Re: log_duration is redundant, no? - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: log_duration is redundant, no?
Date
Msg-id 200609072352.k87NqeD20056@momjian.us
Whole thread Raw
In response to Re: log_duration is redundant, no?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: log_duration is redundant, no?  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-hackers
Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > Well, except for bind, all the log output display is zero cost, just a
> > printf(), as I remember.  The only cost that is significant, I think, is
> > the timing of the query, and that is happening for all the setttings
> > discussed.
> 
> On a machine with slow gettimeofday(), measuring duration at all is
> going to hurt, but apparently that is not Guillaume's situation ---
> what's costing him is sheer log volume.  And remember that the
> slow-gettimeofday problem exists mainly on cheap PCs, not server-grade
> hardware.  Based on his experience I'm prepared to believe that there
> is a use-case for logging just the duration for short queries.
> 
> It seems like we should either remove the separate log_duration boolean
> or make it work as he suggests.  I'm leaning to the second answer now.
> What's your vote?

#2, I think, but I am confused if you don't know the query, how valuable
is the log_duration.

--  Bruce Momjian   bruce@momjian.us EnterpriseDB    http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


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