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Integrate autovacuum functionality into the backend. There's still a
few loose ends to be dealt with, but it seems to work. Alvaro Herrera, based on the contrib code by Matthew O'Connor.
This commit is contained in:
Tom Lane
@ -1,6 +1,6 @@
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<!--
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Documentation of the system catalogs, directed toward PostgreSQL developers
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$PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.107 2005/07/07 20:39:56 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.108 2005/07/14 05:13:38 tgl Exp $
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-->
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<chapter id="catalogs">
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@ -88,6 +88,11 @@
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<entry>authorization identifier membership relationships</entry>
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</row>
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<row>
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<entry><link linkend="catalog-pg-autovacuum"><structname>pg_autovacuum</structname></link></entry>
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<entry>per-relation autovacuum configuration parameters</entry>
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</row>
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<row>
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<entry><link linkend="catalog-pg-cast"><structname>pg_cast</structname></link></entry>
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<entry>casts (data type conversions)</entry>
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@ -1102,6 +1107,104 @@
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</sect1>
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<sect1 id="catalog-pg-autovacuum">
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<title><structname>pg_autovacuum</structname></title>
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<indexterm zone="catalog-pg-autovacuum">
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<primary>pg_autovacuum</primary>
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</indexterm>
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<para>
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The catalog <structname>pg_autovacuum</structname> stores optional
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per-relation configuration parameters for <quote>autovacuum</>.
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If there is an entry here for a particular relation, the given
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parameters will be used for autovacuuming that table. If no entry
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is present, the system-wide defaults will be used.
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</para>
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<table>
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<title><structname>pg_autovacuum</> Columns</title>
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<tgroup cols=4>
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<thead>
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<row>
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<entry>Name</entry>
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<entry>Type</entry>
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<entry>References</entry>
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<entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><structfield>vacrelid</structfield></entry>
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<entry><type>oid</type></entry>
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<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
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<entry>The table this entry is for</entry>
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</row>
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<row>
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<entry><structfield>enabled</structfield></entry>
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<entry><type>bool</type></entry>
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<entry></entry>
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<entry>If false, this table is never autovacuumed</entry>
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</row>
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<row>
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<entry><structfield>vac_base_thresh</structfield></entry>
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<entry><type>integer</type></entry>
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<entry></entry>
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<entry>Minimum number of modified tuples before vacuum</entry>
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</row>
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<row>
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<entry><structfield>vac_scale_factor</structfield></entry>
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<entry><type>float4</type></entry>
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<entry></entry>
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<entry>Multiplier for reltuples to add to
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<structfield>vac_base_thresh</></entry>
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</row>
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<row>
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<entry><structfield>anl_base_thresh</structfield></entry>
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<entry><type>integer</type></entry>
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<entry></entry>
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<entry>Minimum number of modified tuples before analyze</entry>
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</row>
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<row>
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<entry><structfield>anl_scale_factor</structfield></entry>
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<entry><type>float4</type></entry>
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<entry></entry>
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<entry>Multiplier for reltuples to add to
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<structfield>anl_base_thresh</></entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>
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The autovacuum daemon will initiate a <command>VACUUM</> operation
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on a particular table when the number of updated or deleted tuples
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exceeds <structfield>vac_base_thresh</structfield> plus
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<structfield>vac_scale_factor</structfield> times the number of
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live tuples currently estimated to be in the relation.
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Similarly, it will initiate an <command>ANALYZE</> operation
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when the number of inserted, updated or deleted tuples
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exceeds <structfield>anl_base_thresh</structfield> plus
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<structfield>anl_scale_factor</structfield> times the number of
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live tuples currently estimated to be in the relation.
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</para>
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<para>
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Any of the numerical fields can contain <literal>-1</> (or indeed
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any negative value) to indicate that the system-wide default should
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be used for this particular value.
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</para>
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</sect1>
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<sect1 id="catalog-pg-cast">
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<title><structname>pg_cast</structname></title>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.337 2005/07/06 14:45:12 momjian Exp $
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$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.338 2005/07/14 05:13:38 tgl Exp $
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-->
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<chapter Id="runtime">
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@ -3173,7 +3173,7 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Windows
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If on, collected statistics are zeroed out whenever the server
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is restarted. If off, statistics are accumulated across server
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restarts. The default is <literal>on</>. This option can only
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be set at server start.
