diff --git a/modules/comment/dao/comment.go b/modules/comment/dao/comment.go
index edd8657..61cf834 100644
--- a/modules/comment/dao/comment.go
+++ b/modules/comment/dao/comment.go
@@ -3,7 +3,6 @@ package dao
 import (
 	"context"
 	"errors"
-	"fmt"
 	"time"
 
 	"github.com/NTHU-LSALAB/NTHU-Distributed-System/modules/comment/pb"
@@ -42,8 +41,9 @@ var (
 	ErrCommentNotFound = errors.New("comment not found")
 )
 
+// key format: "listComment:{videoID}:{limit}:{offset}"
 func listCommentKey(videoID string, limit, offset int) string {
-	return fmt.Sprintf("listComment:%s:%d:%d", videoID, limit, offset)
+	// Redis TODO
 }
 
 func NewFakeComment(videoID string) *Comment {
diff --git a/modules/comment/dao/comment_redis.go b/modules/comment/dao/comment_redis.go
index 413bb92..670a50f 100644
--- a/modules/comment/dao/comment_redis.go
+++ b/modules/comment/dao/comment_redis.go
@@ -22,46 +22,35 @@ const (
 	commentDAORedisCacheDuration = 3 * time.Minute
 )
 
+// create redisCommentDAO by cache and baseDAO
 func NewRedisCommentDAO(client *rediskit.RedisClient, baseDAO CommentDAO) *redisCommentDAO {
-	return &redisCommentDAO{
-		cache: cache.New(&cache.Options{
-			Redis:      client,
-			LocalCache: cache.NewTinyLFU(commentDAOLocalCacheSize, commentDAOLocalCacheDuration),
-		}),
-		baseDAO: baseDAO,
-	}
+	// Redis TODO
 }
 
+// List all the comments related to the videoID
+// Notice that all the comments will be stored as a single value in the cache
+// The key is generated by listCommentKey function in comment.go
+// The implementation should handle both cache miss and cache hit scenarios
 func (dao *redisCommentDAO) ListByVideoID(ctx context.Context, videoID string, limit, offset int) ([]*Comment, error) {
-	var comment []*Comment
-
-	if err := dao.cache.Once(&cache.Item{
-		Key:   listCommentKey(videoID, limit, offset),
-		Value: &comment,
-		TTL:   commentDAORedisCacheDuration,
-		Do: func(*cache.Item) (interface{}, error) {
-			return dao.baseDAO.ListByVideoID(ctx, videoID, limit, offset)
-		},
-	}); err != nil {
-		return nil, err
-	}
-	return comment, nil
+	// Redis TODO
 }
 
-// The following operations are not cachable, just pass down to baseDAO
-
+// The operation are not cacheable, just pass down to baseDAO
 func (dao *redisCommentDAO) Create(ctx context.Context, comment *Comment) (uuid.UUID, error) {
-	return dao.baseDAO.Create(ctx, comment)
+	// Redis TODO
 }
 
+// The following operations are not cacheable, just pass down to baseDAO
 func (dao *redisCommentDAO) Update(ctx context.Context, comment *Comment) error {
-	return dao.baseDAO.Update(ctx, comment)
+	// Redis TODO
 }
 
+// The following operations are not cacheable, just pass down to baseDAO
 func (dao *redisCommentDAO) Delete(ctx context.Context, id uuid.UUID) error {
-	return dao.baseDAO.Delete(ctx, id)
+	// Redis TODO
 }
 
+// The following operations are not cacheable, just pass down to baseDAO
 func (dao *redisCommentDAO) DeleteByVideoID(ctx context.Context, videoID string) error {
-	return dao.baseDAO.DeleteByVideoID(ctx, videoID)
+	// Redis TODO
 }