diff --git a/pkg/bbgo/cache.go b/pkg/bbgo/cache.go
index f700d012c..8a4ca3fcf 100644
--- a/pkg/bbgo/cache.go
+++ b/pkg/bbgo/cache.go
@@ -1,13 +1,17 @@
 package bbgo
 
 import (
+	"context"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path"
 	"reflect"
 
 	"github.com/pkg/errors"
+
+	"github.com/c9s/bbgo/pkg/types"
 )
 
 type DataFetcher func() (interface{}, error)
@@ -56,3 +60,11 @@ func WithCache(key string, obj interface{}, fetcher DataFetcher) error {
 
 	return nil
 }
+
+func LoadExchangeMarketsWithCache(ctx context.Context, ex types.Exchange) (markets types.MarketMap, err error) {
+	err = WithCache(fmt.Sprintf("%s-markets", ex.Name()), &markets, func() (interface{}, error) {
+		return ex.QueryMarkets(ctx)
+	})
+	return markets, err
+}
+
diff --git a/pkg/bbgo/environment.go b/pkg/bbgo/environment.go
index 05d3fb447..0d2fb75d0 100644
--- a/pkg/bbgo/environment.go
+++ b/pkg/bbgo/environment.go
@@ -441,9 +441,24 @@ func (environ *Environment) Connect(ctx context.Context) error {
 	return nil
 }
 
-func LoadExchangeMarketsWithCache(ctx context.Context, ex types.Exchange) (markets types.MarketMap, err error) {
-	err = WithCache(fmt.Sprintf("%s-markets", ex.Name()), &markets, func() (interface{}, error) {
-		return ex.QueryMarkets(ctx)
-	})
-	return markets, err
+func (environ *Environment) SyncSession(ctx context.Context, session *ExchangeSession, startTime time.Time, defaultSymbols ...string) error {
+	symbols, err := getSessionSymbols(session, defaultSymbols...)
+	if err != nil {
+		return err
+	}
+
+	return environ.TradeSync.SyncSessionSymbols(ctx, session.Exchange, startTime, symbols...)
 }
+
+func getSessionSymbols(session *ExchangeSession, defaultSymbols ...string) ([]string, error) {
+	if session.IsolatedMargin {
+		return []string{session.IsolatedMarginSymbol}, nil
+	}
+
+	if len(defaultSymbols) > 0 {
+		return defaultSymbols, nil
+	}
+
+	return session.FindPossibleSymbols()
+}
+
diff --git a/pkg/bbgo/session.go b/pkg/bbgo/session.go
index 7d45a9c24..600f9df19 100644
--- a/pkg/bbgo/session.go
+++ b/pkg/bbgo/session.go
@@ -11,6 +11,7 @@ import (
 	"github.com/c9s/bbgo/pkg/indicator"
 	"github.com/c9s/bbgo/pkg/service"
 	"github.com/c9s/bbgo/pkg/types"
+	"github.com/c9s/bbgo/pkg/util"
 )
 
 type StandardIndicatorSet struct {
@@ -522,3 +523,46 @@ func (session *ExchangeSession) UpdatePrices(ctx context.Context) (err error) {
 	session.lastPriceUpdatedAt = time.Now()
 	return err
 }
+
+func (session *ExchangeSession) FindPossibleSymbols() (symbols []string, err error) {
+	// If the session is an isolated margin session, there will be only the isolated margin symbol
+	if session.IsolatedMargin {
+		return []string{
+			session.IsolatedMarginSymbol,
+		}, nil
+	}
+
+	var balances = session.Account.Balances()
+	var fiatCurrencies = []string{"USDC", "USDT", "USD", "TWD", "EUR", "GBP"}
+	var fiatAssets []string
+
+	for _, currency := range fiatCurrencies {
+		if balance, ok := balances[currency]; ok && balance.Total() > 0 {
+			fiatAssets = append(fiatAssets, currency)
+		}
+	}
+
+	var symbolMap = map[string]struct{}{}
+
+	for _, market := range session.Markets() {
+		// ignore the markets that are not fiat currency markets
+		if !util.StringSliceContains(fiatAssets, market.QuoteCurrency) {
+			continue
+		}
+
+		// ignore the asset that we don't have in the balance sheet
+		balance, hasAsset := balances[market.BaseCurrency]
+		if !hasAsset || balance.Total() == 0 {
+			continue
+		}
+
+		symbolMap[market.Symbol] = struct{}{}
+	}
+
+	for s := range symbolMap {
+		symbols = append(symbols, s)
+	}
+
+	return symbols, nil
+}
+
diff --git a/pkg/bbgo/sync.go b/pkg/bbgo/sync.go
new file mode 100644
index 000000000..920078f66
--- /dev/null
+++ b/pkg/bbgo/sync.go
@@ -0,0 +1,2 @@
+package bbgo
+
diff --git a/pkg/cmd/sync.go b/pkg/cmd/sync.go
index c21c92cf1..af6fb8a4d 100644
--- a/pkg/cmd/sync.go
+++ b/pkg/cmd/sync.go
@@ -102,7 +102,7 @@ var SyncCmd = &cobra.Command{
 				return err
 			}
 
-			if err := environ.TradeSync.SyncSession(ctx, session, startTime, defaultSymbols...) ; err != nil {
+			if err := environ.SyncSession(ctx, session, startTime, defaultSymbols...) ; err != nil {
 				return err
 			}
 
diff --git a/pkg/service/sync.go b/pkg/service/sync.go
index 2c7c2b2c6..018af5fb4 100644
--- a/pkg/service/sync.go
+++ b/pkg/service/sync.go
@@ -6,8 +6,7 @@ import (
 
