diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 2a2c161695..4ec61d4833 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -6329,7 +6329,7 @@ NotNullImpliedByRelConstraints(Relation rel, Form_pg_attribute attr)
 
 	if (ConstraintImpliedByRelConstraint(rel, list_make1(nnulltest), NIL))
 	{
-		ereport(DEBUG1,
+		ereport(NOTICE,
 				(errmsg("existing constraints on column \"%s\".\"%s\" are sufficient to prove that it does not contain nulls",
 						RelationGetRelationName(rel), NameStr(attr->attname))));
 		return true;
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 95d5bee029..fb8b3583f1 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1089,12 +1089,14 @@ alter table atacc1 drop constraint atacc1_constr_invalid;
 update atacc1 set test_a = 1;
 alter table atacc1 add constraint atacc1_constr_a_valid check(test_a is not null);
 alter table atacc1 alter test_a set not null;
+NOTICE:  existing constraints on column "atacc1"."test_a" are sufficient to prove that it does not contain nulls
 delete from atacc1;
 insert into atacc1 values (2, null);
 alter table atacc1 alter test_a drop not null;
 -- test multiple set not null at same time
 -- test_a checked by atacc1_constr_a_valid, test_b should fail by table scan
 alter table atacc1 alter test_a set not null, alter test_b set not null;
+NOTICE:  existing constraints on column "atacc1"."test_a" are sufficient to prove that it does not contain nulls
 ERROR:  column "test_b" contains null values
 -- commands order has no importance
 alter table atacc1 alter test_b set not null, alter test_a set not null;
@@ -1106,6 +1108,8 @@ alter table atacc1 alter test_a drop not null, alter test_b drop not null;
 -- both column has check constraints
 alter table atacc1 add constraint atacc1_constr_b_valid check(test_b is not null);
 alter table atacc1 alter test_b set not null, alter test_a set not null;
+NOTICE:  existing constraints on column "atacc1"."test_b" are sufficient to prove that it does not contain nulls
+NOTICE:  existing constraints on column "atacc1"."test_a" are sufficient to prove that it does not contain nulls
 drop table atacc1;
 -- test inheritance
 create table parent (a int);