RE: dbms_stats

Hi John,

Yes, monitoring was set. I wouldn't see anything in *tab_modifications if monitoring wasn't set.

Here's a new twist. What percentage are you comfortable with for valid estimates? I attended a seminar given by Jonathan Lewis a few weeks ago, and he stated that adequate statistics can be gathered using 1% sample. That was great news to me, who has time for huge estimates? OK, so I ran dbms_stats.gather_schema_stats using GATHER EMPTY and estimate_percent set to 1. The rowcounts are way wrong.

(FACP-LISA)>SELECT COUNT(*)
  2 FROM VEGAS_MART
  3 PARTITION (MAY_28_2003);   COUNT(*)

    603826

(FACP-LISA)>select num_rows
  2 from dba_tab_partitions
  3 where table_name = 'VEGAS_MART'
  4 and partition_name = 'MAY_28_2003';

  NUM_ROWS

    595500

(FACP-LISA)> And Jonathan if you happen to read this email, if I am mis-stating what you stated in class please correct me. I am on 8.1.7.4 and that may be the difference.

-----Original Message-----
Sent: Thursday, May 29, 2003 1:36 PM
To: Multiple recipients of list ORACLE-L

Lisa et al,

Am I missing something or did someone ever mention that for STALE to work, one needs to set MONITORING on required objects? Straight from the Fine Manual:

Enabling Automated Statistics Gathering The GATHER STALE option only gathers statistics for tables that have stale statistics and for which you have enabled the MONITORING attribute. To enable monitoring for tables, use the MONITORING keyword of the CREATE TABLE and ALTER TABLE statements, as described in "Designating Tables for Monitoring and Automated Statistics Gathering" on page 8-9.

John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

Great, uplifting music (and best of all commercial-free!) - http://www.klove.com

• The opinions and statements above are entirely my own and not those of my employer or clients **

> -----Original Message-----
> From: Darrell Landrum [mailto:dlandrum_at_zalecorp.com]
> Sent: Wednesday, May 28, 2003 9:30 PM
> To: Multiple recipients of list ORACLE-L
> Subject: Re: dbms_stats broken
>
>
> Lisa,
>
> Wow, you might be saving me from peril right now. I have tested this
> with a small set of tables with no problems (in and 8.1.7.4
> instance).
> I'm preparing to go 'schema' wide in the next week or so for further
> testing prior to implementing in production.
> I'd be very interested in more details of your problems in 8.1.7.4 and
> of course I'll post reports of testing to the list as well.
>
> For starters, here is the code I use to obtain a list of 'stale'
> qualified tables:
> ( For proper credit, I think I got this from asktom.oracle.com)
>
>
> set serverout on size 90000
>
> declare
> l_objList dbms_stats.objecttab;
> begin
> dbms_stats.gather_schema_stats
> ( ownname => '&1',
> options => 'LIST STALE',
> objlist => l_objlist );
> for i in 1 .. l_objlist.count
> loop
> --dbms_output.put_line( l_objlist(i).objtype );
> dbms_output.put_line( l_objlist(i).objname );
> end loop;
> end;
> /
>
>
> And the code to gather stats:
>
> set serverout on size 99000
>
> begin
> dbms_stats.gather_schema_stats(
> ownname=>'&1',
> options=>'GATHER STALE',
> cascade=>TRUE,
> degree=>8,
> granularity=>'ALL',
> method_opt=>'FOR ALL INDEXED COLUMNS SIZE 1'
> );
> end;
> /
>
>
> Thanks,
> Darrell
>
>
> >>> Lisa.Koivu_at_Fairfieldresorts.com 05/28/03 09:24PM >>>
> Hello everyone,
>
> Is anyone using dbms_stats and gather stale or gather auto in 9.2?
> I'm
> trying to use dbms_stats gather schema stats with the stale option and
> it just isn't working in 8.1.7.4. This is documented on Metalink.
> I'd
> love to hear from someone else if this is fixed in 9.2 and if it can
> be
> reliably used.
>
> Thank you
> Lisa Monkey.
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Darrell Landrum
> INET: dlandrum_at_zalecorp.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: John Kanagaraj
  INET: john.kanagaraj_at_hds.com

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-- 
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-- 
Author: Koivu, Lisa
  INET: Lisa.Koivu_at_Fairfieldresorts.com

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