diff --git a/cpp/CHANGELOG.md b/cpp/CHANGELOG.md
index a8a5af195f32f1017e652a75a005cd0577baa1e5..85c488ebdee4ca6168cb309d4bc632cb2e8223c1 100644
--- a/cpp/CHANGELOG.md
+++ b/cpp/CHANGELOG.md
@@ -5,6 +5,7 @@ Please mark all change in change log and use the ticket from JIRA.
 # MegaSearch 0.3.0 (TBD)
 
 ## Bug
+- MS-80 - Fix server hang issue
 
 ## Improvement
 - MS-82 - Update server startup welcome message
diff --git a/cpp/src/db/scheduler/IndexLoaderQueue.cpp b/cpp/src/db/scheduler/IndexLoaderQueue.cpp
index 7d7ae07374c3eb52216cde0e35e7e3f1aeeff536..2522815520ccc512f74d86118eccc54f7fe0da95 100644
--- a/cpp/src/db/scheduler/IndexLoaderQueue.cpp
+++ b/cpp/src/db/scheduler/IndexLoaderQueue.cpp
@@ -13,12 +13,6 @@ namespace zilliz {
 namespace milvus {
 namespace engine {
 
-IndexLoaderQueue&
-IndexLoaderQueue::GetInstance() {
-    static IndexLoaderQueue instance;
-    return instance;
-}
-
 void
 IndexLoaderQueue::Put(const SearchContextPtr &search_context) {
     std::unique_lock <std::mutex> lock(mtx);
@@ -26,6 +20,7 @@ IndexLoaderQueue::Put(const SearchContextPtr &search_context) {
 
     if(search_context == nullptr) {
         queue_.push_back(nullptr);
+        empty_.notify_all();
         return;
     }
 
diff --git a/cpp/src/db/scheduler/IndexLoaderQueue.h b/cpp/src/db/scheduler/IndexLoaderQueue.h
index 150dde84841e212de69fd65f77b693098eec5dea..4f6dcfcd67c50bf4c2bdabc5de14925e5d4eb65e 100644
--- a/cpp/src/db/scheduler/IndexLoaderQueue.h
+++ b/cpp/src/db/scheduler/IndexLoaderQueue.h
@@ -26,18 +26,15 @@ public:
 using IndexLoaderContextPtr = std::shared_ptr<IndexLoaderContext>;
 
 class IndexLoaderQueue {
-private:
+public:
     IndexLoaderQueue() : mtx(), full_(), empty_() {}
 
     IndexLoaderQueue(const IndexLoaderQueue &rhs) = delete;
 
     IndexLoaderQueue &operator=(const IndexLoaderQueue &rhs) = delete;
 
-public:
     using LoaderQueue = std::list<IndexLoaderContextPtr>;
 
-    static IndexLoaderQueue& GetInstance();
-
     void Put(const SearchContextPtr &search_context);
 
     IndexLoaderContextPtr Take();
diff --git a/cpp/src/db/scheduler/SearchScheduler.cpp b/cpp/src/db/scheduler/SearchScheduler.cpp
index 2235ee9df3bf08c7ecdf0c5542eedda6406df619..756abea4cdf9ef4e09956e301920c1839dd56f97 100644
--- a/cpp/src/db/scheduler/SearchScheduler.cpp
+++ b/cpp/src/db/scheduler/SearchScheduler.cpp
@@ -55,8 +55,7 @@ void CollectDurationMetrics(int index_type, double total_time) {
 }
 
 SearchScheduler::SearchScheduler()
-    : thread_pool_(2),
-      stopped_(true) {
+    : stopped_(true) {
     Start();
 }
 
@@ -75,8 +74,13 @@ SearchScheduler::Start() {
         return true;
     }
 
-    thread_pool_.enqueue(&SearchScheduler::IndexLoadWorker, this);
-    thread_pool_.enqueue(&SearchScheduler::SearchWorker, this);
+    stopped_ = false;
+
+    search_queue_.SetCapacity(2);
+
+    index_load_thread_ = std::make_shared<std::thread>(&SearchScheduler::IndexLoadWorker, this);
+    search_thread_  = std::make_shared<std::thread>(&SearchScheduler::SearchWorker, this);
+
     return true;
 }
 
@@ -86,29 +90,34 @@ SearchScheduler::Stop() {
         return true;
     }
 
-    IndexLoaderQueue& index_queue = IndexLoaderQueue::GetInstance();
-    index_queue.Put(nullptr);
+    if(index_load_thread_) {
+        index_load_queue_.Put(nullptr);
+        index_load_thread_->join();
+        index_load_thread_ = nullptr;
+    }
+
+    if(search_thread_) {
+        search_queue_.Put(nullptr);
+        search_thread_->join();
+        search_thread_ = nullptr;
+    }
 
