diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index ec264dbb118..87ebda032ef 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1,5 +1,5 @@
@@ -437,6 +437,13 @@ and table_constraint is:
+
+ If primary key column is updated frequently, it may be wise to
+ add an index to the REFERENCES column so that
+ NO ACTION and CASCADE
+ actions associated with the REFERENCES
+ column can be more efficiently performed.
+
@@ -472,6 +479,8 @@ and table_constraint is:
+
+