diff --git a/cpp/src/db/DB.cpp b/cpp/src/db/DB.cpp
index b30f481464..808c87ad1d 100644
--- a/cpp/src/db/DB.cpp
+++ b/cpp/src/db/DB.cpp
@@ -19,7 +19,6 @@ DB::~DB() {}
 
 void DB::Open(const Options& options, DB** dbptr) {
     *dbptr = nullptr;
-    /* *dbptr = new DBImpl<FaissExecutionEngine<IVFIndexTrait>>(options); */
     *dbptr = DBFactory::Build(options);
     return;
 }
diff --git a/cpp/src/db/DBImpl.cpp b/cpp/src/db/DBImpl.cpp
index 80f433e98b..79266ddca0 100644
--- a/cpp/src/db/DBImpl.cpp
+++ b/cpp/src/db/DBImpl.cpp
@@ -176,8 +176,7 @@ Status DBImpl<EngineT>::search(const std::string& group_id, size_t k, size_t nq,
 
 template<typename EngineT>
 void DBImpl<EngineT>::start_timer_task(int interval_) {
-    std::thread bg_task(&DBImpl<EngineT>::background_timer_task, this, interval_);
-    bg_task.detach();
+    bg_timer_thread_ = std::thread(&DBImpl<EngineT>::background_timer_task, this, interval_);
 }
 
 template<typename EngineT>
@@ -403,6 +402,7 @@ DBImpl<EngineT>::~DBImpl() {
             bg_build_index_finish_signal_.wait(lock);
         }
     }
+    bg_timer_thread_.join();
     std::vector<std::string> ids;
     _pMemMgr->serialize(ids);
     _env->Stop();
diff --git a/cpp/src/db/DBImpl.h b/cpp/src/db/DBImpl.h
index 8896a1d48b..d2aed0af1d 100644
--- a/cpp/src/db/DBImpl.h
+++ b/cpp/src/db/DBImpl.h
@@ -87,6 +87,8 @@ private:
     bool bg_build_index_started_;
     std::condition_variable bg_build_index_finish_signal_;
 
+    std::thread bg_timer_thread_;
+
     MetaPtr _pMeta;
     MemManagerPtr _pMemMgr;