The attached patch forces queryless duration log statements to be turned off
in step with the log_statement directive. Without this patch, and with
log_statement = 'mod' and log_duration = true, there is no way to silence
SELECT query duration logging when quieting the logging of SELECT queries.
Note this patch changes the semantics of log_duration from logging the
duration of "every completed statement" to "every completed statement that
satisfies log_statement directive". I argue this semantic change is
justified given 1) the docs themselves recommend turning log_statement
sufficiently up to be able to make this mapping, and 2) I can see it being
quite common that folks only want to log queries (and durations) that
change the database, while I fail to see the usefulness of queryless
durations (and I'm trying to scratch my own itch with a small effort).
It's possible someone else feels strongly about their queryless durations
for reasons I cannot imagine. If so, then another more conservative
approach may be in order.
Note also this patch is independent of queries and durations logged due to
the log_min_duration_statement directive. If, for example, log_statement =
'all', log_min_duration_statement = 1 (ms), and a SELECT query takes longer
than 1ms, it's duration will be logged twice, with the 2nd log entry
including the statement with the duration.
Ed
Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.284
diff -C1 -r1.284 runtime.sgml
*** doc/src/sgml/runtime.sgml 26 Sep 2004 22:51:49 -0000 1.284
--- doc/src/sgml/runtime.sgml 28 Sep 2004 02:19:16 -0000
***************
*** 2305,2313 ****
<para>
! Causes the duration of every completed statement to be logged.
! To use this option, it is recommended that you also enable
! <varname>log_statement</> and if not using <application>syslog</>
! log the PID using <varname>log_line_prefix</> so that you
! can link the statement to the duration using the process
! ID. The default is off. Only superusers can turn off this
! option if it is enabled by the administrator.
</para>
--- 2305,2314 ----
<para>
! Causes the duration of every completed statement which satisfies
! <varname>log_statement</> directive to be logged.
! When using this option, if you are not using <application>syslog</>,
! it is recommended that you log the PID or session ID using
! <varname>log_line_prefix</> or log the session ID so that you can
! link the statement to the duration using the process ID or session
! ID. The default is off. Only superusers can turn off this option
! if it is enabled by the administrator.
</para>
Index: src/backend/tcop/postgres.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/tcop/postgres.c,v
retrieving revision 1.433
diff -C1 -r1.433 postgres.c
*** src/backend/tcop/postgres.c 26 Sep 2004 00:26:25 -0000 1.433
--- src/backend/tcop/postgres.c 28 Sep 2004 02:19:19 -0000
***************
*** 83,84 ****
--- 83,87 ----
+ /* flag noting if the statement satisfies log_statement directive */
+ bool loggable_statement;
+
/* GUC variable for maximum stack depth (measured in kilobytes) */
***************
*** 465,469 ****
--- 468,476 ----
+ loggable_statement = false;
if (log_statement == LOGSTMT_ALL)
+ {
ereport(LOG,
(errmsg("statement: %s", query_string)));
+ loggable_statement = true;
+ }
***************
*** 503,504 ****
--- 510,512 ----
(errmsg("statement: %s", query_string)));
+ loggable_statement = true;
break;
***************
*** 514,515 ****
--- 522,524 ----
(errmsg("statement: %s", query_string)));
+ loggable_statement = true;
break;
***************
*** 1005,1007 ****
! if (save_log_duration)
ereport(LOG,
--- 1014,1023 ----
! /*
! * If log_duration = true, don't log duration unless statement
! * statement also satifies log_statement directive. Otherwise,
! * the duration statements are devoid of context without their
! * query having been logged. Note the statement still may be
! * below due to log_min_duration_statement directive.
! */
! if (loggable_statement && save_log_duration)
ereport(LOG,
---------------------------(end of broadcast)---------------------------
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