk
web: http://www.oaktable.net
email: connor_mcdonald_at_yahoo.com

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Received on Tue Sep 07 2004 - 19:48:51 CDT