Re: Estimate versus Compute

  • From: "Michael McMullen" <ganstadba@xxxxxxxxxxx>
  • To: <mark.powell@xxxxxxx>, <Oracle-L@xxxxxxxxxxxxx>
  • Date: Mon, 25 Jul 2005 14:27:42 -0400

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@xxxxxxxxxxxxx
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 --





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