diff --git a/cdc/kv/client.go b/cdc/kv/client.go
index dcd4835497a..8e2aad17c49 100644
--- a/cdc/kv/client.go
+++ b/cdc/kv/client.go
@@ -56,8 +56,11 @@ const (
 	tikvRequestMaxBackoff     = 20000   // Maximum total sleep time(in ms)
 	grpcInitialWindowSize     = 1 << 30 // The value for initial window size on a stream
 	grpcInitialConnWindowSize = 1 << 30 // The value for initial window size on a connection
-	grpcInitialMaxRecvMsgSize = 1 << 30 // The maximum message size the client can receive
+	grpcMaxCallRecvMsgSize    = 1 << 30 // The maximum message size the client can receive
 	grpcConnCount             = 10
+
+	// The threshold of warning a message is too large. TiKV split events into 6MB per-message.
+	warnRecvMsgSizeThreshold = 12 * 1024 * 1024
 )
 
 type singleRegionInfo struct {
@@ -192,7 +195,7 @@ func (a *connArray) Init(ctx context.Context) error {
 			grpcTLSOption,
 			grpc.WithInitialWindowSize(grpcInitialWindowSize),
 			grpc.WithInitialConnWindowSize(grpcInitialConnWindowSize),
-			grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(grpcInitialMaxRecvMsgSize)),
+			grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(grpcMaxCallRecvMsgSize)),
 			grpc.WithConnectParams(grpc.ConnectParams{
 				Backoff: gbackoff.Config{
 					BaseDelay:  time.Second,
@@ -207,7 +210,6 @@ func (a *connArray) Init(ctx context.Context) error {
 				Timeout:             3 * time.Second,
 				PermitWithoutStream: true,
 			}),
-			grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(128*1024*1024)),
 		)
 		cancel()
 
@@ -1063,6 +1065,17 @@ func (s *eventFeedSession) receiveFromStream(
 			return nil
 		}
 
+		size := cevent.Size()
+		if size > warnRecvMsgSizeThreshold {
+			regionCount := 0
+			if cevent.ResolvedTs != nil {
+				regionCount = len(cevent.ResolvedTs.Regions)
+			}
+			log.Warn("change data event size too large",
+				zap.Int("size", size), zap.Int("event length", len(cevent.Events)),
+				zap.Int("resolved region count", regionCount))
+		}
+
 		for _, event := range cevent.Events {
 			state, ok := regionStates[event.RegionId]
 			// Every region's range is locked before sending requests and unlocked after exiting, and the requestID
diff --git a/cdc/kv/client_test.go b/cdc/kv/client_test.go
index ec34baf79a0..da78b8303ea 100644
--- a/cdc/kv/client_test.go
+++ b/cdc/kv/client_test.go
@@ -15,7 +15,6 @@ package kv
 
 import (
 	"context"
-	"fmt"
 	"net"
 	"sync"
 	"testing"
@@ -91,10 +90,12 @@ func (s *mockChangeDataService) EventFeed(server cdcpb.ChangeData_EventFeedServe
 	return nil
 }
 
-func newMockService(c *check.C, port int, ch chan *cdcpb.ChangeDataEvent, wg *sync.WaitGroup) *grpc.Server {
-	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
+func newMockService(ctx context.Context, c *check.C, ch chan *cdcpb.ChangeDataEvent, wg *sync.WaitGroup) (grpcServer *grpc.Server, addr string) {
+	lc := &net.ListenConfig{}
+	lis, err := lc.Listen(ctx, "tcp", "127.0.0.1:0")
 	c.Assert(err, check.IsNil)
-	grpcServer := grpc.NewServer()
+	addr = lis.Addr().String()
+	grpcServer = grpc.NewServer()
 	mockService := &mockChangeDataService{c: c, ch: ch}
 	cdcpb.RegisterChangeDataServer(grpcServer, mockService)
 	wg.Add(1)
@@ -103,7 +104,7 @@ func newMockService(c *check.C, port int, ch chan *cdcpb.ChangeDataEvent, wg *sy
 		c.Assert(err, check.IsNil)
 		wg.Done()
 	}()
-	return grpcServer
+	return
 }
 
 type mockPDClient struct {
@@ -124,9 +125,11 @@ func (m *mockPDClient) GetStore(ctx context.Context, storeID uint64) (*metapb.St
 
