diff --git a/util/safe_handler.h b/util/safe_handler.h
index 673c8348e05979730991fa0112830839288429f7..3cbce4996661f99a35a7b2a5231c9547182ea7ce 100644
--- a/util/safe_handler.h
+++ b/util/safe_handler.h
@@ -17,7 +17,7 @@
 #include <mutex>
 #include <iostream>
 #include <unistd.h>
-#include <unordered_set>
+#include <set>
 
 template <typename Key>
 class SafeHandler {
@@ -50,7 +50,7 @@ public:
 private:
     std::mutex _mutex;
     std::mutex _smutex;
-    std::unordered_set<Key> _set;
+    std::set<Key> _set;
 
     void insert(const Key& key)
     {