-    SearchTaskQueue& search_queue = SearchTaskQueue::GetInstance();
-    search_queue.Put(nullptr);
+    stopped_ = true;
 
     return true;
 }
 
 bool
 SearchScheduler::ScheduleSearchTask(SearchContextPtr& search_context) {
-    IndexLoaderQueue& index_queue = IndexLoaderQueue::GetInstance();
-    index_queue.Put(search_context);
+    index_load_queue_.Put(search_context);
 
     return true;
 }
 
 bool
 SearchScheduler::IndexLoadWorker() {
-    IndexLoaderQueue& index_queue = IndexLoaderQueue::GetInstance();
-    SearchTaskQueue& search_queue = SearchTaskQueue::GetInstance();
     while(true) {
-        IndexLoaderContextPtr context = index_queue.Take();
+        IndexLoaderContextPtr context = index_load_queue_.Take();
         if(context == nullptr) {
             SERVER_LOG_INFO << "Stop thread for index loading";
             break;//exit
@@ -137,7 +146,7 @@ SearchScheduler::IndexLoadWorker() {
         task_ptr->index_type_ = context->file_->file_type_;
         task_ptr->index_engine_ = index_ptr;
         task_ptr->search_contexts_.swap(context->search_contexts_);
-        search_queue.Put(task_ptr);
+        search_queue_.Put(task_ptr);
     }
 
     return true;
@@ -145,9 +154,8 @@ SearchScheduler::IndexLoadWorker() {
 
 bool
 SearchScheduler::SearchWorker() {
-    SearchTaskQueue& search_queue = SearchTaskQueue::GetInstance();
     while(true) {
-        SearchTaskPtr task_ptr = search_queue.Take();
+        SearchTaskPtr task_ptr = search_queue_.Take();
         if(task_ptr == nullptr) {
             SERVER_LOG_INFO << "Stop thread for searching";
             break;//exit
diff --git a/cpp/src/db/scheduler/SearchScheduler.h b/cpp/src/db/scheduler/SearchScheduler.h
index 8b797908ef1cfd200783af005e134cd9c904d5aa..6e84c43684c6c83913425b72ba726c1f1d74cbf0 100644
--- a/cpp/src/db/scheduler/SearchScheduler.h
+++ b/cpp/src/db/scheduler/SearchScheduler.h
@@ -6,7 +6,8 @@
 #pragma once
 
 #include "SearchContext.h"
-#include "utils/ThreadPool.h"
+#include "IndexLoaderQueue.h"
+#include "SearchTaskQueue.h"
 
 namespace zilliz {
 namespace milvus {
@@ -30,7 +31,12 @@ private:
     bool SearchWorker();
 
 private:
-    server::ThreadPool thread_pool_;
+    std::shared_ptr<std::thread> index_load_thread_;
+    std::shared_ptr<std::thread> search_thread_;
+
+    IndexLoaderQueue index_load_queue_;
+    SearchTaskQueue search_queue_;
+
     bool stopped_ = true;
 };
 
diff --git a/cpp/src/db/scheduler/SearchTaskQueue.cpp b/cpp/src/db/scheduler/SearchTaskQueue.cpp
index f077001f901764bad2cbde967c5a46e50dedb94f..a0ed0834d03a6e5b7993d3dbfa4e43ee03ed3883 100644
--- a/cpp/src/db/scheduler/SearchTaskQueue.cpp
+++ b/cpp/src/db/scheduler/SearchTaskQueue.cpp
@@ -94,18 +94,6 @@ void CalcScore(uint64_t vector_count,
 
 }
 
-
-SearchTaskQueue::SearchTaskQueue() {
-    SetCapacity(4);
-}
-
-
-SearchTaskQueue&
-SearchTaskQueue::GetInstance() {
-    static SearchTaskQueue instance;
-    return instance;
-}
-
 bool SearchTask::DoSearch() {
     if(index_engine_ == nullptr) {
         return false;
diff --git a/cpp/src/db/scheduler/SearchTaskQueue.h b/cpp/src/db/scheduler/SearchTaskQueue.h
index 7231870bd34a7d9d0eddbf3fd7da6c441fad2e41..e5841cd1d5a1a2f55872a10c2ee46c3758548805 100644
--- a/cpp/src/db/scheduler/SearchTaskQueue.h
+++ b/cpp/src/db/scheduler/SearchTaskQueue.h
@@ -27,21 +27,7 @@ public:
 };
 
 using SearchTaskPtr = std::shared_ptr<SearchTask>;
-
-class SearchTaskQueue : public server::BlockingQueue<SearchTaskPtr> {
-private:
-    SearchTaskQueue();
-
-    SearchTaskQueue(const SearchTaskQueue &rhs) = delete;
-
-    SearchTaskQueue &operator=(const SearchTaskQueue &rhs) = delete;
-
-public:
-    static SearchTaskQueue& GetInstance();
-
-private:
-
-};
+using SearchTaskQueue = server::BlockingQueue<SearchTaskPtr>;
 
 
 }