Re: What are the implications of running dbms_stats and analyze compute?

  • From: Wolfgang Breitling <breitliw@xxxxxxxxxxxxx>
  • To: achoto@xxxxxxxxxxxx
  • Date: Tue, 09 Aug 2005 09:41:02 -0600

Try
DBMS_STATS.GATHER_TABLE_STATS(OWNNAME => <'owner'>, TABNAME => <'table_name'>, CASCADE => TRUE);


i.e. without the histograms on every column. That is equivalent to the analyze table xxx compute statistics;

Ana Choto wrote:

We have migrated our datawarehouse to 9.2.0.6 from 8.1.7.4.  Since the
upgrade we experienced some performance degradation.  We run a daily job to
analyze the datawarehouse schemas using dbms_stats.  But, queries that ran
in seconds were taking hours to run.  So, the developers started
reanalyzing the tables with 'analyze compute', which resulted on the
queries running at the same level they were on 8i.

The only thing, is that now, some tables have been analyzed with dbms_stats
and others with 'analyze compute'.  Is there a problem by doing this?

Oracle support asked me to run the dbms_stats job with the 'exec
DBMS_STATS.GATHER_TABLE_STATS(OWNNAME => <'owner'>, TABNAME =>
<'table_name'> , CASCADE => TRUE, method_opt => 'FOR ALL COLUMNS SIZE
200');' command.  But this didn't help, so the developers just reanalyze
the tables with 'analyze compute' command.

Thanks

Ana E. Choto
American University
e-Operations - Information Technology
Phone (202) 885-2275
Fax      (202) 885-2224

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-- Regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com
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