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

Ana,

Did you run explain plans for the offending sql's? We need to see what the optimizer chose to help you.

Tom

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Ana Choto Sent: Tuesday, August 09, 2005 11:24 AM
To: oracle-l_at_freelists.org
Subject: What are the implications of running dbms_stats and analyze compute?

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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http://www.freelists.org/webpage/oracle-l Received on Tue Aug 09 2005 - 10:44:06 CDT