diff --git a/src/db.cc b/src/db.cc
index 02c9a8def..26decaa26 100644
--- a/src/db.cc
+++ b/src/db.cc
@@ -54,8 +54,9 @@ void DB::DoBgSave(const std::string& path, int i) {
 }
 
 void DB::CreateCheckpoint(const std::string& path) {
-  if (0 != pstd::CreatePath(path + '/' + std::to_string(db_index_))) {
-    WARN("Create dir {} fail !", path + '/' + std::to_string(db_index_));
+  auto tmp_path = path + '/' + std::to_string(db_index_);
+  if (0 != pstd::CreatePath(tmp_path)) {
+    WARN("Create dir {} fail !", tmp_path);
     return;
   }
   checkpoint_manager_->CreateCheckpoint(path);
diff --git a/src/praft/praft.cc b/src/praft/praft.cc
index 3fd14fa3d..85ee1c80e 100644
--- a/src/praft/praft.cc
+++ b/src/praft/praft.cc
@@ -372,12 +372,13 @@ void PRaft::AppendLog(const Binlog& log, std::promise<rocksdb::Status>&& promise
   node_->apply(task);
 }
 
-void PRaft::add_all_files(const std::filesystem::path& dir, braft::SnapshotWriter* writer, const std::string& path) {
+void PRaft::AddAllFiles(const std::filesystem::path& dir, braft::SnapshotWriter* writer, const std::string& path) {
+  assert(writer);
   for (const auto& entry : std::filesystem::directory_iterator(dir)) {
     if (entry.is_directory()) {
       if (entry.path() != "." && entry.path() != "..") {
         INFO("dir_path = {}", entry.path().string());
-        add_all_files(entry.path(), writer, path);
+        AddAllFiles(entry.path(), writer, path);
       }
     } else {
       INFO("file_path = {}", std::filesystem::relative(entry.path(), path).string());
@@ -388,9 +389,9 @@ void PRaft::add_all_files(const std::filesystem::path& dir, braft::SnapshotWrite
   }
 }
 
-void PRaft::recursive_copy(const std::filesystem::path& source, const std::filesystem::path& destination) {
+void PRaft::RecursiveCopy(const std::filesystem::path& source, const std::filesystem::path& destination) {
   if (std::filesystem::is_regular_file(source)) {
-    if (source.filename() == "__raft_snapshot_meta") {
+    if (source.filename() == PBRAFT_SNAPSHOT_META_FILE) {
       return;
     } else if (source.extension() == ".sst") {
       // Create a hard link
@@ -407,7 +408,7 @@ void PRaft::recursive_copy(const std::filesystem::path& source, const std::files
     }
 
     for (const auto& entry : std::filesystem::directory_iterator(source)) {
-      recursive_copy(entry.path(), destination / entry.path().filename());
+      RecursiveCopy(entry.path(), destination / entry.path().filename());
     }
   }
 }
@@ -453,7 +454,7 @@ void PRaft::on_snapshot_save(braft::SnapshotWriter* writer, braft::Closure* done
   PSTORE.DoSomeThingSpecificDB(tasks);
   PSTORE.WaitForCheckpointDone();
   auto writer_path = writer->get_path();
-  add_all_files(writer_path, writer, writer_path);
+  AddAllFiles(writer_path, writer, writer_path);
 }
 
 int PRaft::on_snapshot_load(braft::SnapshotReader* reader) {
@@ -466,7 +467,7 @@ int PRaft::on_snapshot_load(braft::SnapshotReader* reader) {
     pstd::DeleteDirIfExist(sub_path);
   }
   db_path.pop_back();
-  recursive_copy(reader_path, db_path);
+  RecursiveCopy(reader_path, db_path);
   PSTORE.Init();
   return 0;
 }
diff --git a/src/praft/praft.h b/src/praft/praft.h
index 1670b2ccf..ff9abf868 100644
--- a/src/praft/praft.h
+++ b/src/praft/praft.h
@@ -20,6 +20,7 @@
 namespace pikiwidb {
 
 #define RAFT_DBID_LEN 32
+#define PBRAFT_SNAPSHOT_META_FILE "__raft_snapshot_meta"
 
 #define PRAFT PRaft::Instance()
 
@@ -139,9 +140,9 @@ class PRaft : public braft::StateMachine {
   void on_start_following(const ::braft::LeaderChangeContext& ctx) override;
 
  private:
-  void add_all_files(const std::filesystem::path& dir, braft::SnapshotWriter* writer, const std::string& path);
+  void AddAllFiles(const std::filesystem::path& dir, braft::SnapshotWriter* writer, const std::string& path);
 
-  void recursive_copy(const std::filesystem::path& source, const std::filesystem::path& destination);
+  void RecursiveCopy(const std::filesystem::path& source, const std::filesystem::path& destination);
 
  private:
   std::unique_ptr<brpc::Server> server_{nullptr};  // brpc