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diff --git a/doc/src/sgml/html/runtime-config-autovacuum.html b/doc/src/sgml/html/runtime-config-autovacuum.html new file mode 100644 index 0000000..91718f9 --- /dev/null +++ b/doc/src/sgml/html/runtime-config-autovacuum.html @@ -0,0 +1,163 @@ +<?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>20.10. Automatic Vacuuming</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-statistics.html" title="20.9. Run-time Statistics" /><link rel="next" href="runtime-config-client.html" title="20.11. Client Connection Defaults" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">20.10. Automatic Vacuuming</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="runtime-config-statistics.html" title="20.9. Run-time Statistics">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-client.html" title="20.11. Client Connection Defaults">Next</a></td></tr></table><hr /></div><div class="sect1" id="RUNTIME-CONFIG-AUTOVACUUM"><div class="titlepage"><div><div><h2 class="title" style="clear: both">20.10. Automatic Vacuuming</h2></div></div></div><a id="id-1.6.7.13.2" class="indexterm"></a><p> + These settings control the behavior of the <em class="firstterm">autovacuum</em> + feature. Refer to <a class="xref" href="routine-vacuuming.html#AUTOVACUUM" title="25.1.6. The Autovacuum Daemon">Section 25.1.6</a> for more information. + Note that many of these settings can be overridden on a per-table + basis; see <a class="xref" href="sql-createtable.html#SQL-CREATETABLE-STORAGE-PARAMETERS" title="Storage Parameters">Storage Parameters</a>. + </p><div class="variablelist"><dl class="variablelist"><dt id="GUC-AUTOVACUUM"><span class="term"><code class="varname">autovacuum</code> (<code class="type">boolean</code>) + <a id="id-1.6.7.13.4.1.1.3" class="indexterm"></a> + </span></dt><dd><p> + Controls whether the server should run the + autovacuum launcher daemon. This is on by default; however, + <a class="xref" href="runtime-config-statistics.html#GUC-TRACK-COUNTS">track_counts</a> must also be enabled for + autovacuum to work. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; however, autovacuuming can be + disabled for individual tables by changing table storage parameters. + </p><p> + Note that even when this parameter is disabled, the system + will launch autovacuum processes if necessary to + prevent transaction ID wraparound. See <a class="xref" href="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND" title="25.1.5. Preventing Transaction ID Wraparound Failures">Section 25.1.5</a> for more information. + </p></dd><dt id="GUC-AUTOVACUUM-MAX-WORKERS"><span class="term"><code class="varname">autovacuum_max_workers</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.2.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the maximum number of autovacuum processes (other than the + autovacuum launcher) that may be running at any one time. The default + is three. This parameter can only be set at server start. + </p></dd><dt id="GUC-AUTOVACUUM-NAPTIME"><span class="term"><code class="varname">autovacuum_naptime</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.3.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the minimum delay between autovacuum runs on any given + database. In each round the daemon examines the + database and issues <code class="command">VACUUM</code> and <code class="command">ANALYZE</code> commands + as needed for tables in that database. + If this value is specified without units, it is taken as seconds. + The default is one minute (<code class="literal">1min</code>). + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-THRESHOLD"><span class="term"><code class="varname">autovacuum_vacuum_threshold</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.4.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the minimum number of updated or deleted tuples needed + to trigger a <code class="command">VACUUM</code> in any one table. + The default is 50 tuples. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-INSERT-THRESHOLD"><span class="term"><code class="varname">autovacuum_vacuum_insert_threshold</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.5.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the number of inserted tuples needed to trigger a + <code class="command">VACUUM</code> in any one table. + The default is 1000 tuples. If -1 is specified, autovacuum will not + trigger a <code class="command">VACUUM</code> operation on any tables based on + the number of inserts. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-ANALYZE-THRESHOLD"><span class="term"><code class="varname">autovacuum_analyze_threshold</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.6.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the minimum number of inserted, updated or deleted tuples + needed to trigger an <code class="command">ANALYZE</code> in any one table. + The default is 50 tuples. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-SCALE-FACTOR"><span class="term"><code class="varname">autovacuum_vacuum_scale_factor</code> (<code class="type">floating point</code>) + <a id="id-1.6.7.13.4.7.