Fixed error in ZK library [#CLICKHOUSE-3753]

dbms/src/Common/ZooKeeper/ZooKeeperImpl.cpp

@@ -996,13 +996,14 @@ void ZooKeeper::receiveEvent()
 
 void ZooKeeper::finalize(bool error_send, bool error_receive)
 {
-    std::unique_lock lock(finalize_mutex, std::defer_lock);
-    if (!lock.try_lock())
-        return;
+    {
+        /// Will wait for pushRequest method.
+        std::unique_lock lock(expired_mutex);
 
         if (expired)
             return;
         expired = true;
+    }
 
     active_session_metric_increment.destroy();
 
@@ -1020,6 +1021,7 @@ void ZooKeeper::finalize(bool error_send, bool error_receive)
                 /// This happens for example, when "Cannot push request to queue within operation timeout".
                 tryLogCurrentException(__PRETTY_FUNCTION__);
             }
+
             send_thread.join();
         }
 
@@ -1348,7 +1350,7 @@ void ZooKeeper::pushRequest(RequestInfo && info)
         ///  to avoid forgotten operations in the queue when session is expired.
         /// Invariant: when expired, no new operations will be pushed to the queue in 'pushRequest'
         ///  and the queue will be drained in 'finalize'.
-        std::lock_guard lock(finalize_mutex);
+        std::lock_guard lock(expired_mutex);
 
         if (expired)
             throw Exception("Session expired", ZSESSIONEXPIRED);

dbms/src/Common/ZooKeeper/ZooKeeperImpl.h

@@ -573,7 +573,7 @@ private:
 
     std::atomic<XID> xid {1};
     std::atomic<bool> expired {false};
-    std::mutex finalize_mutex;
+    std::mutex expired_mutex;
 
     using clock = std::chrono::steady_clock;