Re: log_min_duration_statement versus log_statement

Josh Berkus wrote:
> Bruce,
>
> > OK, what if we change the documentaiton to be:
> >
> >     log_min_duration_statement = 1000 # Log all statements whose
> >                      # execution time exceeds the value, in
> >                      # milliseconds.  -1 disables. Zero logs
> >                      # all statements and their durations.
> >
> > I think you are confused because log_min_duration_statement is really
> > about _when_ to log (duration > ? ms), and what to log (the statement).
>
> No, I see what Christian is complaining about.   If one sets
> log_statement="All", then all statements will be logged regardless of
> duration or the setting in log_min_duration_statement.  So it should
> actually read:
>
>      log_min_duration_statement = 1000 # Log all statements whose
>                       # execution time exceeds the value, in
>                       # milliseconds.  -1 disables. This is in addition to
>                          # any statements logged according to
> log_statement.
>
> I'm with Christian on wanting to change the behavior so that it does what
> the comments says it does currently, but I don't think we'll get that done
> today.

I have updated the documentation to be clearer that this is a complex
setting.  The old docs were not very clear on this point.

Attached and applied.

I don't know we can ever combine this with log_statement and
log_duration because log_statement prints when the statement starts, not
when it completes.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v
retrieving revision 1.332
diff -c -c -r1.332 runtime.sgml
*** doc/src/sgml/runtime.sgml    26 Jun 2005 19:16:04 -0000    1.332
--- doc/src/sgml/runtime.sgml    1 Jul 2005 13:25:51 -0000
***************
*** 2628,2643 ****
        </indexterm>
         <listitem>
          <para>
!          Sets a minimum statement execution time (in milliseconds)
!          that causes a statement to be logged.  All SQL statements
!          that run for the time specified or longer will be logged with
!          their duration.  Setting this to zero will print
!          all queries and their durations.  Minus-one (the default)
!          disables the feature.  For example, if you set it to
!          <literal>250</literal> then all SQL statements that run 250ms
!          or longer will be logged.  Enabling this option can be
!          useful in tracking down unoptimized queries in your applications.
!          Only superusers can change this setting.
          </para>
         </listitem>
        </varlistentry>
--- 2628,2644 ----
        </indexterm>
         <listitem>
          <para>
!          Logs the statement and its duration on a single log line if its
!          duration is greater than or equal to the specified number of
!          milliseconds. Setting this to zero will print all statements
!          and their durations. Minus-one (the default) disables the
!          feature. For example, if you set it to <literal>250</literal>
!          then all SQL statements that run 250ms or longer will be
!          logged. Enabling this option can be useful in tracking down
!          unoptimized queries in your applications. This setting is
!          independent of <varname>log_statement</varname> and
!          <varname>log_duration</varname>. Only superusers can change
!          this setting.
          </para>
         </listitem>
        </varlistentry>
Index: src/backend/utils/misc/postgresql.conf.sample
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RCS file: /cvsroot/pgsql/src/backend/utils/misc/postgresql.conf.sample,v
retrieving revision 1.148
diff -c -c -r1.148 postgresql.conf.sample
*** src/backend/utils/misc/postgresql.conf.sample    26 Jun 2005 03:03:41 -0000    1.148
--- src/backend/utils/misc/postgresql.conf.sample    1 Jul 2005 13:25:53 -0000
***************
*** 227,233 ****
                   #   debug5, debug4, debug3, debug2, debug1,
                   #   info, notice, warning, error, panic(off)

! #log_min_duration_statement = -1 # -1 is disabled, in milliseconds.

  #silent_mode = false         # DO NOT USE without syslog or redirect_stderr

--- 227,234 ----
                   #   debug5, debug4, debug3, debug2, debug1,
                   #   info, notice, warning, error, panic(off)

! #log_min_duration_statement = -1 # -1 is disabled, 0 logs all statements
!                  # and their durations, in milliseconds.

  #silent_mode = false         # DO NOT USE without syslog or redirect_stderr