diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d97d77ea227..7faa1978550 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6808,7 +6808,7 @@ local0.*    /var/log/postgresql
 
        <note>
         <para>
-          The logging collector is designed to never lose messages.  This means
+          The logging collector is designed to avoid dropping messages.  This means
           that in case of extremely high load, server processes could be
           blocked while trying to send additional log messages when the
           collector has fallen behind.  In contrast, <application>syslog</application>
@@ -6816,6 +6816,11 @@ local0.*    /var/log/postgresql
           may fail to log some messages in such cases but it will not block
           the rest of the system.
         </para>
+        <para>
+         The logging collector does not guarantee that log messages have
+         reached durable storage.  It can still lose messages due to a system
+         crash, power loss, or an error while writing the log file.
+        </para>
        </note>
 
       </listitem>