diff --git a/pkg/db/v1beta1/mysql/mysql.go b/pkg/db/v1beta1/mysql/mysql.go
index 4c25a188bed..a010db69e50 100644
--- a/pkg/db/v1beta1/mysql/mysql.go
+++ b/pkg/db/v1beta1/mysql/mysql.go
@@ -65,6 +65,9 @@ func NewDBInterface(connectTimeout time.Duration) (common.KatibDBInterface, erro
 }
 
 func (d *dbConn) RegisterObservationLog(trialName string, observationLog *v1beta1.ObservationLog) error {
+	if observationLog == nil {
+		return nil
+	}
 	sqlQuery := "INSERT INTO observation_logs (trial_name, time, metric_name, value) VALUES "
 	values := []interface{}{}
 
@@ -81,6 +84,10 @@ func (d *dbConn) RegisterObservationLog(trialName string, observationLog *v1beta
 		sqlQuery += "(?, ?, ?, ?),"
 		values = append(values, trialName, sqlTimeStr, mlog.Metric.Name, mlog.Metric.Value)
 	}
+	if len(values) == 0 {
+		// No valid metric logs to insert, skip Prepare/Exec.
+		return nil
+	}
 	sqlQuery = sqlQuery[0 : len(sqlQuery)-1]
 
 	// Prepare the statement
diff --git a/pkg/db/v1beta1/mysql/mysql_test.go b/pkg/db/v1beta1/mysql/mysql_test.go
index f22df6cb896..1bbd6c0e4a6 100644
--- a/pkg/db/v1beta1/mysql/mysql_test.go
+++ b/pkg/db/v1beta1/mysql/mysql_test.go
@@ -88,6 +88,43 @@ func TestRegisterObservationLog(t *testing.T) {
 
 }
 
+func TestRegisterObservationLogNoValidEntries(t *testing.T) {
+	obsLog := &api_pb.ObservationLog{
+		MetricLogs: []*api_pb.MetricLog{
+			{
+				TimeStamp: "",
+				Metric: &api_pb.Metric{
+					Name:  "f1_score",
+					Value: "88.95",
+				},
+			},
+		},
+	}
+
+	err := dbInterface.RegisterObservationLog("test1_trial1", obsLog)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
+func TestRegisterObservationLogEmptyMetricLogs(t *testing.T) {
+	obsLog := &api_pb.ObservationLog{
+		MetricLogs: []*api_pb.MetricLog{},
+	}
+
+	err := dbInterface.RegisterObservationLog("test1_trial1", obsLog)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
+func TestRegisterObservationLogNilObservationLog(t *testing.T) {
+	err := dbInterface.RegisterObservationLog("test1_trial1", nil)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
 func TestGetObservationLog(t *testing.T) {
 	mock.ExpectQuery("SELECT").WillReturnRows(
 		sqlmock.NewRows([]string{"time", "metric_name", "value"}).AddRow(
diff --git a/pkg/db/v1beta1/postgres/postgres.go b/pkg/db/v1beta1/postgres/postgres.go
index 808af5ad93c..508d04c230a 100644
--- a/pkg/db/v1beta1/postgres/postgres.go
+++ b/pkg/db/v1beta1/postgres/postgres.go
@@ -67,6 +67,9 @@ func NewDBInterface(connectTimeout time.Duration) (common.KatibDBInterface, erro
 }
 
 func (d *dbConn) RegisterObservationLog(trialName string, observationLog *v1beta1.ObservationLog) error {
+	if observationLog == nil {
+		return nil
+	}
 	statement := "INSERT INTO observation_logs (trial_name, time, metric_name, value) VALUES "
 	values := []interface{}{}
 
@@ -88,6 +91,11 @@ func (d *dbConn) RegisterObservationLog(trialName string, observationLog *v1beta
 		index_of_qparam += 4
 	}
 
+	if len(values) == 0 {
+		// No valid metric logs to insert, skip Prepare/Exec.
+		return nil
+	}
+
 	statement = statement[:len(statement)-1]
 
 	// Prepare the statement
diff --git a/pkg/db/v1beta1/postgres/postgres_test.go b/pkg/db/v1beta1/postgres/postgres_test.go
index f478107aab2..a2083ee3beb 100644
--- a/pkg/db/v1beta1/postgres/postgres_test.go
+++ b/pkg/db/v1beta1/postgres/postgres_test.go
@@ -90,6 +90,43 @@ func TestRegisterObservationLog(t *testing.T) {
 
 }
 
+func TestRegisterObservationLogNoValidEntries(t *testing.T) {
+	obsLog := &api_pb.ObservationLog{
+		MetricLogs: []*api_pb.MetricLog{
+			{
+				TimeStamp: "",
+				Metric: &api_pb.Metric{
+					Name:  "f1_score",
+					Value: "88.95",
+				},
+			},
+		},
+	}
+
+	err := dbInterface.RegisterObservationLog("test1_trial1", obsLog)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
+func TestRegisterObservationLogEmptyMetricLogs(t *testing.T) {
+	obsLog := &api_pb.ObservationLog{
+		MetricLogs: []*api_pb.MetricLog{},
+	}
+
+	err := dbInterface.RegisterObservationLog("test1_trial1", obsLog)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
+func TestRegisterObservationLogNilObservationLog(t *testing.T) {
+	err := dbInterface.RegisterObservationLog("test1_trial1", nil)
+	if err != nil {
+		t.Errorf("RegisterObservationLog failed: %v", err)
+	}
+}
+
 func TestGetObservationLog(t *testing.T) {
 	mock.ExpectQuery("SELECT").WillReturnRows(
 		sqlmock.NewRows([]string{"time", "metric_name", "value"}).AddRow(