3 files changed, 39 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/alter_index.sgml b/doc/src/sgml/ref/alter_index.sgml
index 793119d2fc1..214005a86c5 100644
--- a/doc/src/sgml/ref/alter_index.sgml
+++ b/doc/src/sgml/ref/alter_index.sgml
@@ -25,6 +25,7 @@ ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RENA
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET TABLESPACE <replaceable class="parameter">tablespace_name</replaceable>
 ALTER INDEX <replaceable class="parameter">name</replaceable> ATTACH PARTITION <replaceable class="parameter">index_name</replaceable>
 ALTER INDEX <replaceable class="parameter">name</replaceable> DEPENDS ON EXTENSION <replaceable class="parameter">extension_name</replaceable>
+ALTER INDEX <replaceable class="parameter">name</replaceable> ALTER COLLATION <replaceable class="parameter">collation_name</replaceable> REFRESH VERSION
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RESET ( <replaceable class="parameter">storage_parameter</replaceable> [, ... ] )
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="parameter">column_number</replaceable>
@@ -113,6 +114,20 @@ ALTER INDEX ALL IN TABLESPACE <replaceable class="parameter">name</replaceable>
    </varlistentry>
 
    <varlistentry>
+    <term><literal>ALTER COLLATION <replaceable class="parameter">collation_name</replaceable> REFRESH VERSION</literal></term>
+    <listitem>
+     <para>
+      Silences warnings about mismatched collation versions, by declaring
+      that the index is compatible with the current collation definition.
+      Be aware that incorrect use of this command can hide index corruption.
+      If you don't know whether a collation's definition has changed
+      incompatibly, <xref linkend="sql-reindex"/> is a safe alternative.
+      See <xref linkend="collation-versions"/> for more information.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><literal>SET ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
     <listitem>
      <para>
diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index b59c5697a36..92e1d09a55c 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -216,6 +216,21 @@ PostgreSQL documentation
      </varlistentry>
 
      <varlistentry>
+      <term><option>--index-collation-versions-unknown</option></term>
+      <listitem>
+       <para>
+        When upgrading indexes from releases before 14 that didn't track
+        collation versions, <application>pg_upgrade</application>
+        assumes by default that the upgraded indexes are compatible with the
+        currently installed versions of relevant collations (see
+        <xref linkend="collation-versions"/>).  Specify
+        <option>--index-collation-versions-unknown</option> to mark
+        them as needing to be rebuilt instead.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><option>-?</option></term>
       <term><option>--help</option></term>
       <listitem><para>show help, then exit</para></listitem>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index fa43e3a9720..f6d425a6910 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -40,6 +40,15 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
    <itemizedlist>
     <listitem>
      <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause index scans to fail to
+      find keys that are present.  See <xref linkend="collation-versions"/> for
+      more information.
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
       practice indexes can become corrupted due to software bugs or