diff --git a/doc/src/sgml/parallel.sgml b/doc/src/sgml/parallel.sgml
index dd7834a763..ea941e4fb4 100644
--- a/doc/src/sgml/parallel.sgml
+++ b/doc/src/sgml/parallel.sgml
@@ -423,7 +423,9 @@ EXPLAIN SELECT * FROM pgbench_accounts WHERE filler LIKE '%x%';
     VERBOSE)</literal> to display per-worker statistics for each plan node.
     This may be useful in determining whether the work is being evenly
     distributed between all plan nodes and more generally in understanding the
-    performance characteristics of the plan.
+    performance characteristics of the plan. Note, that the parallel nodes
+    may report zero rows returned due internal calculations when one or more
+    rows are actually being returned.
   </para>

  </sect2>