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diff --git a/doc/src/sgml/html/runtime-config-statistics.html b/doc/src/sgml/html/runtime-config-statistics.html new file mode 100644 index 0000000..e9f9279 --- /dev/null +++ b/doc/src/sgml/html/runtime-config-statistics.html @@ -0,0 +1,149 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>20.9. Run-time Statistics</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="runtime-config-logging.html" title="20.8. Error Reporting and Logging" /><link rel="next" href="runtime-config-autovacuum.html" title="20.10. Automatic Vacuuming" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">20.9. Run-time Statistics</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="runtime-config-logging.html" title="20.8. Error Reporting and Logging">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime-config.html" title="Chapter 20. Server Configuration">Up</a></td><th width="60%" align="center">Chapter 20. Server Configuration</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="runtime-config-autovacuum.html" title="20.10. Automatic Vacuuming">Next</a></td></tr></table><hr /></div><div class="sect1" id="RUNTIME-CONFIG-STATISTICS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">20.9. Run-time Statistics</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="runtime-config-statistics.html#RUNTIME-CONFIG-CUMULATIVE-STATISTICS">20.9.1. Cumulative Query and Index Statistics</a></span></dt><dt><span class="sect2"><a href="runtime-config-statistics.html#RUNTIME-CONFIG-STATISTICS-MONITOR">20.9.2. Statistics Monitoring</a></span></dt></dl></div><div class="sect2" id="RUNTIME-CONFIG-CUMULATIVE-STATISTICS"><div class="titlepage"><div><div><h3 class="title">20.9.1. Cumulative Query and Index Statistics</h3></div></div></div><p> + These parameters control the server-wide cumulative statistics system. + When enabled, the data that is collected can be accessed via the + <code class="structname">pg_stat</code> and <code class="structname">pg_statio</code> + family of system views. Refer to <a class="xref" href="monitoring.html" title="Chapter 28. Monitoring Database Activity">Chapter 28</a> for more + information. + </p><div class="variablelist"><dl class="variablelist"><dt id="GUC-TRACK-ACTIVITIES"><span class="term"><code class="varname">track_activities</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.2.3.1.1.3" class="indexterm"></a> + </span></dt><dd><p> + Enables the collection of information on the currently + executing command of each session, along with its identifier and the + time when that command began execution. This parameter is on by + default. Note that even when enabled, this information is only + visible to superusers, roles with privileges of the + <code class="literal">pg_read_all_stats</code> role and the user owning the + sessions being reported on (including sessions belonging to a role they + have the privileges of), so it should not represent a security risk. + Only superusers and users with the appropriate <code class="literal">SET</code> + privilege can change this setting. + </p></dd><dt id="GUC-TRACK-ACTIVITY-QUERY-SIZE"><span class="term"><code class="varname">track_activity_query_size</code> (<code class="type">integer</code>) + <a id="id-1.6.7.12.2.3.2.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the amount of memory reserved to store the text of the + currently executing command for each active session, for the + <code class="structname">pg_stat_activity</code>.<code class="structfield">query</code> field. + If this value is specified without units, it is taken as bytes. + The default value is 1024 bytes. + This parameter can only be set at server start. + </p></dd><dt id="GUC-TRACK-COUNTS"><span class="term"><code class="varname">track_counts</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.2.3.3.1.3" class="indexterm"></a> + </span></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 and users with the appropriate <code class="literal">SET</code> + privilege can change this setting. + </p></dd><dt id="GUC-TRACK-IO-TIMING"><span class="term"><code class="varname">track_io_timing</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.2.3.4.1.3" class="indexterm"></a> + </span></dt><dd><p> + Enables timing of database I/O calls. This parameter is off by + default, as it will repeatedly query the operating system for + the current time, which may cause significant overhead on some + platforms. You can use the <a class="xref" href="pgtesttiming.html" title="pg_test_timing"><span class="refentrytitle"><span class="application">pg_test_timing</span></span></a> tool to + measure the overhead of timing on your system. + I/O timing information is + displayed in <a class="link" href="monitoring-stats.html#MONITORING-PG-STAT-DATABASE-VIEW" title="28.2.15. pg_stat_database"> + <code class="structname">pg_stat_database</code></a>, in the output of + <a class="xref" href="sql-explain.html" title="EXPLAIN"><span class="refentrytitle">EXPLAIN</span></a> when the <code class="literal">BUFFERS</code> option + is used, in the output of <a class="xref" href="sql-vacuum.html" title="VACUUM"><span class="refentrytitle">VACUUM</span></a> when + the <code class="literal">VERBOSE</code> option is used, by autovacuum + for auto-vacuums and auto-analyzes, when <a class="xref" href="runtime-config-logging.html#GUC-LOG-AUTOVACUUM-MIN-DURATION">log_autovacuum_min_duration</a> is set and by + <a class="xref" href="pgstatstatements.html" title="F.32. pg_stat_statements">pg_stat_statements</a>. + Only superusers and users with the appropriate <code class="literal">SET</code> + privilege can change this setting. + </p></dd><dt id="GUC-TRACK-WAL-IO-TIMING"><span class="term"><code class="varname">track_wal_io_timing</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.2.3.5.1.3" class="indexterm"></a> + </span></dt><dd><p> + Enables timing of WAL I/O calls. This parameter is off by default, + as it will repeatedly query the operating system for the current time, + which may cause significant overhead on some platforms. + You can use the <span class="application">pg_test_timing</span> tool to + measure the overhead of timing on your system. + I/O timing information is + displayed in <a