chore: Add vlog printings every time we switch global state

Should help debugging #1204

Signed-off-by: Roman Gershman <roman@dragonflydb.io>

src/server/common.cc

@@ -320,3 +320,22 @@ GenericError Context::ReportErrorInternal(GenericError&& err) {
 }
 
 }  // namespace dfly
+
+namespace std {
+
+ostream& operator<<(ostream& os, const dfly::GlobalState gs) {
+  switch (gs) {
+    case dfly::GlobalState::ACTIVE:
+      return os << "ACTIVE";
+    case dfly::GlobalState::LOADING:
+      return os << "LOADING";
+    case dfly::GlobalState::SAVING:
+      return os << "SAVING";
+    case dfly::GlobalState::SHUTTING_DOWN:
+      return os << "SHUTTING DOWN";
+  }
+
+  return os;
+}
+
+}  // namespace std

src/server/common.h

@@ -343,3 +343,9 @@ inline uint32_t MemberTimeSeconds(uint64_t now_ms) {
 }
 
 }  // namespace dfly
+
+namespace std {
+
+ostream& operator<<(ostream& os, const dfly::GlobalState gs);
+
+}  // namespace std

src/server/main_service.cc

@@ -1739,6 +1739,9 @@ GlobalState Service::SwitchState(GlobalState from, GlobalState to) {
   lock_guard lk(mu_);
   if (global_state_ != from)
     return global_state_;
+
+  VLOG(1) << "Switching state from " << global_state_ << " to " << to;
+
   global_state_ = to;
 
   pp_.Await([&](ProactorBase*) { ServerState::tlocal()->set_gstate(to); });

src/server/server_family.cc

@@ -563,16 +563,6 @@ Future<std::error_code> ServerFamily::Load(const std::string& load_path) {
     return {};
   }
 
-#if 0
-  auto& pool = service_.proactor_pool();
-  // Deliberately run on all I/O threads to update the state for non-shard threads as well.
-  pool.Await([&](ProactorBase*) {
-    // TODO: There can be a bug where status is different.
-    CHECK(ServerState::tlocal()->gstate() == GlobalState::IDLE);
-    ServerState::tlocal()->set_gstate(GlobalState::LOADING);
-  });
-#endif
-
   auto& pool = service_.proactor_pool();
 
   vector<Fiber> load_fibers;