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><H1
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><A
NAME="RUNTIME-CONFIG-STATISTICS"
>18.9. Run-time Statistics</A
></H1
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-STATISTICS-COLLECTOR"
>18.9.1. Query and Index Statistics Collector</A
></H2
><P
> These parameters control server-wide statistics collection features.
When statistics collection is enabled, the data that is produced can be
accessed via the <TT
CLASS="STRUCTNAME"
>pg_stat</TT
> and
<TT
CLASS="STRUCTNAME"
>pg_statio</TT
> family of system views.
Refer to <A
HREF="monitoring.html"
>Chapter 27</A
> for more information.
</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="GUC-TRACK-ACTIVITIES"
></A
><TT
CLASS="VARNAME"
>track_activities</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)</DT
><DD
><P
> Enables the collection of information on the currently
executing command of each session, along with the time when
that command began execution. This parameter is on by
default. Note that even when enabled, this information is not
visible to all users, only to superusers and the user owning
the session being reported on, so it should not represent a
security risk.
Only superusers can change this setting.
</P
></DD
><DT
><A
NAME="GUC-TRACK-ACTIVITY-QUERY-SIZE"
></A
><TT
CLASS="VARNAME"
>track_activity_query_size</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)</DT
><DD
><P
> Specifies the number of bytes reserved to track the currently
executing command for each active session, for the
<TT
CLASS="STRUCTNAME"
>pg_stat_activity</TT
>.<TT
CLASS="STRUCTFIELD"
>query</TT
> field.
The default value is 1024. This parameter can only be set at server
start.
</P
></DD
><DT
><A
NAME="GUC-TRACK-COUNTS"
></A
><TT
CLASS="VARNAME"
>track_counts</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)</DT
><DD
><P
> Enables collection of statistics on database activity.
This parameter is on by default, because the autovacuum
daemon needs the collected information.
Only superusers can change this setting.
</P
></DD
><DT
><A
NAME="GUC-TRACK-IO-TIMING"
></A
><TT
CLASS="VARNAME"
>track_io_timing</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)</DT
><DD
><P
> Enables timing of database I/O calls. This parameter is off by
default, because it will repeatedly query the operating system for
the current time, which may cause significant overhead on some
platforms. You can use the <A
HREF="pgtesttiming.html"
><SPAN
CLASS="APPLICATION"
>pg_test_timing</SPAN
></A
> tool to
measure the overhead of timing on your system.
I/O timing information is
displayed in <A
HREF="monitoring-stats.html#PG-STAT-DATABASE-VIEW"
>pg_stat_database</A
>, in the output of
<A
HREF="sql-explain.html"
>EXPLAIN</A
> when the <TT
CLASS="LITERAL"
>BUFFERS</TT
> option is
used, and by <A
HREF="pgstatstatements.html"
>pg_stat_statements</A
>. Only superusers can
change this setting.
</P
></DD
><DT
><A
NAME="GUC-TRACK-FUNCTIONS"
></A
><TT
CLASS="VARNAME"
>track_functions</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)</DT
><DD
><P
> Enables tracking of function call counts and time used. Specify
<TT
CLASS="LITERAL"
>pl</TT
> to track only procedural-language functions,
<TT
CLASS="LITERAL"
>all</TT
> to also track SQL and C language functions.
The default is <TT
CLASS="LITERAL"
>none</TT
>, which disables function
statistics tracking. Only superusers can change this setting.
</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> SQL-language functions that are simple enough to be <SPAN
CLASS="QUOTE"
>"inlined"</SPAN
>
into the calling query will not be tracked, regardless of this
setting.
</P
></BLOCKQUOTE
></DIV
></DD
><DT
><A
NAME="GUC-UPDATE-PROCESS-TITLE"
></A
><TT
CLASS="VARNAME"
>update_process_title</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)</DT
><DD
><P
> Enables updating of the process title every time a new SQL command
is received by the server. The process title is typically viewed
by the <TT
CLASS="COMMAND"
>ps</TT
> command,
or in Windows by using the <SPAN
CLASS="APPLICATION"
>Process Explorer</SPAN
>.
Only superusers can change this setting.
</P
></DD
><DT
><A
NAME="GUC-STATS-TEMP-DIRECTORY"
></A
><TT
CLASS="VARNAME"
>stats_temp_directory</TT
> (<TT
CLASS="TYPE"
>string</TT
>)</DT
><DD
><P
> Sets the directory to store temporary statistics data in. This can be
a path relative to the data directory or an absolute path. The default
is <TT
CLASS="FILENAME"
>pg_stat_tmp</TT
>. Pointing this at a RAM-based
file system will decrease physical I/O requirements and can lead to
improved performance.
This parameter can only be set in the <TT
CLASS="FILENAME"
>postgresql.conf</TT
>
file or on the server command line.
</P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-STATISTICS-MONITOR"
>18.9.2. Statistics Monitoring</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="VARNAME"
>log_statement_stats</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)<BR><TT
CLASS="VARNAME"
>log_parser_stats</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)<BR><TT
CLASS="VARNAME"
>log_planner_stats</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)<BR><TT
CLASS="VARNAME"
>log_executor_stats</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)</DT
><DD
><P
> For each query, output performance statistics of the respective
module to the server log. This is a crude profiling
instrument, similar to the Unix <CODE
CLASS="FUNCTION"
>getrusage()</CODE
> operating
system facility. <TT
CLASS="VARNAME"
>log_statement_stats</TT
> reports total
statement statistics, while the others report per-module statistics.
<TT
CLASS="VARNAME"
>log_statement_stats</TT
> cannot be enabled together with
any of the per-module options. All of these options are disabled by
default. Only superusers can change these settings.
</P
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