diff --git a/core/storage/mongoStorage.go b/core/storage/mongoStorage.go
index 1d5a437..88e6838 100644
--- a/core/storage/mongoStorage.go
+++ b/core/storage/mongoStorage.go
@@ -29,21 +29,12 @@ type gridfsFile struct {
 	Length int64  `bson:"length"`
 }
 
-type fileHandle2 struct {
-	downloadStream *gridfs.DownloadStream // have Read([]p) function
-	//uploadStream   *gridfs.UploadStream   // have Write([]p) function
-	session *mongo.Client
-	offset  int64
-	chunks  map[int64][]byte
-}
-
 // MongoStorage is a MongoDB based store
 type MongoStorage struct {
 	client            *mongo.Client
 	clientConnectOpts *options.ClientOptions
 	database          *mongo.Database
 	gridfsBucket      *gridfs.Bucket
-	openFiles         map[string]*fileHandle2
 	connected         bool
 	lockChannel       chan int
 	mapLock           chan int
@@ -86,9 +77,8 @@ type isMasterResult struct {
 }
 
 type messagingGroupObject struct {
-	ID        string `bson:"_id"`
-	GroupName string `bson:"group-name"`
-	//LastUpdate bson.MongoTimestamp `bson:"last-update"`
+	ID         string    `bson:"_id"`
+	GroupName  string    `bson:"group-name"`
 	LastUpdate time.Time `bson:"last-update"`
 }
 
@@ -145,7 +135,6 @@ func (store *MongoStorage) Init() common.SyncServiceError {
 			WriteTimeout: time.Duration(60 * time.Second),
 		}*/
 
-	//var session *mongo.Session
 	var mongoClient *mongo.Client
 	var err error
 	if trace.IsLogging(logger.INFO) {
@@ -191,7 +180,7 @@ func (store *MongoStorage) Init() common.SyncServiceError {
 	}
 
 	for connectTime := 0; connectTime < common.Configuration.DatabaseConnectTimeout; connectTime += 10 {
-		trace.Info("Lily to connect to mongo...")
+		trace.Info("connect to mongo...")
 		if mongoClient, err = mongo.Connect(ctx, clientOptions); err == nil {
 			break
 		} else {
@@ -230,9 +219,6 @@ func (store *MongoStorage) Init() common.SyncServiceError {
 		log.Info("Connected to the database")
 	}
 
-	//session.SetSafe(&mgo.Safe{})
-	//session.SetMode(mgo.Monotonic, true)
-
 	db := mongoClient.Database(common.Configuration.MongoDbName)
 	destinationsCollection := db.Collection(destinations)
 	indexModel := mongo.IndexModel{Keys: bson.D{{"destination.destination-org-id", -1}}}
@@ -285,15 +271,11 @@ func (store *MongoStorage) Init() common.SyncServiceError {
 		trace.Error("Error creating gridfs buket Error was: " + err.Error())
 	}
 
-	//session, err := mongoClient.StartSession()
 	store.client = mongoClient
 	store.database = db
 	store.gridfsBucket = gridfsBucket
 
-	//session.Client().Database(common.Configuration.MongoDbName).Collection()
-	//err = session.Client().Ping(context.Background(), nil)
-
-	store.openFiles = make(map[string]*fileHandle2)
+	//store.openFiles = make(map[string]*fileHandle2)
 
