Re: Estimate versus Compute

From: Michael McMullen <ganstadba_at_hotmail.com>
Date: Mon, 25 Jul 2005 14:27:42 -0400
Message-ID: <BAY103-DAV1408C0373673C1A4DF19EA6CA0@phx.gbl>

I read somewhere, can't remember where, that when estimating one should use an estimate of 1 percent because anything else means all blocks get visited. I have found the greatest time reducer is only analyzing for all indexed columns with estimate_percent=>1.

Mike
----- Original Message -----

From: Powell, Mark D
To: Oracle-L_at_freelists.org
Sent: Monday, July 25, 2005 12:59 PM
Subject: RE: Estimate versus Compute

We have always used an estimate with a row count since Oracle managed to provide a working version of the command.

analyze table o.t estimate statistics sample 150000 rows;

You can do the same with dbms_stats.

HTH -- Mark D Powell --

--

http://www.freelists.org/webpage/oracle-l Received on Mon Jul 25 2005 - 13:30:52 CDT