diff --git a/fileserver/fileop.go b/fileserver/fileop.go
index f3c7c7a..8083a18 100644
--- a/fileserver/fileop.go
+++ b/fileserver/fileop.go
@@ -299,6 +299,14 @@ func doFile(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, fileID
 		}
 	}
 
+	if operation != "view" {
+		oper := "web-file-download"
+		if operation == "download-link" {
+			oper = "link-file-download"
+		}
+		sendStatisticMsg(repo.StoreID, user, oper, file.FileSize)
+	}
+
 	return nil
 }
 
@@ -446,6 +454,12 @@ func doFileRange(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, f
 		}
 	}
 
+	oper := "web-file-download"
+	if operation == "download-link" {
+		oper = "link-file-download"
+	}
+	sendStatisticMsg(repo.StoreID, user, oper, file.FileSize)
+
 	return nil
 }
 
@@ -632,6 +646,8 @@ func doBlock(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, fileI
 		log.Printf("fatild to write block %s to response: %v", blkID, err)
 	}
 
+	sendStatisticMsg(repo.StoreID, user, "web-file-download", uint64(size))
+
 	return nil
 }
 
@@ -1670,7 +1686,7 @@ func genCommitNeedRetry(repo *repomgr.Repo, base *commitmgr.Commit, commit *comm
 		mergedCommit = commit
 	}
 
-	err = updateBranch(repoID, mergedCommit.CommitID, currentHead.CommitID)
+	err = updateBranch(repoID, mergedCommit.CommitID, currentHead.CommitID, commit.CommitID)
 	if err != nil {
 		return true, nil
 	}
@@ -1693,7 +1709,7 @@ func genMergeDesc(repo *repomgr.Repo, mergedRoot, p1Root, p2Root string) string
 	return desc
 }
 
-func updateBranch(repoID, newCommitID, oldCommitID string) error {
+func updateBranch(repoID, newCommitID, oldCommitID, secondParentID string) error {
 	var commitID string
 	name := "master"
 	var sqlStr string
@@ -1730,6 +1746,34 @@ func updateBranch(repoID, newCommitID, oldCommitID string) error {
 
 	trans.Commit()
 
+	if secondParentID != "" {
+		if err := onBranchUpdated(repoID, secondParentID, false); err != nil {
+			return err
+		}
+	}
+
+	if err := onBranchUpdated(repoID, newCommitID, true); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func onBranchUpdated(repoID string, commitID string, updateRepoInfo bool) error {
+	if updateRepoInfo {
+		if err := repomgr.UpdateRepoInfo(repoID, commitID); err != nil {
+			return err
+		}
+	}
+
+	isVirtual, err := repomgr.IsVirtualRepo(repoID)
+	if err != nil {
+		return err
+	}
+	if isVirtual {
+		return nil
+	}
+	publishUpdateEvent(repoID, commitID)
 	return nil
 }
 
diff --git a/fileserver/repomgr/repomgr.go b/fileserver/repomgr/repomgr.go
index 05b67d1..93b0a48 100644
--- a/fileserver/repomgr/repomgr.go
+++ b/fileserver/repomgr/repomgr.go
@@ -427,8 +427,7 @@ func DelUploadTmpFile(repoID, filePath string) error {
 	return nil
 }
 
-// SetRepoCommitToDb updates the table of RepoInfo.
-func SetRepoCommitToDb(repoID, repoName string, updateTime int64, version int, isEncrypted string, lastModifier string) error {
+func setRepoCommitToDb(repoID, repoName string, updateTime int64, version int, isEncrypted string, lastModifier string) error {
 	var exists int
 	var encrypted int
 
@@ -641,3 +640,15 @@ func GetRepoOwner(repoID string) (string, error) {
 
 	return owner, nil
 }
+
+func UpdateRepoInfo(repoID, commitID string) error {
+	head, err := commitmgr.Load(repoID, commitID)
+	if err != nil {
+		err := fmt.Errorf("failed to get commit %s:%s", repoID, commitID)
+		return err
+	}
+
+	setRepoCommitToDb(repoID, head.RepoName, head.Ctime, head.Version, head.Encrypted, head.CreatorName)
+
+	return nil
+}
diff --git a/fileserver/sync_api.go b/fileserver/sync_api.go
index 6c1c521..97ff8ed 100644
--- a/fileserver/sync_api.go
+++ b/fileserver/sync_api.go
@@ -42,6 +42,7 @@ const (
 	permExpireTime             = 7200
 	virtualRepoExpireTime      = 7200
 	syncAPICleaningIntervalSec = 300
+	maxObjectPackSize          = 1 << 20 // 1MB
 )
 
 var (
@@ -473,6 +474,7 @@ func packFSCB(rsp http.ResponseWriter, r *http.Request) *appError {
 		return &appError{nil, err.Error(), http.StatusBadRequest}
 	}
 
+	var totalSize int
 	var data bytes.Buffer
 	for i := 0; i < len(fsIDList); i++ {
 		if !isObjectIDValid(fsIDList[i]) {
@@ -489,6 +491,11 @@ func packFSCB(rsp http.ResponseWriter, r *http.Request) *appError {
 		binary.BigEndian.PutUint32(tmpLen, uint32(tmp.Len()))
 		data.Write(tmpLen)
 		data.Write(tmp.Bytes())
+
+		totalSize += tmp.Len()
+		if totalSize >= maxObjectPackSize {
+			break
+		}
 	}
 
 	rsp.Header().Set("Content-Length", strconv.Itoa(data.Len()))
@@ -1128,6 +1135,13 @@ func publishRepoEvent(rData *repoEventData) {
 	}
 }
 
+func publishUpdateEvent(repoID string, commitID string) {
+	buf := fmt.Sprintf("repo-update\t%s\t%s", repoID, commitID)
+	if _, err := rpcclient.Call("publish_event", seafileServerChannelEvent, buf); err != nil {
+		log.Printf("Failed to publish event: %v", err)
+	}
+}
+
 func removeSyncAPIExpireCache() {
 	deleteTokens := func(key interface{}, value interface{}) bool {
 		if info, ok := value.(*tokenInfo); ok {
diff --git a/fileserver/virtual_repo.go b/fileserver/virtual_repo.go
index e4b54ff..4a7c4c2 100644
--- a/fileserver/virtual_repo.go
+++ b/fileserver/virtual_repo.go
@@ -321,24 +321,12 @@ func editRepoNeedRetry(repoID, name, desc, user string) (bool, error) {
 		return false, err
 	}
 
-	err = updateBranch(repoID, commit.CommitID, parent.CommitID)
+	err = updateBranch(repoID, commit.CommitID, parent.CommitID, "")
 	if err != nil {
 		return true, nil
 	}
 
-	updateRepoInfo(repoID, commit.CommitID)
+	repomgr.UpdateRepoInfo(repoID, commit.CommitID)
 
 	return true, nil
 }
-
-func updateRepoInfo(repoID, commitID string) error {
-	head, err := commitmgr.Load(repoID, commitID)
-	if err != nil {
-		err := fmt.Errorf("failed to get commit %s:%s", repoID, commitID)
-		return err
-	}
-
-	repomgr.SetRepoCommitToDb(repoID, head.RepoName, head.Ctime, head.Version, head.Encrypted, head.CreatorName)
-
-	return nil
-}