 	sleepInMS = common.Configuration.MongoSleepTimeBetweenRetry
 
@@ -335,24 +317,7 @@ func (store *MongoStorage) GetObjectsToActivate() ([]common.MetaData, common.Syn
 		"$and": bson.A{
 			bson.M{"metadata.activation-time": bson.M{"$ne": ""}},
 			bson.M{"metadata.activation-time": bson.M{"$lte": currentTime}}}}
-	//selector := bson.M{"metadata": bson.ElementDocument}
-	// filter := bson.D{
-	// 	{Key: "$or",
-	// 		Value: bson.A{
-	// 			bson.D{{Key: "status", Value: common.NotReadyToSend}},
-	// 			bson.D{{"status", common.ReadyToSend}},
-	// 			bson.D{{"status", common.Verifying}},
-	// 			bson.D{{"status", common.VerificationFailed}},
-	// 		},
-	// 	},
-	// 	{"$and",
-	// 		bson.A{
-	// 			bson.D{{"metadata.activation-time", bson.D{{"$ne", ""}}}},
-	// 			bson.D{{"metadata.activation-time", bson.D{{"$lte", currentTime}}}}
-	// 		},
-	// 	},
-	// }
-	//selector := bson.M{"metadata": bson.ElementDocument}
+
 	selector := bson.D{{"metadata", 1}}
 	result := []object{}
 	if err := store.fetchAll(objects, query, selector, &result); err != nil {
@@ -426,10 +391,6 @@ func (store *MongoStorage) StoreObject(metaData common.MetaData, data []byte, st
 		}
 	}
 
-	// newObject := object{ID: id, MetaData: metaData, Status: status, PolicyReceived: false,
-	// 	RemainingConsumers: metaData.ExpectedConsumers,
-	// 	RemainingReceivers: metaData.ExpectedConsumers, Destinations: dests}
-
 	newObj := bson.M{"$set": bson.M{"_id": id, "metadata": metaData, "status": status, "policy-received": false,
 		"remaining-consumers": metaData.ExpectedConsumers,
 		"remaining-receivers": metaData.ExpectedConsumers, "destinations": dests,
@@ -499,13 +460,11 @@ func (store *MongoStorage) UpdateObjectDestinations(orgID string, objectType str
 			return nil, "", nil, nil, err
 		}
 
-		query := bson.M{
+		update := bson.M{
 			"$set":         bson.M{"destinations": dests},
 			"$currentDate": bson.M{"last-update": bson.M{"$type": "date"}},
 		}
-		// filter := bson.D{{"species", "Ledebouria socialis"}, {"plant_id", 3}}
-		// update := bson.D{{"$set", bson.D{{"species", "Ledebouria socialis"}, {"plant_id", 3}, {"height", 8.3}}}}
-		if err := store.update(objects, bson.M{"_id": id, "last-update": result.LastUpdate}, query); err != nil {
+		if err := store.update(objects, bson.M{"_id": id, "last-update": result.LastUpdate}, update); err != nil {
 			if IsNotFound(err) {
 				time.Sleep(time.Duration(sleepInMS) * time.Millisecond)
 				continue
@@ -1065,28 +1024,13 @@ func (store *MongoStorage) RetrieveObjectData(orgID string, objectType string, o
 		id = createObjectCollectionID(orgID, objectType, objectID)
 	}
 
-	// bson.M{"filename": name}
-	// filter := bson.M{"filename": id}
-	// cursor, err := store.gridfsBucket.Find(filter)
-	// if err != nil {
-	// 	switch err {
-	// 	case mongo.ErrNoDocuments:
-	// 		return nil, nil
-	// 	default:
-	// 		return nil, &Error{fmt.Sprintf("Failed to find file to read the data. Error: %s.", err)}
-	// 	}
-	// }
-	// var foundFiles []gridfsFile
-	// if err = cursor.All(context.TODO(), &foundFiles); err != nil {
-	// 	return nil, &Error{fmt.Sprintf("Failed to find file to retrieve object data. Error: %s.", err)}
-	// }
-
-	// if len(foundFiles) == 0 {
-	// 	return nil, &Error{fmt.Sprintf("Find 0 match file to retrieve object data. Error: %s.", err)}
-	// }
-
-	// file := foundFiles[0]
-	// file.Id
+	if store.gridfsBucket == nil {
+		if bucket, err := gridfs.NewBucket(store.database); err != nil {
+			return nil, err
+		} else {
+			store.gridfsBucket = bucket
+		}
+	}
 
 	downloadStream, err := store.gridfsBucket.OpenDownloadStreamByName(id)
 	if err != nil {
@@ -1099,12 +1043,6 @@ func (store *MongoStorage) RetrieveObjectData(orgID string, objectType string, o
 			return nil, &Error{fmt.Sprintf("Failed to find file to read the data. Error: %s.", err)}
 		}
 	}
-
-	//file := downloadStream.GetFile()
-	//&fileHandle{file, session, 0, nil}
-	//fileHandle := &fileHandle2{downloadStream, store.client, 0, nil}
-
-	//store.putFileHandle(id, fileHandle)
 	return downloadStream, nil
 }
 