 	"github.com/sirupsen/logrus"
 
-	"github.com/c9s/bbgo/pkg/bbgo"
-	batch2 "github.com/c9s/bbgo/pkg/exchange/batch"
+	"github.com/c9s/bbgo/pkg/exchange/batch"
 	"github.com/c9s/bbgo/pkg/types"
 )
 
@@ -41,8 +40,8 @@ func (s *SyncService) SyncOrders(ctx context.Context, exchange types.Exchange, s
 		logrus.Infof("found last order, start from lastID = %d since %s", lastID, startTime)
 	}
 
-	batch := &batch2.ExchangeBatchProcessor{Exchange: exchange}
-	ordersC, errC := batch.BatchQueryClosedOrders(ctx, symbol, startTime, time.Now(), lastID)
+	b := &batch.ExchangeBatchProcessor{Exchange: exchange}
+	ordersC, errC := b.BatchQueryClosedOrders(ctx, symbol, startTime, time.Now(), lastID)
 	for order := range ordersC {
 		select {
 
@@ -97,8 +96,8 @@ func (s *SyncService) SyncTrades(ctx context.Context, exchange types.Exchange, s
 		logrus.Debugf("found last trade, start from lastID = %d since %s", lastTrade.ID, startTime)
 	}
 
-	batch := &batch2.ExchangeBatchProcessor{Exchange: exchange}
-	tradeC, errC := batch.BatchQueryTrades(ctx, symbol, &types.TradeQueryOptions{
+	b := &batch.ExchangeBatchProcessor{Exchange: exchange}
+	tradeC, errC := b.BatchQueryTrades(ctx, symbol, &types.TradeQueryOptions{
 		StartTime:   &startTime,
 		LastTradeID: lastTradeID,
 	})
@@ -133,88 +132,17 @@ func (s *SyncService) SyncTrades(ctx context.Context, exchange types.Exchange, s
 	return <-errC
 }
 
-
 // SyncSessionSymbols syncs the trades from the given exchange session
-func (s *SyncService) SyncSessionSymbols(ctx context.Context, session *bbgo.ExchangeSession, startTime time.Time, symbols ...string) error {
+func (s *SyncService) SyncSessionSymbols(ctx context.Context, exchange types.Exchange, startTime time.Time, symbols ...string) error {
 	for _, symbol := range symbols {
-		logrus.Debugf("syncing trades from exchange session %s...", session.Name)
-		if err := s.SyncTrades(ctx, session.Exchange, symbol, startTime); err != nil {
+		if err := s.SyncTrades(ctx, exchange, symbol, startTime); err != nil {
 			return err
 		}
 
-		logrus.Debugf("syncing orders from exchange session %s...", session.Name)
-		if err := s.SyncOrders(ctx, session.Exchange, symbol, startTime); err != nil {
+		if err := s.SyncOrders(ctx, exchange, symbol, startTime); err != nil {
 			return err
 		}
 	}
 
 	return nil
 }
-
-func (s *SyncService) SyncSession(ctx context.Context, session *bbgo.ExchangeSession, startTime time.Time, defaultSymbols ...string) error {
-	symbols, err := getSessionSymbols(session, defaultSymbols...)
-	if err != nil {
-		return err
-	}
-
-	return s.SyncSessionSymbols(ctx, session, startTime, symbols...)
-}
-
-func getSessionSymbols(session *bbgo.ExchangeSession, defaultSymbols ...string) ([]string, error) {
-	if session.IsolatedMargin {
-		return []string{session.IsolatedMarginSymbol}, nil
-	}
-
-	if len(defaultSymbols) > 0 {
-		return defaultSymbols, nil
-	}
-
-	return FindPossibleSymbols(session)
-}
-
-
-func FindPossibleSymbols(session *bbgo.ExchangeSession) (symbols []string, err error) {
-	var balances = session.Account.Balances()
-	var fiatCurrencies = []string{"USDC", "USDT", "USD", "TWD", "EUR", "GBP"}
-	var fiatAssets []string
-
-	for _, currency := range fiatCurrencies {
-		if balance, ok := balances[currency]; ok && balance.Total() > 0 {
-			fiatAssets = append(fiatAssets, currency)
-		}
-	}
-
-	var symbolMap = map[string]struct{}{}
-
-	for _, market := range session.Markets() {
-		// ignore the markets that are not fiat currency markets
-		if !stringSliceContains(fiatAssets, market.QuoteCurrency) {
-			continue
-		}
-
-		// ignore the asset that we don't have in the balance sheet
-		balance, hasAsset := balances[market.BaseCurrency]
-		if !hasAsset || balance.Total() == 0 {
-			continue
-		}
-
-		symbolMap[market.Symbol] = struct{}{}
-	}
-
-	for s := range symbolMap {
-		symbols = append(symbols, s)
-	}
-
-	return symbols, nil
-}
-
-
-func stringSliceContains(slice []string, needle string) bool {
-	for _, s := range slice {
-		if s == needle {
-			return true
-		}
-	}
-
-	return false
-}
diff --git a/pkg/util/string.go b/pkg/util/string.go
new file mode 100644
index 000000000..d4e446ffa
--- /dev/null
+++ b/pkg/util/string.go
@@ -0,0 +1,11 @@
+package util
+
+func StringSliceContains(slice []string, needle string) bool {
+	for _, s := range slice {
+		if s == needle {
+			return true
+		}
+	}
+
+	return false
+}