From b4f453f6ab71eb72cb3a46a5be18e07e5cc285df Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Fri, 4 Apr 2025 15:17:17 +0300
Subject: [PATCH] docs: Clarify that NULL arg to set_config() means reset to
 default

Author: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Zhang Mingli <zmlpostgres@gmail.com>
Discussion: https://www.postgresql.org/message-id/CAKFQuwY0SK6JdCci1VJX6xsztRXgGeVEY-grkENZx%2B3CZpyPcQ@mail.gmail.com
---
 doc/src/sgml/func.sgml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 9f531e23283..0224f93733d 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -28576,6 +28576,11 @@ acl      | {postgres=arwdDxtm/postgres,foo=r/postgres}
         use <literal>false</literal> instead. This function corresponds to
         the SQL command <xref linkend="sql-set"/>.
        </para>
+       <para>
+        <function>set_config</function> accepts the NULL value for
+        <parameter>new_value</parameter>, but as settings cannot be null, it
+        is interpreted as a request to reset the setting to its default value.
+       </para>
        <para>
         <literal>set_config('log_statement_stats', 'off', false)</literal>
         <returnvalue>off</returnvalue>