@@ -1113,7 +1051,6 @@ func (store *MongoStorage) CloseDataReader(dataReader io.Reader) common.SyncServ
 	switch v := dataReader.(type) {
 	case *gridfs.DownloadStream:
 		v.Close()
-		//return err
 		return nil
 	default:
 		return nil
@@ -1208,13 +1145,13 @@ func (store *MongoStorage) StoreObjectData(orgID string, objectType string, obje
 		return false, err
 	}
 
-	file, err := store.getFileInfo(id)
+	fileInfo, err := store.getFileInfo(id)
 	if err != nil {
 		return false, &Error{fmt.Sprintf("Failed to get mongo file information. Error: %s.", err)}
 	}
 
 	// Update object size
-	if err := store.update(objects, bson.M{"_id": id}, bson.M{"$set": bson.M{"metadata.object-size": file.Length}}); err != nil {
+	if err := store.update(objects, bson.M{"_id": id}, bson.M{"$set": bson.M{"metadata.object-size": fileInfo.Length}}); err != nil {
 		return false, &Error{fmt.Sprintf("Failed to update object's size. Error: %s.", err)}
 	}
 
@@ -1394,37 +1331,9 @@ func (store *MongoStorage) AppendObjectData(orgID string, objectType string, obj
 	//var fileHandle *fileHandle
 	store.removeFile(id)
 	br := bytes.NewReader(data)
-	if err = store.createAFile(id, br); err != nil {
+	if err = store.createFile(id, br); err != nil {
 		return isLastChunk, err
 	}
-	//fileHandle = fh
-	//store.putFileHandle(id, fileHandle)
-
-	/*
-		for {
-			if trace.IsLogging(logger.TRACE) {
-				trace.Trace("Put data (data size: %d) in file %s\n", len(data), id)
-			}
-			n, err = fileHandle.Write(data)
-			if err != nil {
-				return isLastChunk, &Error{fmt.Sprintf("Failed to write the data to the file. Error: %s.", err)}
-			}
-			if n != len(data) {
-				return isLastChunk, &Error{fmt.Sprintf("Failed to write all the data to the file. Wrote %d instead of %d.", n, len(data))}
-			}
-			fileHandle.offset += int64(n)
-			if fileHandle.chunks == nil {
-				break
-			}
-			data = fileHandle.chunks[fileHandle.offset]
-			if data == nil {
-				break
-			}
-			delete(fileHandle.chunks, fileHandle.offset)
-			if trace.IsLogging(logger.TRACE) {
-				trace.Trace(" Get data (%d) from map at offset %d\n", len(data), offset)
-			}
-		}*/
 
 	if updatedLastChunk {
 		if trace.IsLogging(logger.TRACE) {
@@ -1432,7 +1341,7 @@ func (store *MongoStorage) AppendObjectData(orgID string, objectType string, obj
 		}
 	}
 
-	store.deleteFileHandle(id)
+	//store.deleteFileHandle(id)
 	//err = fileHandle.Close()
 	if err != nil {
 		return updatedLastChunk, &Error{fmt.Sprintf("Failed to close the file. Error: %s.", err)}
@@ -1559,7 +1468,6 @@ func (store *MongoStorage) ActivateObject(orgID string, objectType string, objec
 