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies a fraction of the table size to add to + <code class="varname">autovacuum_vacuum_threshold</code> + when deciding whether to trigger a <code class="command">VACUUM</code>. + The default is 0.2 (20% of table size). + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-INSERT-SCALE-FACTOR"><span class="term"><code class="varname">autovacuum_vacuum_insert_scale_factor</code> (<code class="type">floating point</code>) + <a id="id-1.6.7.13.4.8.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies a fraction of the table size to add to + <code class="varname">autovacuum_vacuum_insert_threshold</code> + when deciding whether to trigger a <code class="command">VACUUM</code>. + The default is 0.2 (20% of table size). + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-ANALYZE-SCALE-FACTOR"><span class="term"><code class="varname">autovacuum_analyze_scale_factor</code> (<code class="type">floating point</code>) + <a id="id-1.6.7.13.4.9.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies a fraction of the table size to add to + <code class="varname">autovacuum_analyze_threshold</code> + when deciding whether to trigger an <code class="command">ANALYZE</code>. + The default is 0.1 (10% of table size). + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-FREEZE-MAX-AGE"><span class="term"><code class="varname">autovacuum_freeze_max_age</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.10.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the maximum age (in transactions) that a table's + <code class="structname">pg_class</code>.<code class="structfield">relfrozenxid</code> field can + attain before a <code class="command">VACUUM</code> operation is forced + to prevent transaction ID wraparound within the table. + Note that the system will launch autovacuum processes to + prevent wraparound even when autovacuum is otherwise disabled. + </p><p> + Vacuum also allows removal of old files from the + <code class="filename">pg_xact</code> subdirectory, which is why the default + is a relatively low 200 million transactions. + This parameter can only be set at server start, but the setting + can be reduced for individual tables by + changing table storage parameters. + For more information see <a class="xref" href="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND" title="25.1.5. Preventing Transaction ID Wraparound Failures">Section 25.1.5</a>. + </p></dd><dt id="GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE"><span class="term"><code class="varname">autovacuum_multixact_freeze_max_age</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.11.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the maximum age (in multixacts) that a table's + <code class="structname">pg_class</code>.<code class="structfield">relminmxid</code> field can + attain before a <code class="command">VACUUM</code> operation is forced to + prevent multixact ID wraparound within the table. + Note that the system will launch autovacuum processes to + prevent wraparound even when autovacuum is otherwise disabled. + </p><p> + Vacuuming multixacts also allows removal of old files from the + <code class="filename">pg_multixact/members</code> and <code class="filename">pg_multixact/offsets</code> + subdirectories, which is why the default is a relatively low + 400 million multixacts. + This parameter can only be set at server start, but the setting can + be reduced for individual tables by changing table storage parameters. + For more information see <a class="xref" href="routine-vacuuming.html#VACUUM-FOR-MULTIXACT-WRAPAROUND" title="25.1.5.1. Multixacts and Wraparound">Section 25.1.5.1</a>. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-COST-DELAY"><span class="term"><code class="varname">autovacuum_vacuum_cost_delay</code> (<code class="type">floating point</code>) + <a id="id-1.6.7.13.4.12.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the cost delay value that will be used in automatic + <code class="command">VACUUM</code> operations. If -1 is specified, the regular + <a class="xref" href="runtime-config-resource.html#GUC-VACUUM-COST-DELAY">vacuum_cost_delay</a> value will be used. + If this value is specified without units, it is taken as milliseconds. + The default value is 2 milliseconds. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd><dt id="GUC-AUTOVACUUM-VACUUM-COST-LIMIT"><span class="term"><code class="varname">autovacuum_vacuum_cost_limit</code> (<code class="type">integer</code>) + <a id="id-1.6.7.13.4.13.1.3" class="indexterm"></a> + </span></dt><dd><p> + Specifies the cost limit value that will be used in automatic + <code class="command">VACUUM</code> operations. If -1 is specified (which is the + default), the regular + <a class="xref" href="runtime-config-resource.html#GUC-VACUUM-COST-LIMIT">vacuum_cost_limit</a> value will be used. Note that + the value is distributed proportionally among the running autovacuum + workers, if there is more than one, so that the sum of the limits for + each worker does not exceed the value of this variable. + This parameter can only be set in the <code class="filename">postgresql.conf</code> + file or on the server command line; + but the setting can be overridden for individual tables by + changing table storage parameters. + </p></dd></dl></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="runtime-config-statistics.html" title="20.9. Run-time Statistics">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime-config.html" title="Chapter 20. 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