diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 9674a16fb..669fd399e 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -524,6 +524,9 @@ test: vec_sonic_hashjoin_number_prepare
 test: vec_sonic_hashjoin_number_nospill
 #test: hw_pwd_complexity
 
+# test serial function
+test: test_serial
+
 test: timeout
 test: dml
 #test: iud