 // DeleteStoredObject deletes the object
 func (store *MongoStorage) DeleteStoredObject(orgID string, objectType string, objectID string) common.SyncServiceError {
-	//ts := primitive.Timestamp{T: 0, I: 0}
 	t := time.Date(0001, 1, 1, 00, 00, 00, 00, time.UTC)
 	return store.deleteObject(orgID, objectType, objectID, t)
 }
@@ -1759,18 +1667,9 @@ func (store *MongoStorage) DestinationExists(orgID string, destType string, dest
 // StoreDestination stores the destination
 func (store *MongoStorage) StoreDestination(destination common.Destination) common.SyncServiceError {
 	id := getDestinationCollectionID(destination)
-	//newObject := destinationObject{ID: id, Destination: destination}
-	//timestamp := primitive.Timestamp{T: uint32(time.Now().Unix())}
-
 	filter := bson.D{{"_id", id}, {"destination.destination-org-id", destination.DestOrgID}}
 	newObject := bson.D{{"$set", bson.D{{"_id", id}, {"destination", destination}, {"last-ping-time", primitive.NewDateTimeFromTime(time.Now())}}}}
-
-	// filter := bson.M{"_id": id, "destination.destination-org-id": destination.DestOrgID}
-	// newObject := bson.M{
-	// 	"$set":         bson.M{"_id": id, "destination": destination},
-	// 	"$currentDate": bson.M{"last-ping-time": bson.M{"$type": "date"}}}
 	err := store.upsert(destinations, filter, newObject)
-	//err := store.insert(destinations, newObject)
 	if err != nil {
 		return &Error{fmt.Sprintf("Failed to store a destination. Error: %s.", err)}
 	}
@@ -1805,10 +1704,6 @@ func (store *MongoStorage) UpdateDestinationLastPingTime(destination common.Dest
 
 // RemoveInactiveDestinations removes destinations that haven't sent ping since the provided timestamp
 func (store *MongoStorage) RemoveInactiveDestinations(lastTimestamp time.Time) {
-	//timestamp, err := bson.NewMongoTimestamp(lastTimestamp, 1)
-	//timestamp := primitive.Timestamp{T: uint32(lastTimestamp.Unix())}
-
-	// "lastUpdate": primitive.Timestamp{T:uint32(time.Now().Unix())}
 	query := bson.M{"last-ping-time": bson.M{"$lte": lastTimestamp}}
 	selector := bson.M{"destination": 1}
 	dests := []destinationObject{}
@@ -1966,17 +1861,10 @@ func (store *MongoStorage) UpdateRemovedDestinationPolicyServices(orgID string,
 // UpdateNotificationRecord updates/adds a notification record to the object
 func (store *MongoStorage) UpdateNotificationRecord(notification common.Notification) common.SyncServiceError {
 	id := getNotificationCollectionID(&notification)
-	//fmt.Printf("insert or update notification record: %v\n", id)
 	if notification.ResendTime == 0 {
 		resendTime := time.Now().Unix() + int64(common.Configuration.ResendInterval*6)
 		notification.ResendTime = resendTime
 	}
-
-	// filter := bson.M{"_id": id, "destination.destination-org-id": destination.DestOrgID}
-	// newObject := bson.M{"$set": bson.M{"_id": id, "destination": destination, "last-ping-time": primitive.NewDateTimeFromTime(time.Now())}}
-	// err := store.upsert(destinations, filter, newObject)
-
-	//n := notificationObject{ID: id, Notification: notification}
 	n := bson.M{"$set": bson.M{"_id": id, "notification": notification}}
 	err := store.upsert(notifications,
 		bson.M{
@@ -1986,14 +1874,12 @@ func (store *MongoStorage) UpdateNotificationRecord(notification common.Notifica
 			"notification.destination-type":   notification.DestType,
 		},
 		n)
-	//fmt.Printf("insert or update notification record error: %v", err)
 	if err != nil {
 		return &Error{fmt.Sprintf("Failed to update notification record. Error: %s.", err)}
 	}
 
 	no := notificationObject{}
 	_ = store.fetchOne(notifications, bson.M{"_id": id}, nil, &no)
-	//fmt.Printf("now fetch the notification after upsert notification record no: %v, error: %v", no, err)
 	return nil
 }
 
