diff --git a/internal/master/timesync.go b/internal/master/timesync.go
index 3a883b32a12f175976930788f92ba105990eac72..6e85ecbf607a8f3ee71062b90086344164b6360d 100644
--- a/internal/master/timesync.go
+++ b/internal/master/timesync.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"log"
 	"math"
+	"sync/atomic"
 
 	"github.com/zilliztech/milvus-distributed/internal/errors"
 	ms "github.com/zilliztech/milvus-distributed/internal/msgstream"
@@ -19,12 +20,11 @@ type (
 	softTimeTickBarrier struct {
 		peer2LastTt   map[UniqueID]Timestamp
 		minTtInterval Timestamp
-		lastTt        Timestamp
+		lastTt        int64
 		outTt         chan Timestamp
 		ttStream      ms.MsgStream
 		ctx           context.Context
-		closeCh       chan struct{} // close goroutinue in Start()
-		closed        bool
+		cancel        context.CancelFunc
 	}
 
 	hardTimeTickBarrier struct {
@@ -32,46 +32,36 @@ type (
 		outTt    chan Timestamp
 		ttStream ms.MsgStream
 		ctx      context.Context
-		closeCh  chan struct{} // close goroutinue in Start()
-		closed   bool
+		cancel   context.CancelFunc
 	}
 )
 
 func (ttBarrier *softTimeTickBarrier) GetTimeTick() (Timestamp, error) {
-	isEmpty := true
-	for {
-
-		if ttBarrier.closed {
+	select {
+	case <-ttBarrier.ctx.Done():
+		return 0, errors.Errorf("[GetTimeTick] closed.")
+	case ts, ok := <-ttBarrier.outTt:
+		if !ok {
 			return 0, errors.Errorf("[GetTimeTick] closed.")
 		}
-
-		select {
-		case ts := <-ttBarrier.outTt:
-			isEmpty = false
-			ttBarrier.lastTt = ts
-
-		default:
-			if isEmpty || ttBarrier.closed {
-				continue
+		num := len(ttBarrier.outTt)
+		for i := 0; i < num; i++ {
+			ts, ok = <-ttBarrier.outTt
+			if !ok {
+				return 0, errors.Errorf("[GetTimeTick] closed.")
 			}
-			return ttBarrier.lastTt, nil
 		}
+		atomic.StoreInt64(&(ttBarrier.lastTt), int64(ts))
+		return ts, nil
 	}
 }
 
 func (ttBarrier *softTimeTickBarrier) Start() error {
-	ttBarrier.closeCh = make(chan struct{}, 1)
 	go func() {
 		for {
 			select {
-
-			case <-ttBarrier.closeCh:
-				log.Printf("[TtBarrierStart] closed\n")
-				return
-
 			case <-ttBarrier.ctx.Done():
 				log.Printf("[TtBarrierStart] %s\n", ttBarrier.ctx.Err())
-				ttBarrier.closed = true
 				return
 
 			case ttmsgs := <-ttBarrier.ttStream.Chan():
@@ -91,8 +81,8 @@ func (ttBarrier *softTimeTickBarrier) Start() error {
 
 							// get a legal Timestamp
 							ts := ttBarrier.minTimestamp()
-
-							if ttBarrier.lastTt != 0 && ttBarrier.minTtInterval > ts-ttBarrier.lastTt {
+							lastTt := atomic.LoadInt64(&(ttBarrier.lastTt))
+							if ttBarrier.lastTt != 0 && ttBarrier.minTtInterval > ts-Timestamp(lastTt) {
 								continue
 							}
 
@@ -100,8 +90,6 @@ func (ttBarrier *softTimeTickBarrier) Start() error {
 						}
 					}
 				}
-
-			default:
 			}
 		}
 	}()
@@ -122,9 +110,7 @@ func newSoftTimeTickBarrier(ctx context.Context,
 	sttbarrier.minTtInterval = minTtInterval
 	sttbarrier.ttStream = *ttStream
 	sttbarrier.outTt = make(chan Timestamp, 1024)
-	sttbarrier.ctx = ctx
-	sttbarrier.closed = false
-
+	sttbarrier.ctx, sttbarrier.cancel = context.WithCancel(ctx)
 	sttbarrier.peer2LastTt = make(map[UniqueID]Timestamp)
 	for _, id := range peerIds {
 		sttbarrier.peer2LastTt[id] = Timestamp(0)
@@ -137,12 +123,7 @@ func newSoftTimeTickBarrier(ctx context.Context,
 }
 
 func (ttBarrier *softTimeTickBarrier) Close() {
-
-	if ttBarrier.closeCh != nil {
-		ttBarrier.closeCh <- struct{}{}
-	}
-
-	ttBarrier.closed = true
+	ttBarrier.cancel()
 }
 
 func (ttBarrier *softTimeTickBarrier) minTimestamp() Timestamp {
@@ -156,36 +137,25 @@ func (ttBarrier *softTimeTickBarrier) minTimestamp() Timestamp {
 }
 
 func (ttBarrier *hardTimeTickBarrier) GetTimeTick() (Timestamp, error) {
-	for {
-
-		if ttBarrier.closed {
+	select {
+	case <-ttBarrier.ctx.Done():
+		return 0, errors.Errorf("[GetTimeTick] closed.")
+	case ts, ok := <-ttBarrier.outTt:
+		if !ok {
 			return 0, errors.Errorf("[GetTimeTick] closed.")
 		}
-
-		select {
-		case ts := <-ttBarrier.outTt:
-			return ts, nil
-		default:
-		}
+		return ts, nil
 	}
 }
 
 func (ttBarrier *hardTimeTickBarrier) Start() error {
-	ttBarrier.closeCh = make(chan struct{}, 1)
-
 	go func() {
 		// Last timestamp synchronized
 		state := Timestamp(0)
 		for {
 			select {
-
-			case <-ttBarrier.closeCh:
-				log.Printf("[TtBarrierStart] closed\n")
-				return
-
 			case <-ttBarrier.ctx.Done():
 				log.Printf("[TtBarrierStart] %s\n", ttBarrier.ctx.Err())
-				ttBarrier.closed = true
 				return
 
 			case ttmsgs := <-ttBarrier.ttStream.Chan():
@@ -217,7 +187,6 @@ func (ttBarrier *hardTimeTickBarrier) Start() error {
 						}
 					}
 				}
-			default:
 			}
 		}
 	}()
@@ -246,8 +215,7 @@ func newHardTimeTickBarrier(ctx context.Context,
 	sttbarrier := hardTimeTickBarrier{}
 	sttbarrier.ttStream = *ttStream
 	sttbarrier.outTt = make(chan Timestamp, 1024)
-	sttbarrier.ctx = ctx
-	sttbarrier.closed = false
+	sttbarrier.ctx, sttbarrier.cancel = context.WithCancel(ctx)
 
 	sttbarrier.peer2Tt = make(map[UniqueID]Timestamp)
 	for _, id := range peerIds {
@@ -261,8 +229,5 @@ func newHardTimeTickBarrier(ctx context.Context,
 }
 
 func (ttBarrier *hardTimeTickBarrier) Close() {
-	if ttBarrier.closeCh != nil {
-		ttBarrier.closeCh <- struct{}{}
-	}
-	ttBarrier.closed = true
+	ttBarrier.cancel()
 }