Fsync at server shutdown

src/Coordination/Changelog.cpp

@@ -467,6 +467,17 @@ void Changelog::flush()
     current_writer->flush();
 }
 
-Changelog::~Changelog() = default;
+Changelog::~Changelog()
+{
+    try
+    {
+        if (current_writer)
+            current_writer->flush();
+    }
+    catch (...)
+    {
+        tryLogCurrentException(__PRETTY_FUNCTION__);
+    }
+}
 
 }

src/Coordination/InMemoryStateManager.cpp

@@ -66,6 +66,11 @@ void InMemoryStateManager::loadLogStore(size_t start_log_index)
     log_store->init(start_log_index);
 }
 
+void InMemoryStateManager::flushLogStore()
+{
+    log_store->flush();
+}
+
 void InMemoryStateManager::save_config(const nuraft::cluster_config & config)
 {
     // Just keep in memory in this example.

src/Coordination/InMemoryStateManager.h

@@ -27,6 +27,8 @@ public:
 
     void loadLogStore(size_t start_log_index);
 
+    void flushLogStore();
+
     nuraft::ptr<nuraft::cluster_config> load_config() override { return cluster_config; }
 
     void save_config(const nuraft::cluster_config & config) override;

src/Coordination/NuKeeperServer.cpp

@@ -67,6 +67,7 @@ void NuKeeperServer::startup()
 void NuKeeperServer::shutdown()
 {
     state_machine->shutdownStorage();
+    state_manager->flushLogStore();
     if (!launcher.shutdown(coordination_settings->shutdown_timeout.totalSeconds()))
         LOG_WARNING(&Poco::Logger::get("NuKeeperServer"), "Failed to shutdown RAFT server in {} seconds", 5);
 }