@@ -2050,7 +1936,6 @@ func (store *MongoStorage) RetrieveNotifications(orgID string, destType string,
 	result := []notificationObject{}
 	var query bson.M
 	if destType == "" && destID == "" {
-		//currentTime := time.Now().Unix()
 		currentTime := primitive.NewDateTimeFromTime(time.Now())
 
 		query = bson.M{"$or": bson.A{
@@ -2215,7 +2100,6 @@ func (store *MongoStorage) UpdateLeader(leaderID string, version int64) (bool, c
 
 // ResignLeadership causes this sync service to give up the Leadership
 func (store *MongoStorage) ResignLeadership(leaderID string) common.SyncServiceError {
-	//timestamp, err := bson.NewMongoTimestamp(time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC), 1)
 	timestamp := time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC)
 
 	err := store.update(leader,
@@ -2255,7 +2139,6 @@ func (store *MongoStorage) RetrieveTimeOnServer() (time.Time, error) {
 		ok: 1
 		}
 	*/
-	// TODO: is it okay to use isMasterResult{} as result type??
 	result := isMasterResult{}
 	err := store.run(bson.D{{"isMaster", 1}}, &result)
 	if err == nil && !result.OK {
@@ -2266,9 +2149,6 @@ func (store *MongoStorage) RetrieveTimeOnServer() (time.Time, error) {
 
 // StoreOrgToMessagingGroup inserts organization to messaging groups table
 func (store *MongoStorage) StoreOrgToMessagingGroup(orgID string, messagingGroup string) common.SyncServiceError {
-	//object := messagingGroupObject{ID: orgID, GroupName: messagingGroup}
-	// t := time.Now()
-	// primitive.NewDateTimeFromTime(t)
 	mg := bson.M{"$set": bson.M{"_id": orgID, "group-name": messagingGroup, "last-update": primitive.NewDateTimeFromTime(time.Now())}}
 	err := store.upsert(messagingGroups, bson.M{"_id": orgID}, mg)
 	if err != nil {
@@ -2300,8 +2180,6 @@ func (store *MongoStorage) RetrieveMessagingGroup(orgID string) (string, common.
 // RetrieveUpdatedMessagingGroups retrieves messaging groups that were updated after the specified time
 func (store *MongoStorage) RetrieveUpdatedMessagingGroups(timeToCheck time.Time) ([]common.MessagingGroup,
 	common.SyncServiceError) {
-	//timestamp, err := bson.NewMongoTimestamp(time, 1)
-	//timestamp := primitive.Timestamp{T: uint32(timeToCheck.Unix())}
 
 	result := []messagingGroupObject{}
 	if err := store.fetchAll(messagingGroups, bson.M{"last-update": bson.M{"$gte": timeToCheck}}, nil, &result); err != nil {
diff --git a/core/storage/mongoStorageHelpers.go b/core/storage/mongoStorageHelpers.go
index 299d565..adf8332 100644
--- a/core/storage/mongoStorageHelpers.go
+++ b/core/storage/mongoStorageHelpers.go
@@ -73,8 +73,6 @@ func (store *MongoStorage) deleteObject(orgID string, objectType string, objectI
 	}
 
