diff --git a/src/Interpreters/ClusterDiscovery.cpp b/src/Interpreters/ClusterDiscovery.cpp
index d32017873b9..69dcc8a79fe 100644
--- a/src/Interpreters/ClusterDiscovery.cpp
+++ b/src/Interpreters/ClusterDiscovery.cpp
@@ -60,20 +60,17 @@ public:
 
     void set(const T & key)
     {
-        setFlag(key, true);
-        cv.notify_one();
-    }
-
-    /// `need_update` expected to be value from `flags` corresponding to some key
-    void set(std::atomic_bool & need_update)
-    {
+        auto it = flags.find(key);
+        if (it == flags.end())
+            throw DB::Exception(ErrorCodes::LOGICAL_ERROR, "Unknown value '{}'", key);
+        it->second = true;
         any_need_update = true;
-        need_update = true;
         cv.notify_one();
     }
 
     /// waits unit at least one flag is set
     /// caller should handle all set flags (or set it again manually)
+    /// note: keys of returen map should not be changed!
     std::unordered_map<T, std::atomic_bool> & wait(std::atomic_bool & finished, std::chrono::milliseconds timeout)
     {
         std::unique_lock<std::mutex> lk(mu);
@@ -89,16 +86,6 @@ public:
     void notify() { cv.notify_one(); }
 
 private:
-    void setFlag(const T & key, bool value)
-    {
-        any_need_update = any_need_update || value;
-
-        auto it = flags.find(key);
-        if (it == flags.end())
-            throw DB::Exception(ErrorCodes::LOGICAL_ERROR, "Unknown value '{}'", key);
-        it->second = value;
-    }
-
     std::condition_variable cv;
     std::mutex mu;
 
@@ -395,7 +382,8 @@ bool ClusterDiscovery::runMainThread()
             }
             else
             {
-                clusters_to_update->set(need_update);
+                /// no need to trigger convar, will retry after timeout in `wait`
+                need_update = true;
                 LOG_WARNING(log, "Cluster '{}' wasn't updated, will retry", cluster_name);
             }
         }