diff --git a/pkg/source/pulsar.go b/pkg/source/pulsar.go
index 7dab3e5..7024b87 100644
--- a/pkg/source/pulsar.go
+++ b/pkg/source/pulsar.go
@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"os"
+	"sync"
 	"time"
 
 	"github.com/apache/pulsar-client-go/pulsar"
@@ -165,10 +166,11 @@ type PulsarConsumerSource struct {
 	PulsarReplicateState bool
 	PulsarMaxReconnect   *uint
 
-	client      pulsar.Client
-	consumer    pulsar.Consumer
-	log         *logrus.Entry
-	ackTrackers map[string]*ackTracker
+	client   pulsar.Client
+	consumer pulsar.Consumer
+	log      *logrus.Entry
+
+	ackTrackers *ackTrackers
 }
 
 func (p *PulsarConsumerSource) Capture(cp cursor.Checkpoint) (changes chan Change, err error) {
@@ -195,7 +197,7 @@ func (p *PulsarConsumerSource) Capture(cp cursor.Checkpoint) (changes chan Chang
 		return nil, err
 	}
 
-	p.ackTrackers = make(map[string]*ackTracker, AckTrackerSize)
+	p.ackTrackers = newAckTrackers()
 
 	p.log = logrus.WithFields(logrus.Fields{
 		"From":           "PulsarConsumerSource",
@@ -230,13 +232,11 @@ func (p *PulsarConsumerSource) Capture(cp cursor.Checkpoint) (changes chan Chang
 			first = true
 		}
 
+		// we only need to track the ack for batched message
+		// because pulsar will ack the whole batch if ack the first message
 		if msg.ID().BatchSize() > 1 {
-			key := p.ackTrackerKey(msg.ID())
-			if _, ok := p.ackTrackers[key]; !ok {
-				p.ackTrackers[key] = newAckTracker(uint(msg.ID().BatchSize()))
-			}
+			p.ackTrackers.tryAdd(msg.ID())
 		}
-
 		change = Change{Checkpoint: checkpoint, Message: m}
 		return
 	}, func() {
@@ -249,11 +249,10 @@ func (p *PulsarConsumerSource) Capture(cp cursor.Checkpoint) (changes chan Chang
 
 func (p *PulsarConsumerSource) Commit(cp cursor.Checkpoint) {
 	if mid, err := pulsar.DeserializeMessageID(cp.Data); err == nil {
-		tracker, ok := p.ackTrackers[p.ackTrackerKey(mid)]
-		if ok && tracker.ack(int(mid.BatchIdx())) {
+		// only ack the batch if all messages in the batch are acked
+		if ack, exist := p.ackTrackers.tryAck(mid); ack && exist {
 			_ = p.consumer.AckID(mid)
-			delete(p.ackTrackers, p.ackTrackerKey(mid))
-		} else if !ok {
+		} else if !ack && !exist {
 			_ = p.consumer.AckID(mid)
 		}
 	}
@@ -272,6 +271,7 @@ func (p *PulsarConsumerSource) ackTrackerKey(id pulsar.MessageID) string {
 type ackTracker struct {
 	size     uint
 	batchIDs *bitset.BitSet
+	mu       sync.Mutex
 }
 
 func newAckTracker(size uint) *ackTracker {
@@ -286,9 +286,45 @@ func newAckTracker(size uint) *ackTracker {
 }
 
 func (t *ackTracker) ack(batchID int) bool {
+	t.mu.Lock()
+	defer t.mu.Unlock()
 	if batchID < 0 {
 		return true
 	}
 	t.batchIDs.Clear(uint(batchID))
 	return t.batchIDs.None()
 }
+
+type ackTrackers struct {
+	trackers sync.Map
+}
+
+func newAckTrackers() *ackTrackers {
+	return &ackTrackers{}
+}
+
+func (a *ackTrackers) key(msg pulsar.MessageID) string {
+	return fmt.Sprintf("%d:%d", msg.LedgerID(), msg.EntryID())
+}
+
+func (a *ackTrackers) tryAdd(msg pulsar.MessageID) (ok bool) {
+	key := a.key(msg)
+	_, ok = a.trackers.Load(key)
+	if !ok {
+		_, ok = a.trackers.LoadOrStore(key, newAckTracker(uint(msg.BatchSize())))
+	}
+	return !ok
+}
+
+func (a *ackTrackers) tryAck(msg pulsar.MessageID) (success bool, exist bool) {
+	key := a.key(msg)
+	v, ok := a.trackers.Load(key)
+	if ok {
+		tracker := v.(*ackTracker)
+		success, exist = tracker.ack(int(msg.BatchIdx())), ok
+		if success {
+			_, exist = a.trackers.LoadAndDelete(key)
+		}
+	}
+	return
+}