 	query := bson.M{"_id": id}
-	//if timestamp != -1
-	// now check if timestamp is zero, not check against -1
 	if !timestamp.IsZero() {
 		query = bson.M{"_id": id, "last-update": timestamp}
 	}
@@ -97,7 +95,7 @@ func (store *MongoStorage) deleteObject(orgID string, objectType string, objectI
 // append data stream to mongodb data
 func (store *MongoStorage) copyDataToFile(id string, dataReader io.Reader) (err common.SyncServiceError) {
 	store.removeFile(id)
-	err = store.createAFile(id, dataReader)
+	err = store.createFile(id, dataReader)
 	if err != nil {
 		err = &Error{fmt.Sprintf("Failed to create file to store the data. Error: %s.", err)}
 		return
@@ -110,7 +108,7 @@ func (store *MongoStorage) copyDataToFile(id string, dataReader io.Reader) (err
 func (store *MongoStorage) storeDataInFile(id string, data []byte) common.SyncServiceError {
 	store.removeFile(id)
 	br := bytes.NewReader(data)
-	if err := store.createAFile(id, br); err != nil {
+	if err := store.createFile(id, br); err != nil {
 		return &Error{fmt.Sprintf("Failed to create file to store the data. Error: %s.", err)}
 	}
 	return nil
@@ -170,7 +168,7 @@ func (store *MongoStorage) removeAll(collectionName string, query interface{}) c
 func (store *MongoStorage) fetchAll(collectionName string, query interface{}, selector interface{}, result interface{}) common.SyncServiceError {
 	function := func(collection *mongo.Collection) error {
 		opts := options.Find().SetProjection(selector)
-		// selector looks like: bson.D{{"title", 1}, {"enrollment", 1}}, 1 means include
+		// selector looks like: bson.D{{"field1", 1}, {"field2", 1}}, 1 means include
 
 		cursor, err := collection.Find(context.TODO(), query, opts)
 		if err != nil {
@@ -194,21 +192,13 @@ func (store *MongoStorage) fetchAll(collectionName string, query interface{}, se
 func (store *MongoStorage) fetchOne(collectionName string, query interface{}, selector interface{}, result interface{}) common.SyncServiceError {
 	function := func(collection *mongo.Collection) error {
 		opts := options.FindOne()
-		//err := coll.FindOne(context.TODO(), filter, opts).Decode(&result)
-		err := collection.FindOne(context.TODO(), query, opts).Decode(result)
-		//if collection.Name() == notifications {
-		//fmt.Printf("collectionname: %v, result1: %v, err: %v\n", collection.Name(), result, err)
-		//}
-
-		//fmt.Printf("result1: %v, err: %v\n", result, err)
-		return err
+		return collection.FindOne(context.TODO(), query, opts).Decode(result)
 	}
 
 	retry, err := store.withCollectionHelper(collectionName, function, true)
 	if err != nil {
 		return err
 	}
-	//fmt.Printf("result2: %v\n", result)
 
 	if retry {
 		return store.fetchOne(collectionName, query, selector, result)
@@ -219,9 +209,6 @@ func (store *MongoStorage) fetchOne(collectionName string, query interface{}, se
 func (store *MongoStorage) update(collectionName string, filter interface{}, update interface{}) common.SyncServiceError {
 	function := func(collection *mongo.Collection) error {
 		opts := options.Update()
-		// filter := bson.D{{"species", "Ledebouria socialis"}, {"plant_id", 3}}
-		// update := bson.D{{"$set", bson.D{{"species", "Ledebouria socialis"}, {"plant_id", 3}, {"height", 8.3}}}}
-
 		updatedResult, err := collection.UpdateOne(context.TODO(), filter, update, opts)
 		v := int64(0)
 		if updatedResult.MatchedCount == v {
@@ -368,7 +355,7 @@ func (store *MongoStorage) openFile(id string) (*gridfs.DownloadStream, common.S
 }
 
 // Save file into mongo gridFS
-func (store *MongoStorage) createAFile(id string, data io.Reader) common.SyncServiceError {
+func (store *MongoStorage) createFile(id string, data io.Reader) common.SyncServiceError {
 
 	function := func(db *mongo.Database) (*gridfs.DownloadStream, error) {
 		var err error
@@ -391,17 +378,14 @@ func (store *MongoStorage) createAFile(id string, data io.Reader) common.SyncSer
 	}
 
 	if retry {
-		return store.createAFile(id, data)
+		return store.createFile(id, data)
 	}
 
 	return nil
 }
 
 func (store *MongoStorage) run(cmd interface{}, result interface{}) common.SyncServiceError {
-	// db.runCommand( { isMaster: 1 } )
-	//cmd = bson.D{{"isMaster", 1}}
 	function := func(db *mongo.Database) error {
-		//var result bson.M
 		return db.RunCommand(context.TODO(), cmd).Decode(&result)
 	}
 
