diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 7e20a8a796..40159b8dcd 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -950,7 +950,7 @@ ERROR:  could not serialize access due to read/write dependencies among transact
         <para>
          Acquired by <command>VACUUM</command> (without <option>FULL</option>),
          <command>ANALYZE</command>, <command>CREATE INDEX CONCURRENTLY</command>,
-         <command>CREATE STATISTICS</command> and
+         <command>CREATE STATISTICS</command>, <command>COMMENT ON</command> and
          <command>ALTER TABLE VALIDATE</command> and other
          <command>ALTER TABLE</command> variants (for full details see
          <xref linkend="sql-altertable"/>).
diff --git a/doc/src/sgml/ref/comment.sgml b/doc/src/sgml/ref/comment.sgml
index fd7492a255..138cf718ce 100644
--- a/doc/src/sgml/ref/comment.sgml
+++ b/doc/src/sgml/ref/comment.sgml
@@ -90,6 +90,11 @@ COMMENT ON
    Comments are automatically dropped when their object is dropped.
   </para>
 
+  <para>
+   A <literal>SHARE UPDATE EXCLUSIVE</literal> lock is acquired on the
+   object to be commented.
+  </para>
+
   <para>
    For most kinds of object, only the object's owner can set the comment.
    Roles don't have owners, so the rule for <literal>COMMENT ON ROLE</literal> is