Re: Trace file does not list detailed timings



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

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----- Original Message ----- From: "Tanel Põder" <tanel.poder.003@xxxxxxx>
To: "ORACLE-L" <oracle-l@xxxxxxxxxxxxx>
Sent: Monday, January 30, 2006 7:37 PM
Subject: Re: Trace file does not list detailed timings


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.


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