diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index c7f7feaaf89..2e04b8784d9 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -608,8 +608,9 @@
       <varname>pg_stat_statements.track_planning</varname> controls whether
       planning operations and duration are tracked by the module.
       Enabling this parameter may incur a noticeable performance penalty,
-      especially when a fewer kinds of queries are executed on many
-      concurrent connections.
+      especially when statements with identical query structure are executed
+      by many concurrent connections which compete to update a small number of
+      <structname>pg_stat_statements</structname> entries.
       The default value is <literal>off</literal>.
       Only superusers can change this setting.
      </para>