diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 49547ee..8803709 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6052,14 +6052,16 @@ SET XML OPTION { DOCUMENT | CONTENT };
       <listitem>
        <para>
         This variable specifies one or more shared libraries that are to be
-        preloaded at connection start.  This parameter cannot be changed after
-        the start of a particular session.  If a specified library is not
+        preloaded at connection start.  This option is effective only when it
+        is set at session start via <command>ALTER USER ... SET</> command (or
+        postgresq.conf) so changing this variable after the start of a
+        particular session has no effect.  If a specified library is not
         found, the connection attempt will fail.
        </para>
 
        <para>
-        This option can be set by any user.  Because of that, the libraries
-        that can be loaded are restricted to those appearing in the
+        Since non-supersers are allowed to set it, the libraries that can be
+        loaded are restricted to those appearing in the
         <filename>plugins</> subdirectory of the installation's
         standard library directory.  (It is the database administrator's
         responsibility to ensure that only <quote>safe</> libraries
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a8a17c2..f128f32 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2895,7 +2895,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"local_preload_libraries", PGC_BACKEND, CLIENT_CONN_PRELOAD,
+		{"local_preload_libraries", PGC_USERSET, CLIENT_CONN_PRELOAD,
 			gettext_noop("Lists unprivileged shared libraries to preload into each backend."),
 			NULL,
 			GUC_LIST_INPUT | GUC_LIST_QUOTE