diff --git a/doc/src/sgml/ref/create_domain.sgml b/doc/src/sgml/ref/create_domain.sgml
index ce555203486..c111285a69c 100644
--- a/doc/src/sgml/ref/create_domain.sgml
+++ b/doc/src/sgml/ref/create_domain.sgml
@@ -283,7 +283,8 @@ CREATE TABLE us_snail_addy (
   <para>
    The syntax <literal>NOT NULL</literal> in this command is a
    <productname>PostgreSQL</productname> extension.  (A standard-conforming
-   way to write the same would be <literal>CHECK (VALUE IS NOT
+   way to write the same for non-composite data types would be
+   <literal>CHECK (VALUE IS NOT
    NULL)</literal>.  However, per <xref linkend="sql-createdomain-notes"/>,
    such constraints are best avoided in practice anyway.)  The
    <literal>NULL</literal> <quote>constraint</quote> is a
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 1d1aa27d450..01804b085b3 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -3109,6 +3109,13 @@ restriction_is_always_true(PlannerInfo *root,
 		if (nulltest->nulltesttype != IS_NOT_NULL)
 			return false;
 
+		/*
+		 * Empty rows can appear NULL in some contexts and NOT NULL in others,
+		 * so avoid this optimization for row expressions.
+		 */
+		if (nulltest->argisrow)
+			return false;
+
 		return expr_is_nonnullable(root, nulltest->arg);
 	}
 
@@ -3167,6 +3174,13 @@ restriction_is_always_false(PlannerInfo *root,
 		if (nulltest->nulltesttype != IS_NULL)
 			return false;
 
+		/*
+		 * Empty rows can appear NULL in some contexts and NOT NULL in others,
+		 * so avoid this optimization for row expressions.
+		 */
+		if (nulltest->argisrow)
+			return false;
+
 		return expr_is_nonnullable(root, nulltest->arg);
 	}