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Re: extended dynamic sampling documentation?

From: Mladen Gogala <mgogala_at_verizon.net>
Date: Fri, 17 Nov 2006 10:20:18 -0500
Message-id: <1163776818l.3842l.0l@medo.noip.com>

On 11/17/2006 10:05:39 AM, ryan_gaffuri_at_comcast.net wrote:
> The documetns/articles on the web are pretty high level. anyone know of any documents that go into more detail. When I look at a tkprof output I see somewhat different dynamic sampling queries when the optimizer level is at 2 (this is 10.2).
>

Ryan, tkprof is intended for analyzing the 10046 trace, aka "sql trace" and nothing else. SQL trace, of course, is next to useless when one is trying to analyze the optimizer behavior. What you need is 10053 trace, level 1 (which actually produces more data then level 2) and the instructions which can be found at Centrex Consulting home page, in Jonathan's book or on Metastink, as a "case study". My favorite is the one by Wolfgang, on Centrex Consulting page, as this was the first one available and I re-read it gazillion times by now. You can change dynamic sampling at the session level and analyze the output with the different levels of optimizer_dynamic_sampling. This is the method one employs when dealing with dilemmas like yours.

-- 
Mladen Gogala
http://www.mladen-gogala.com

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Received on Fri Nov 17 2006 - 09:20:18 CST

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