Re: dbms_stats and incorrect statistics

From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Thu, 31 May 2007 08:13:02 -0600
Message-Id: <20070531141254.1C9FB6EAB98@turing.freelists.org>

I bet DATEFIRED has 5842 NULLs - or had at the time you gathered the stats.

At 01:12 AM 5/31/2007, Ronnie Doggart wrote:
>Hi,
>
>Oracle 9.2.0.8 on Oracle Enterprise Linux
>
>We looking at reducing the amount of time taken to gather statistics
>on our production database. Initially we where using
>dbms_stats.gather_schema_stats with compute and cascade=>true. We
>want to use an estimate on the tables and compute on the indexes so
>we split the analysis up. However during testing we noticed that
>some tables had stats that where inconsistent. For instance using
>dbms_stats.gather_table_stats with compute the number of rows
>reported as sampled varied on a column per column basis in the same table e.g
>
>TABLE_NAME COLUMN_NAME
>DATA_TYPE NUM_DISTINCT SAMPLE_SIZE
>LGNCC_ESCRULE ESCRULESTATUS NUMBER
> 4 14563
>LGNCC_ESCRULE DATEFIRED
>DATE 4896 8721
>
>Does a compute not read all the rows in a table for each column, the
>table above has 14563 rows.

Regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com

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Received on Thu May 31 2007 - 09:13:02 CDT