Re: Trace file does not list detailed timings

  • From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
  • To: "Cary Millsap" <cary.millsap@xxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Sat, 28 Jan 2006 21:29:18 -0000

Had to use 3009359.8 to find it on Metalink

I see that it is "higher CPU use if sql_trace = true",
fixed in - possibly the fix was to stop sql_trace
from enabling _rowsource_execution_statistics.


Jonathan Lewis
The Co-operative Oracle Users' FAQ
Cost Based Oracle: Fundamentals
Public Appearances - schedule updated 10th Jan 2006

----- Original Message ----- From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
To: <jonathan@xxxxxxxxxxxxxxxxxx>; <oracle-l@xxxxxxxxxxxxx>
Sent: Saturday, January 28, 2006 7:55 PM
Subject: RE: Trace file does not list detailed timings

Be aware of bug 3009359.

Cary Millsap Hotsos Enterprises, Ltd. Nullius in verba

Hotsos Symposium 2006 / March 5-9 / Dallas
Visit for curriculum and schedule details...

-----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jonathan Lewis Sent: Friday, January 27, 2006 4:43 PM To: oracle-l@xxxxxxxxxxxxx Subject: Re: Trace file does not list detailed timings

Is this a case of: 9i and It used to show stats when I switched on SQL_TRACE, but it doesn't any more after an upgrade.

If so, then it's a change in default behaviour.  In earlier
versions of 9, when you enabled sql_trace, you implicitly
enabled "_rowsource_execution_statistics". The most
recent versions don't do this. If you want them, then
   alter session set "_rowsource_execution_statistics"=true;

The cost is significant in some classes of query - nested
loops seem to be the worst.  I have an example where
the CPU time goes up by a factor of three when stats
are on.


Jonathan Lewis

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