fix persistence unmarshalling issue

pkg/bbgo/reflect.go

@@ -72,9 +72,6 @@ func iterateFieldsByTag(obj interface{}, tagName string, cb StructFieldIterator)
 		fv := sv.Field(i)
 		ft := st.Field(i)
 
-		fvt := fv.Type()
-		_ = fvt
-
 		// skip unexported fields
 		if !st.Field(i).IsExported() {
 			continue

pkg/service/persistence_redis.go

@@ -63,7 +63,8 @@ func (store *RedisStore) Load(val interface{}) error {
 		return err
 	}
 
-	if len(data) == 0 {
+	// skip null data
+	if len(data) == 0 || data == "null" {
 		return ErrPersistenceNotExists
 	}
 

pkg/strategy/pivotshort/strategy.go

@@ -216,6 +216,10 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 		s.Position = types.NewPositionFromMarket(s.Market)
 	}
 
+	if s.ProfitStats == nil {
+		s.ProfitStats = types.NewProfitStats(s.Market)
+	}
+
 	instanceID := s.InstanceID()
 
 	// Always update the position fields