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be set at server start.
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</para>
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</listitem>
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</varlistentry>
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@ -3182,6 +3182,127 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Windows
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</sect3>
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</sect2>
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<sect2 id="runtime-config-autovacuum">
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<title>Automatic Vacuuming</title>
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<para>
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Beginning in <productname>PostgreSQL</> 8.1, there is an optional server
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process called the <firstterm>autovacuum daemon</>, whose purpose is
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to automate the issuance of periodic <command>VACUUM</> and
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<command>ANALYZE</> commands. When enabled, the autovacuum daemon
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runs periodically and checks for tables that have had a large number
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of updated or deleted tuples. This check uses the row-level statistics
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collection facility; therefore, the autovacuum daemon cannot be used
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unless <xref linkend="guc-stats-start-collector"> and
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<xref linkend="guc-stats-row-level"> are set TRUE. Also, it's
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important to allow a slot for the autovacuum process when choosing
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the value of <xref linkend="guc-superuser-reserved-connections">.
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</para>
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<variablelist>
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<varlistentry id="guc-autovacuum" xreflabel="autovacuum">
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<term><varname>autovacuum</varname> (<type>boolean</type>)</term>
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<indexterm>
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<primary><varname>autovacuum</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Controls whether the server should start the
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autovacuum subprocess. This is off by default.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-autovacuum-naptime" xreflabel="autovacuum_naptime">
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<term><varname>autovacuum_naptime</varname> (<type>integer</type>)</term>
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<indexterm>
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<primary><varname>autovacuum_naptime</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Specifies the delay between activity rounds for the autovacuum
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subprocess. In each round the subprocess examines one database
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and issues <command>VACUUM</> and <command>ANALYZE</> commands
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as needed for tables in that database. The delay is measured
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in seconds, and the default is 60.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-autovacuum-vacuum-threshold" xreflabel="autovacuum_vacuum_threshold">
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<term><varname>autovacuum_vacuum_threshold</varname> (<type>integer</type>)</term>
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<indexterm>
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<primary><varname>autovacuum_vacuum_threshold</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Specifies the minimum number of updated or deleted tuples needed
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to trigger a <command>VACUUM</> in any one table.
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The default is 1000.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-autovacuum-analyze-threshold" xreflabel="autovacuum_analyze_threshold">
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<term><varname>autovacuum_analyze_threshold</varname> (<type>integer</type>)</term>
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<indexterm>
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<primary><varname>autovacuum_analyze_threshold</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Specifies the minimum number of inserted, updated or deleted tuples
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needed to trigger an <command>ANALYZE</> in any one table.
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The default is 500.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-autovacuum-vacuum-scale-factor" xreflabel="autovacuum_vacuum_scale_factor">
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<term><varname>autovacuum_vacuum_scale_factor</varname> (<type>floating point</type>)</term>
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<indexterm>
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<primary><varname>autovacuum_vacuum_scale_factor</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Specifies a fraction of the table size to add to
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<varname>autovacuum_vacuum_threshold</varname>
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when deciding whether to trigger a <command>VACUUM</>.
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The default is 0.4.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-autovacuum-analyze-scale-factor" xreflabel="autovacuum_analyze_scale_factor">
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<term><varname>autovacuum_analyze_scale_factor</varname> (<type>floating point</type>)</term>
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<indexterm>
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<primary><varname>autovacuum_analyze_scale_factor</> configuration parameter</primary>
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</indexterm>
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<listitem>
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<para>
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Specifies a fraction of the table size to add to
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<varname>autovacuum_analyze_threshold</varname>
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when deciding whether to trigger an <command>ANALYZE</>.
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The default is 0.2.
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This option can only be set at server start or in the
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<filename>postgresql.conf</filename> file.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</sect2>
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<sect2 id="runtime-config-client">
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<title>Client Connection Defaults</title>
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Reference in New Issue
Block a user