Re: AW: Dynamic sampling

From: William Robertson <william_at_williamrobertson.net>
Date: Thu, 11 Nov 2010 07:55:23 +0000
Message-ID: <4CDBA16B.7090109_at_williamrobertson.net>

Well, yes, that could happen if the dynamic sampling level was high and the query was rarely executed or a one-off. Neither of these is necessarily the case when you see a long execution plan and a mention of dynamic sampling in the footnote.

• Original Message -------- Subject: AW: Dynamic sampling From: Petr Novak <Petr.Novak_at_trivadis.com> To: william_at_williamrobertson.net <william_at_williamrobertson.net>, ORACLE-L <oracle-l_at_freelists.org> Date: 11/11/2010 07:40

> But what if the the dynamic sampling consumes more resources the the statements itself ? I have also seen such database. It is better to have correct statistics.
>
> Best Regards,
> Petr
> ________________________________________
> Von: oracle-l-bounce_at_freelists.org [oracle-l-bounce_at_freelists.org]&quot; im Auftrag von&quot;William Robertson [william_at_williamrobertson.net]
> Gesendet: Donnerstag, 11. November 2010 08:02
> Bis: ORACLE-L
> Betreff: Re: Dynamic sampling
>
> What have the number of lines in the plan and the predicates section got to do with dynamic sampling? Are you saying dynamic sampling is a bad thing? It seems like an excellent feature to me.
>
> William Robertson
>
> -------- Original Message --------
> Subject: Dynamic sampling
> From: Hemant K Chitale<hemantkchitale_at_gmail.com>
> To: ORACLE-L<oracle-l_at_freelists.org>
> Date: 11/11/2010 03:43
>>
>> AARGH!
>>
>> What you do when DBMS_XPLAN.DISPLAY_CURSOR shows a 190 line Plan with 205 entries in the Predicates section and then adds "dynamic sampling used".
>>
>> Just venting my frustration.

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Received on Thu Nov 11 2010 - 01:55:23 CST