 // Use etcdSuite to workaround the race. See comments of `TestConnArray`.
 func (s *etcdSuite) TestConnectOfflineTiKV(c *check.C) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
 	wg := &sync.WaitGroup{}
 	ch2 := make(chan *cdcpb.ChangeDataEvent, 10)
-	server2 := newMockService(c, 23376, ch2, wg)
+	server2, addr := newMockService(ctx, c, ch2, wg)
 	defer func() {
 		close(ch2)
 		server2.Stop()
@@ -141,16 +144,14 @@ func (s *etcdSuite) TestConnectOfflineTiKV(c *check.C) {
 	kvStorage, err := tikv.NewTestTiKVStore(rpcClient, pdClient, nil, nil, 0)
 	c.Assert(err, check.IsNil)
 
-	cluster.AddStore(1, "localhost:23375")
-	cluster.AddStore(2, "localhost:23376")
+	cluster.AddStore(1, "localhost:1")
+	cluster.AddStore(2, addr)
 	cluster.Bootstrap(3, []uint64{1, 2}, []uint64{4, 5}, 4)
 
 	lockresolver := txnutil.NewLockerResolver(kvStorage.(tikv.Storage))
 	isPullInit := &mockPullerInit{}
 	cdcClient, err := NewCDCClient(context.Background(), pdClient, kvStorage.(tikv.Storage), &security.Credential{})
 	c.Assert(err, check.IsNil)
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
 	eventCh := make(chan *model.RegionFeedEvent, 10)
 	wg.Add(1)
 	go func() {
@@ -199,6 +200,77 @@ func (s *etcdSuite) TestConnectOfflineTiKV(c *check.C) {
 	cancel()
 }
 
