From 923f6f3d758edb1f64eadef1f5bb1dfb873f4b21 Mon Sep 17 00:00:00 2001
From: Daniil Davidov <d.davydov@postgrespro.ru>
Date: Tue, 17 Mar 2026 03:23:38 +0700
Subject: [PATCH v27 5/5] Documentation for parallel autovacuum

---
 doc/src/sgml/config.sgml           | 18 ++++++++++++++++++
 doc/src/sgml/maintenance.sgml      | 12 ++++++++++++
 doc/src/sgml/ref/create_table.sgml | 20 ++++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8cdd826fbd3..7741796c6b0 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2918,6 +2918,7 @@ include_dir 'conf.d'
         <para>
          When changing this value, consider also adjusting
          <xref linkend="guc-max-parallel-workers"/>,
+         <xref linkend="guc-autovacuum-max-parallel-workers"/>,
          <xref linkend="guc-max-parallel-maintenance-workers"/>, and
          <xref linkend="guc-max-parallel-workers-per-gather"/>.
         </para>
@@ -9395,6 +9396,23 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
        </listitem>
       </varlistentry>
 
+      <varlistentry id="guc-autovacuum-max-parallel-workers" xreflabel="autovacuum_max_parallel_workers">
+        <term><varname>autovacuum_max_parallel_workers</varname> (<type>integer</type>)
+        <indexterm>
+         <primary><varname>autovacuum_max_parallel_workers</varname></primary>
+         <secondary>configuration parameter</secondary>
+        </indexterm>
+        </term>
+        <listitem>
+         <para>
+          Sets the maximum number of parallel autovacuum workers that
+          can be used for parallel index vacuuming at one time by a single
+          autovacuum worker. Is capped by <xref linkend="guc-max-parallel-workers"/>.
+          The default is 2.
+         </para>
+        </listitem>
+     </varlistentry>
+
      </variablelist>
     </sect2>
 
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 7c958b06273..f2a280db569 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -926,6 +926,18 @@ HINT:  Execute a database-wide VACUUM in that database.
     autovacuum workers' activity.
    </para>
 
+   <para>
+    If an autovacuum worker process comes across a table with the enabled
+    <xref linkend="reloption-autovacuum-parallel-workers"/> storage parameter,
+    it will launch parallel workers in order to vacuum indexes of this table
+    in a parallel mode. Parallel workers are taken from the pool of processes
+    established by <xref linkend="guc-max-worker-processes"/>, limited by
+    <xref linkend="guc-max-parallel-workers"/>.
+    The number of parallel workers that can be taken from pool by a single
+    autovacuum worker is limited by the <xref linkend="guc-autovacuum-max-parallel-workers"/>
+    configuration parameter.
+   </para>
+
    <para>
     If several large tables all become eligible for vacuuming in a short
     amount of time, all autovacuum workers might become occupied with
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 982532fe725..4894de021cd 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1718,6 +1718,26 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+  <varlistentry id="reloption-autovacuum-parallel-workers" xreflabel="autovacuum_parallel_workers">
+    <term><literal>autovacuum_parallel_workers</literal> (<type>integer</type>)
+    <indexterm>
+     <primary><varname>autovacuum_parallel_workers</varname> storage parameter</primary>
+    </indexterm>
+    </term>
+    <listitem>
+     <para>
+      Sets the maximum number of parallel autovacuum workers that can process
+      indexes of this table.
+      The default value is -1, which means no parallel index vacuuming for
+      this table. If value is 0 then parallel degree will computed based on
+      number of indexes.
+      Note that the computed number of workers may not actually be available at
+      run time. If this occurs, the autovacuum will run with fewer workers
+      than expected.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry id="reloption-autovacuum-vacuum-threshold" xreflabel="autovacuum_vacuum_threshold">
     <term><literal>autovacuum_vacuum_threshold</literal>, <literal>toast.autovacuum_vacuum_threshold</literal> (<type>integer</type>)
     <indexterm>
-- 
2.43.0