diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 25e6751590e..41809f15bf2 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1544,6 +1544,9 @@ include_dir 'conf.d'
         the value of <xref linkend="guc-maintenance-work-mem"> should
         be used instead.  The setting has no effect on the behavior of
         <command>VACUUM</command> when run in other contexts.
+        This parameter can only be set in the
+        <filename>postgresql.conf</filename> file or on the server command
+        line.
        </para>
       </listitem>
      </varlistentry>
@@ -7627,6 +7630,11 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
         useful to disable the restart so that the clusterware can gain
         control and take any actions it deems appropriate.
        </para>
+
+       <para>
+        This parameter can only be set in the <filename>postgresql.conf</filename>
+        file or on the server command line.
+       </para>
       </listitem>
      </varlistentry>