diff --git a/pkg/common/db/dataver/common.go b/pkg/common/db/dataver/common.go
index c146600fb..c7e4658ab 100644
--- a/pkg/common/db/dataver/common.go
+++ b/pkg/common/db/dataver/common.go
@@ -24,6 +24,23 @@ type WriteLog struct {
 	LogLen     int       `bson:"log_len"`
 }
 
+func (w *WriteLog) Full() bool {
+	if w.Version == 0 {
+		return true
+	}
+	return len(w.Logs) != w.LogLen
+}
+
+func (w *WriteLog) DeleteEId() []string {
+	var eIds []string
+	for _, l := range w.Logs {
+		if l.Deleted {
+			eIds = append(eIds, l.EID)
+		}
+	}
+	return eIds
+}
+
 type Elem struct {
 	EID        string    `bson:"e_id"`
 	Deleted    bool      `bson:"deleted"`
@@ -33,7 +50,7 @@ type Elem struct {
 
 type DataLog interface {
 	WriteLog(ctx context.Context, dId string, eIds []string, deleted bool) error
-	FindChangeLog(ctx context.Context, did string, version uint, limit int) (*WriteLog, error)
+	FindChangeLog(ctx context.Context, dId string, version uint, limit int) (*WriteLog, error)
 	DeleteAfterUnchangedLog(ctx context.Context, deadline time.Time) error
 }
 
@@ -173,11 +190,11 @@ func (l *logModel) writeLogBatch(ctx context.Context, dId string, eIds []string,
 	return mongoutil.UpdateMany(ctx, l.coll, filter, pipeline)
 }
 
-func (l *logModel) FindChangeLog(ctx context.Context, did string, version uint, limit int) (*WriteLog, error) {
+func (l *logModel) FindChangeLog(ctx context.Context, dId string, version uint, limit int) (*WriteLog, error) {
 	pipeline := []bson.M{
 		{
 			"$match": bson.M{
-				"d_id": did,
+				"d_id": dId,
 			},
 		},
 		{
diff --git a/pkg/common/db/dataver/result.go b/pkg/common/db/dataver/result.go
new file mode 100644
index 000000000..b6e6d22b4
--- /dev/null
+++ b/pkg/common/db/dataver/result.go
@@ -0,0 +1,32 @@
+package dataver
+
+type SyncResult[T any] struct {
+	Version   uint
+	DeleteEID []string
+	Changes   []T
+	Full      bool
+}
+
+func NewSyncResult[T any](wl *WriteLog, find func(eIds []string) ([]T, error)) (*SyncResult[T], error) {
+	var findEIDs []string
+	var res SyncResult[T]
+	if wl.Full() {
+		res.Full = true
+	} else {
+		for _, l := range wl.Logs {
+			if l.Deleted {
+				res.DeleteEID = append(res.DeleteEID, l.EID)
+			} else {
+				findEIDs = append(findEIDs, l.EID)
+			}
+		}
+	}
+	if res.Full || len(findEIDs) > 0 {
+		var err error
+		res.Changes, err = find(findEIDs)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &res, nil
+}
diff --git a/pkg/common/db/mgo/friend.go b/pkg/common/db/mgo/friend.go
index a44244fca..78e74edd3 100644
--- a/pkg/common/db/mgo/friend.go
+++ b/pkg/common/db/mgo/friend.go
@@ -16,6 +16,7 @@ package mgo
 
 import (
 	"context"
+	"errors"
 	"github.com/openimsdk/open-im-server/v3/pkg/common/db/dataver"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/db/table/relation"
@@ -182,6 +183,20 @@ func (f *FriendMgo) UpdateFriends(ctx context.Context, ownerUserID string, frien
 	})
 }
 
+func (f *FriendMgo) IncrSync(ctx context.Context, ownerUserID string, version uint, limit int) (*dataver.SyncResult[*relation.FriendModel], error) {
+	res, err := f.owner.FindChangeLog(ctx, ownerUserID, version, limit)
+	if err != nil {
+		return nil, err
+	}
+	return dataver.NewSyncResult[*relation.FriendModel](res, func(eIds []string) ([]*relation.FriendModel, error) {
+		if len(eIds) == 0 {
+			return nil, errors.New("todo")
+		} else {
+			return f.FindFriends(ctx, ownerUserID, eIds)
+		}
+	})
+}
+
 func Success(fns ...func() error) error {
 	for _, fn := range fns {
 		if err := fn(); err != nil {
diff --git a/pkg/common/listdemo2/common.go b/pkg/common/listdemo2/common.go
index 2267d8630..40419d533 100644
--- a/pkg/common/listdemo2/common.go
+++ b/pkg/common/listdemo2/common.go
@@ -70,54 +70,6 @@ func (l *LogModel) InitIndex(ctx context.Context) error {
 	return err
 }
 
-func (l *LogModel) WriteLog1(ctx context.Context, dId string, eId string, deleted bool) {
-	if err := l.WriteLog(ctx, dId, eId, deleted); err != nil {
-		panic(err)
-	}
-}
-
-func (l *LogModel) WriteLogBatch1(ctx context.Context, dId string, eIds []string, deleted bool) {
-	if err := l.WriteLogBatch(ctx, dId, eIds, deleted); err != nil {
-		panic(err)
-	}
-}
-
-func (l *LogModel) WriteLog(ctx context.Context, dId string, eId string, deleted bool) error {
-	now := time.Now()
-	res, err := l.writeLog(ctx, dId, eId, deleted, now)
-	if err != nil {
-		return err
-	}
-	if res.MatchedCount > 0 {
-		return nil
-	}
-	wl := WriteLog{
-		DID: dId,
-		Logs: []LogElem{
-			{
-				EID:        eId,
-				Deleted:    deleted,
-				Version:    FirstVersion,
-				LastUpdate: now,
-			},
-		},
-		Version:    FirstVersion,
-		Deleted:    DefaultDeleteVersion,
-		LastUpdate: now,
-	}
-	if _, err := l.coll.InsertOne(ctx, &wl); err == nil {
-		return nil
-	} else if !mongo.IsDuplicateKeyError(err) {
-		return err
-	}
-	if res, err := l.writeLog(ctx, dId, eId, deleted, now); err != nil {
-		return err
-	} else if res.ModifiedCount == 0 {
-		return errs.ErrInternalServer.WrapMsg("mongodb return value that should not occur", "coll", l.coll.Name(), "dId", dId, "eId", eId)
-	}
-	return nil
-}
-
 func (l *LogModel) writeLog(ctx context.Context, dId string, eId string, deleted bool, now time.Time) (*mongo.UpdateResult, error) {
 	filter := bson.M{
 		"d_id": dId,
@@ -356,7 +308,7 @@ func (l *LogModel) FindChangeLog(ctx context.Context, did string, version uint,
 		return nil, err
 	}
 	if len(res) == 0 {
-		return nil, ErrNotFound
+		return &WriteLogLen{}, nil
 	}
 	return res[0], nil
 }