diff --git a/pkg/bbgo/injection.go b/pkg/bbgo/injection.go
index 03ff9fd7f..cf9c47d42 100644
--- a/pkg/bbgo/injection.go
+++ b/pkg/bbgo/injection.go
@@ -84,6 +84,8 @@ func parseStructAndInject(f interface{}, objects ...interface{}) error {
 			continue
 		}
 
+		fieldName := st.Field(i).Name
+
 		switch k := fv.Kind(); k {
 
 		case reflect.Ptr, reflect.Struct:
@@ -99,12 +101,18 @@ func parseStructAndInject(f interface{}, objects ...interface{}) error {
 						return fmt.Errorf("field %v of %s can not be set to %s, make sure it is an exported field", fv, sv.Type(), ot)
 					}
 
-					if k == reflect.Ptr && ot.Kind() == reflect.Struct {
-						fv.Set(reflect.ValueOf(obj).Addr())
-					} else {
-						fv.Set(reflect.ValueOf(obj))
+					if k == reflect.Ptr && !fv.IsNil() {
+						logrus.Debugf("[injection] field %s is not nil, not injecting", fieldName)
+						continue
 					}
 
+					if k == reflect.Ptr && ot.Kind() == reflect.Struct {
+						logrus.Debugf("[injection] found ptr + struct, injecting field %s to %T", fieldName, obj)
+						fv.Set(reflect.ValueOf(obj).Addr())
+					} else {
+						logrus.Debugf("[injection] injecting field %s to %T", fieldName, obj)
+						fv.Set(reflect.ValueOf(obj))
+					}
 				}
 			}
 
diff --git a/pkg/bbgo/persistence.go b/pkg/bbgo/persistence.go
index 665813b35..7dde77f61 100644
--- a/pkg/bbgo/persistence.go
+++ b/pkg/bbgo/persistence.go
@@ -3,8 +3,9 @@ package bbgo
 import (
 	"fmt"
 
-	"github.com/c9s/bbgo/pkg/service"
 	log "github.com/sirupsen/logrus"
+
+	"github.com/c9s/bbgo/pkg/service"
 )
 
 type PersistenceSelector struct {
@@ -48,6 +49,8 @@ func (p *Persistence) Load(val interface{}, subIDs ...string) error {
 		return err
 	}
 
+	log.Debugf("using persistence store %T for loading", ps)
+
 	if p.PersistenceSelector.StoreID == "" {
 		p.PersistenceSelector.StoreID = "default"
 	}
@@ -62,6 +65,8 @@ func (p *Persistence) Save(val interface{}, subIDs ...string) error {
 		return err
 	}
 
+	log.Debugf("using persistence store %T for storing", ps)
+
 	if p.PersistenceSelector.StoreID == "" {
 		p.PersistenceSelector.StoreID = "default"
 	}
diff --git a/pkg/bbgo/trader.go b/pkg/bbgo/trader.go
index f5d1736de..c6eefb2c1 100644
--- a/pkg/bbgo/trader.go
+++ b/pkg/bbgo/trader.go
@@ -219,7 +219,7 @@ func (trader *Trader) RunSingleExchangeStrategy(ctx context.Context, strategy Si
 		return errors.New("strategy object is not a struct")
 	}
 
-	if err := trader.injectCommonServices(strategy) ; err != nil {
+	if err := trader.injectCommonServices(strategy); err != nil {
 		return err
 	}
 
@@ -337,7 +337,7 @@ func (trader *Trader) Run(ctx context.Context) error {
 			continue
 		}
 
-		if err := trader.injectCommonServices(strategy) ; err != nil {
+		if err := trader.injectCommonServices(strategy); err != nil {
 			return err
 		}
 
@@ -361,6 +361,29 @@ func (trader *Trader) injectCommonServices(s interface{}) error {
 		Facade:              persistenceFacade,
 	}
 
+	// a special injection for persistence selector:
+	// if user defined the selector, the facade pointer will be nil, hence we need to update the persistence facade pointer
+	sv := reflect.ValueOf(s).Elem()
+	if field, ok := hasField(sv, "Persistence"); ok {
+		// the selector is set, but we need to update the facade pointer
+		if !field.IsNil() {
+			elem := field.Elem()
+			if elem.Kind() != reflect.Struct {
+				return fmt.Errorf("field Persistence is not a struct element, %s given", field)
+			}
+
+			if err := injectField(elem, "Facade", persistenceFacade, true); err != nil {
+				return err
+			}
+
+			/*
+				if err := parseStructAndInject(field.Interface(), persistenceFacade); err != nil {
+					return err
+				}
+			*/
+		}
+	}
+
 	return parseStructAndInject(s,
 		&trader.Graceful,
 		&trader.logger,
@@ -371,11 +394,10 @@ func (trader *Trader) injectCommonServices(s interface{}) error {
 		trader.environment.AccountService,
 		trader.environment,
 		persistence,
-		persistenceFacade,
+		persistenceFacade, // if the strategy use persistence facade separately
 	)
 }
 
-
 // ReportPnL configure and set the PnLReporter with the given notifier
 func (trader *Trader) ReportPnL() *PnLReporterManager {
 	return NewPnLReporter(&trader.environment.Notifiability)
diff --git a/pkg/strategy/bollmaker/strategy.go b/pkg/strategy/bollmaker/strategy.go
index 22d0ba941..e1b50ef80 100644
--- a/pkg/strategy/bollmaker/strategy.go
+++ b/pkg/strategy/bollmaker/strategy.go
@@ -242,9 +242,9 @@ func (s *Strategy) ClosePosition(ctx context.Context, percentage fixedpoint.Valu
 func (s *Strategy) SaveState() error {
 	if err := s.Persistence.Save(s.state, ID, s.Symbol, stateKey); err != nil {
 		return err
-	} else {
-		log.Infof("state is saved => %+v", s.state)
 	}
+
+	log.Infof("state is saved => %+v", s.state)
 	return nil
 }