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Re: Trace file does not list detailed timings

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Mon, 30 Jan 2006 19:46:20 -0000
Message-ID: <001d01c625d5$d7c87c20$0200a8c0@Primary>

I did a couple of quick checks of sample frequency with one of my stress tests a
few months ago.

without sampling ca. 2 seconds
with default sampling (128) ca. 6 seconds with sample size = 1 ca. 10 seconds

Obviously dependent on the number of times a line of the execution plan is started, so most sensitive to nested loop types of activity.

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html Cost Based Oracle: Fundamentals

http://www.jlcomp.demon.co.uk/appearances.html Public Appearances - schedule updated 10th Jan 2006

> Hi,
>
>> it in the session when you enable sql_trace. The only problem is that you can
>> enable tracing for a session from a different session, but you can not change
>> statistics_level for a different session. At least I do not know of a way.
>> There are set_int_paramt_in_session and set_bool_param_in_session, but no
>> set_char_param_in_session.
>
> Jonathan mentioned the _rowsource_execution_statistics parameter, this is a
> boolean parameter and could be set with dbms_system.set_bool_param_in_session.
>
> Btw, from 10g there is a _rowsource_statistics_sampfreq parameter, which could
> control the performance impact (and accuracy) of gathering rowsource
> statistics. I haven't done any tests with it though...
>
> Tanel.
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>

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Received on Mon Jan 30 2006 - 13:46:20 CST

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