@@ -440,7 +424,6 @@ func (store *MongoStorage) withDBHelper(function func(*mongo.Database) error, is
 	}
 
 	// reach here if has ping err
-	//session.Refresh()
 	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(20*time.Second))
 	defer cancel()
 	mongoClient, err = mongo.Connect(ctx, store.clientConnectOpts)
@@ -450,7 +433,6 @@ func (store *MongoStorage) withDBHelper(function func(*mongo.Database) error, is
 	pingErr = mongoClient.Ping(context.Background(), nil)
 	if pingErr == nil {
 		db := mongoClient.Database(common.Configuration.MongoDbName)
-		// TODO: put this new created mongoClient into sessionCache
 		store.database = db
 		gridfsBucket, err := gridfs.NewBucket(db)
 		if err != nil {
@@ -503,7 +485,6 @@ func (store *MongoStorage) withDBAndReturnHelper(function func(*mongo.Database)
 	}
 
 	// reach here if has ping err
-	//session.Refresh()
 	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(20*time.Second))
 	defer cancel()
 	mongoClient, err = mongo.Connect(ctx, store.clientConnectOpts)
@@ -513,7 +494,6 @@ func (store *MongoStorage) withDBAndReturnHelper(function func(*mongo.Database)
 	pingErr = mongoClient.Ping(context.Background(), nil)
 	if pingErr == nil {
 		db := mongoClient.Database(common.Configuration.MongoDbName)
-		// TODO: put this new created mongoClient into sessionCache
 		store.database = db
 		gridfsBucket, err := gridfs.NewBucket(db)
 		if err != nil {
@@ -565,7 +545,6 @@ func (store *MongoStorage) withCollectionHelper(collectionName string, function
 	}
 
 	// reach here if has ping err
-	//session.Refresh()
 	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(20*time.Second))
 	defer cancel()
 	mongoClient, err = mongo.Connect(ctx, store.clientConnectOpts)
@@ -575,16 +554,14 @@ func (store *MongoStorage) withCollectionHelper(collectionName string, function
 	pingErr = mongoClient.Ping(context.Background(), nil)
 
 	if pingErr == nil {
-		collection = mongoClient.Database(common.Configuration.MongoDbName).Collection(collectionName)
-		// TODO: put this new created mongoClient into sessionCache?
-
-		// db := mongoClient.Database(common.Configuration.MongoDbName)
-		// store.database = db
-		// gridfsBucket, err := gridfs.NewBucket(db)
-		// if err != nil {
-		// 	return nil, false, nil
-		// }
-		// store.gridfsBucket = gridfsBucket
+		db := mongoClient.Database(common.Configuration.MongoDbName)
+		store.database = db
+		gridfsBucket, err := gridfs.NewBucket(db)
+		if err != nil {
+			return false, nil
+		}
+		store.gridfsBucket = gridfsBucket
+		collection = db.Collection(collectionName)
 
 		err = function(collection)
 		if err == nil || err == mongo.ErrNoDocuments || IsNotFound(err) || err == mongo.ErrNilCursor || mongo.IsDuplicateKeyError(err) {
@@ -679,25 +656,6 @@ func (store *MongoStorage) unLock() {
 	store.lockChannel <- 1
 }
 
-func (store *MongoStorage) getFileHandle(id string) (fH *fileHandle2) {
-	<-store.mapLock
-	fH = store.openFiles[id]
-	store.mapLock <- 1
-	return
-}
-
-func (store *MongoStorage) putFileHandle(id string, fH *fileHandle2) {
-	<-store.mapLock
-	store.openFiles[id] = fH
-	store.mapLock <- 1
-}
-
-func (store *MongoStorage) deleteFileHandle(id string) {
-	<-store.mapLock
-	delete(store.openFiles, id)
-	store.mapLock <- 1
-}
-
 func (store *MongoStorage) addUsersToACLHelper(collection string, aclType string, orgID string, key string, users []common.ACLentry) common.SyncServiceError {
 	var id string
 	if key == "" {