Really deleting system statistics?

From: Peter Alteheld <palteheld_at_yahoo.de>
Date: Wed, 11 May 2005 11:03:08 +0200 (CEST)
Message-ID: <20050511090308.3201.qmail@web26503.mail.ukl.yahoo.com>

Hi list,  

in 10.1.0.3 I tried to delete system statistics with  

exec DBMS_STATS.DELETE_SYSTEM_STATS;  

No error. In sys.aux_stats$ the 'Flag' goes from 1 to 0. And values for mreadtim,sreadtim.. stay set. (And I cannot set them to NULL with SET_SYSTEM_STATS). After flushing buffer cache and shared pool the cost calculation (explain plan) still seems to use the 'deleted' statistics same costs. I cannot reproduce the numbers from before I had any system statistics gathered - and by then they were reproducible.  

Any idea how to convince the optimizer not to use the deleted statistics?  

Peter                 

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http://www.freelists.org/webpage/oracle-l Received on Wed May 11 2005 - 05:07:39 CDT