class="link" href="monitoring-stats.html#MONITORING-PG-STAT-WAL-VIEW" title="28.2.14. pg_stat_wal"> + <code class="structname">pg_stat_wal</code></a>. + Only superusers and users with the appropriate <code class="literal">SET</code> + privilege can change this setting. + </p></dd><dt id="GUC-TRACK-FUNCTIONS"><span class="term"><code class="varname">track_functions</code> (<code class="type">enum</code>) + <a id="id-1.6.7.12.2.3.6.1.3" class="indexterm"></a> + </span></dt><dd><p> + Enables tracking of function call counts and time used. Specify + <code class="literal">pl</code> to track only procedural-language functions, + <code class="literal">all</code> to also track SQL and C language functions. + The default is <code class="literal">none</code>, which disables function + statistics tracking. + Only superusers and users with the appropriate <code class="literal">SET</code> + privilege can change this setting. + </p><div class="note"><h3 class="title">Note</h3><p> + SQL-language functions that are simple enough to be <span class="quote">“<span class="quote">inlined</span>”</span> + into the calling query will not be tracked, regardless of this + setting. + </p></div></dd><dt id="GUC-STATS-FETCH-CONSISTENCY"><span class="term"><code class="varname">stats_fetch_consistency</code> (<code class="type">enum</code>) + <a id="id-1.6.7.12.2.3.7.1.3" class="indexterm"></a> + </span></dt><dd><p> + Determines the behavior when cumulative statistics are accessed + multiple times within a transaction. When set to + <code class="literal">none</code>, each access re-fetches counters from shared + memory. When set to <code class="literal">cache</code>, the first access to + statistics for an object caches those statistics until the end of the + transaction unless <code class="function">pg_stat_clear_snapshot()</code> is + called. When set to <code class="literal">snapshot</code>, the first statistics + access caches all statistics accessible in the current database, until + the end of the transaction unless + <code class="function">pg_stat_clear_snapshot()</code> is called. Changing this + parameter in a transaction discards the statistics snapshot. + The default is <code class="literal">cache</code>. + </p><div class="note"><h3 class="title">Note</h3><p> + <code class="literal">none</code> is most suitable for monitoring systems. If + values are only accessed once, it is the most + efficient. <code class="literal">cache</code> ensures repeat accesses yield the + same values, which is important for queries involving + e.g. self-joins. <code class="literal">snapshot</code> can be useful when + interactively inspecting statistics, but has higher overhead, + particularly if many database objects exist. + </p></div></dd></dl></div></div><div class="sect2" id="RUNTIME-CONFIG-STATISTICS-MONITOR"><div class="titlepage"><div><div><h3 class="title">20.9.2. Statistics Monitoring</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt id="GUC-COMPUTE-QUERY-ID"><span class="term"><code class="varname">compute_query_id</code> (<code class="type">enum</code>) + <a id="id-1.6.7.12.3.2.1.1.3" class="indexterm"></a> + </span></dt><dd><p> + Enables in-core computation of a query identifier. + Query identifiers can be displayed in the <a class="link" href="monitoring-stats.html#MONITORING-PG-STAT-ACTIVITY-VIEW" title="28.2.3. pg_stat_activity"><code class="structname">pg_stat_activity</code></a> + view, using <code class="command">EXPLAIN</code>, or emitted in the log if + configured via the <a class="xref" href="runtime-config-logging.html#GUC-LOG-LINE-PREFIX">log_line_prefix</a> parameter. + The <a class="xref" href="pgstatstatements.html" title="F.32. pg_stat_statements">pg_stat_statements</a> extension also requires a query + identifier to be computed. Note that an external module can + alternatively be used if the in-core query identifier computation + method is not acceptable. In this case, in-core computation + must be always disabled. + Valid values are <code class="literal">off</code> (always disabled), + <code class="literal">on</code> (always enabled), <code class="literal">auto</code>, + which lets modules such as <a class="xref" href="pgstatstatements.html" title="F.32. pg_stat_statements">pg_stat_statements</a> + automatically enable it, and <code class="literal">regress</code> which + has the same effect as <code class="literal">auto</code>, except that the + query identifier is not shown in the <code class="literal">EXPLAIN</code> output + in order to facilitate automated regression testing. + The default is <code class="literal">auto</code>. + </p><div class="note"><h3 class="title">Note</h3><p> + To ensure that only one query identifier is calculated and + displayed, extensions that calculate query identifiers should + throw an error if a query identifier has already been computed. + </p></div></dd><dt><span class="term"><code class="varname">log_statement_stats</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.3.2.2.1.3" class="indexterm"></a> + <br /></span><span class="term"><code class="varname">log_parser_stats</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.3.2.2.2.3" class="indexterm"></a> + <br /></span><span class="term"><code class="varname">log_planner_stats</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.3.2.2.3.3" class="indexterm"></a> + <br /></span><span class="term"><code class="varname">log_executor_stats</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.12.3.2.2.4.3" class="indexterm"></a> + </span></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. <code class="varname">log_statement_stats</code> reports total + statement statistics, while the others report per-module statistics. + <code class="varname">log_statement_stats</code> cannot be enabled together with + any of the per-module options. All of these options are disabled by + default. + Only superusers and users with the appropriate <code class="literal">SET</code> + privilege can change these settings. + </p></dd></dl></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="runtime-config-logging.html" title="20.8. Error Reporting and Logging">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime-config.html" title="Chapter 20. 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