+func (s *etcdSuite) TestRecvLargeMessageSize(c *check.C) {
+	ctx, cancel := context.WithCancel(context.Background())
+	wg := &sync.WaitGroup{}
+	ch2 := make(chan *cdcpb.ChangeDataEvent, 10)
+	server2, addr := newMockService(ctx, c, ch2, wg)
+	defer func() {
+		close(ch2)
+		server2.Stop()
+		wg.Wait()
+	}()
+	// Cancel first, and then close the server.
+	defer cancel()
+
+	cluster := mocktikv.NewCluster()
+	mvccStore := mocktikv.MustNewMVCCStore()
+	rpcClient, pdClient, err := mocktikv.NewTiKVAndPDClient(cluster, mvccStore, "")
+	c.Assert(err, check.IsNil)
+	pdClient = &mockPDClient{Client: pdClient, version: util.MinTiKVVersion.String()}
+	kvStorage, err := tikv.NewTestTiKVStore(rpcClient, pdClient, nil, nil, 0)
+	c.Assert(err, check.IsNil)
+
+	cluster.AddStore(2, addr)
+	cluster.Bootstrap(3, []uint64{2}, []uint64{4}, 4)
+
+	lockresolver := txnutil.NewLockerResolver(kvStorage.(tikv.Storage))
+	isPullInit := &mockPullerInit{}
+	cdcClient, err := NewCDCClient(ctx, pdClient, kvStorage.(tikv.Storage), &security.Credential{})
+	c.Assert(err, check.IsNil)
+	eventCh := make(chan *model.RegionFeedEvent, 10)
+	wg.Add(1)
+	go func() {
+		err := cdcClient.EventFeed(ctx, regionspan.ComparableSpan{Start: []byte("a"), End: []byte("b")}, 1, false, lockresolver, isPullInit, eventCh)
+		c.Assert(errors.Cause(err), check.Equals, context.Canceled)
+		wg.Done()
+	}()
+
+	var event *model.RegionFeedEvent
+	select {
+	case event = <-eventCh:
+	case <-time.After(time.Second):
+		c.Fatalf("recving message takes too long")
+	}
+	c.Assert(event, check.NotNil)
+
+	largeValSize := 128*1024*1024 + 1 // 128MB + 1
+	largeMsg := &cdcpb.ChangeDataEvent{Events: []*cdcpb.Event{
+		{
+			RegionId: 3,
+			Event: &cdcpb.Event_Entries_{
+				Entries: &cdcpb.Event_Entries{
+					Entries: []*cdcpb.Event_Row{{
+						Type:     cdcpb.Event_COMMITTED,
+						OpType:   cdcpb.Event_Row_PUT,
+						Key:      []byte("a"),
+						Value:    make([]byte, largeValSize),
+						CommitTs: 2, // ResolvedTs = 1
+					}},
+				},
+			},
+		},
+	}}
+	ch2 <- largeMsg
+	select {
+	case event = <-eventCh:
+	case <-time.After(30 * time.Second): // Send 128MB object may costs lots of time.
+		c.Fatalf("recving message takes too long")
+	}
+	c.Assert(len(event.Val.Value), check.Equals, largeValSize)
+	cancel()
+}
+
 // TODO enable the test
 func (s *etcdSuite) TodoTestIncompatibleTiKV(c *check.C) {
 	cluster := mocktikv.NewCluster()
diff --git a/go.mod b/go.mod
index c45428de3f1..6e5a8b53585 100644
--- a/go.mod
+++ b/go.mod
@@ -27,7 +27,7 @@ require (
 	github.com/pingcap/check v0.0.0-20200212061837-5e12011dc712
 	github.com/pingcap/errors v0.11.5-0.20200902104258-eba4f1d8f6de
 	github.com/pingcap/failpoint v0.0.0-20200702092429-9f69995143ce
-	github.com/pingcap/kvproto v0.0.0-20200818080353-7aaed8998596
+	github.com/pingcap/kvproto v0.0.0-20200909045102-2ac90648531b
 	github.com/pingcap/log v0.0.0-20200828042413-fce0951f1463
 	github.com/pingcap/parser v0.0.0-20200911054040-258297116c4b
 	github.com/pingcap/tidb v1.1.0-beta.0.20200911063238-51d365fc45fd
diff --git a/go.sum b/go.sum
index 5400fbb71c8..c0ab7629289 100644
--- a/go.sum
+++ b/go.sum
@@ -482,6 +482,8 @@ github.com/pingcap/kvproto v0.0.0-20200518112156-d4aeb467de29/go.mod h1:IOdRDPLy
 github.com/pingcap/kvproto v0.0.0-20200706115936-1e0910aabe6c/go.mod h1:IOdRDPLyda8GX2hE/jO7gqaCV/PNFh8BZQCQZXfIOqI=
 github.com/pingcap/kvproto v0.0.0-20200818080353-7aaed8998596 h1:1cRjX7+yHQiE4pV/xwB8XcbZXV9sHshWMNTd5I6SS2o=
 github.com/pingcap/kvproto v0.0.0-20200818080353-7aaed8998596/go.mod h1:IOdRDPLyda8GX2hE/jO7gqaCV/PNFh8BZQCQZXfIOqI=
+github.com/pingcap/kvproto v0.0.0-20200909045102-2ac90648531b h1:pqOXTOat/yDzc/THrkXx2YgAFfQenEvmn6ub6iEQFfo=
+github.com/pingcap/kvproto v0.0.0-20200909045102-2ac90648531b/go.mod h1:IOdRDPLyda8GX2hE/jO7gqaCV/PNFh8BZQCQZXfIOqI=
 github.com/pingcap/log v0.0.0-20191012051959-b742a5d432e9/go.mod h1:4rbK1p9ILyIfb6hU7OG2CiWSqMXnp3JMbiaVJ6mvoY8=
 github.com/pingcap/log v0.0.0-20200117041106-d28c14d3b1cd/go.mod h1:4rbK1p9ILyIfb6hU7OG2CiWSqMXnp3JMbiaVJ6mvoY8=
 github.com/pingcap/log v0.0.0-20200511115504-543df19646ad h1:SveG82rmu/GFxYanffxsSF503SiQV+2JLnWEiGiF+Tc=