diff --git a/doc/src/sgml/pgprewarm.sgml b/doc/src/sgml/pgprewarm.sgml
index 75f45b91b67..6907f214eb8 100644
--- a/doc/src/sgml/pgprewarm.sgml
+++ b/doc/src/sgml/pgprewarm.sgml
@@ -35,8 +35,10 @@ pg_prewarm(regclass, mode text default 'buffer', fork text default 'main',
    The fourth argument is the first block number to prewarm
    (<literal>NULL</literal> is accepted as a synonym for zero).  The fifth
    argument is the last block number to prewarm (<literal>NULL</literal>
-   means prewarm through the last block in the relation).  The return value
-   is the number of blocks prewarmed.
+   means prewarm through the last block in the relation).  The block
+   range allows a single relation to be loaded in parallel using multiple
+   concurent function calls.  The return value is the number of blocks
+   prewarmed.
   </para>
 
   <para>