disable tso fallback by default

Signed-off-by: Ryan Leung <[email protected]>

server/cluster/cluster.go

@@ -418,8 +418,11 @@ func (c *RaftCluster) checkTSOService() {
 			}
 			c.SetServiceIndependent(constant.TSOServiceName)
 		} else if c.opt.GetMicroServiceConfig().IsTSOFallbackEnabled() {
-			// TSO server is not available, we need to initialize the PD's allocator group and
+			// TSO server is not available.
+			// If TSO fallback is enabled, we need to initialize the PD's allocator group and
 			// let PD provide the timestamp through UnsetServiceIndependent.
+			// Otherwise, we will wait for the TSO service to be available.
+			// In this case, no timestamp will be provided.
 			if !allocator.IsInitialize() {
 				log.Info("initializing the global TSO allocator")
 				if err := allocator.Initialize(0); err != nil {

server/config/config.go

@@ -253,7 +253,7 @@ const (
 	maxCheckRegionSplitInterval     = 100 * time.Millisecond
 
 	defaultEnableSchedulingFallback = true
-	defaultEnableTSOFallback        = true
+	defaultEnableTSOFallback        = false
 )
 
 // Special keys for Labels

server/grpc_service.go

@@ -593,7 +593,7 @@ func (s *GrpcServer) Tso(stream pdpb.PD_TsoServer) error {
 		if s.forwardToTSOService() {
 			if request.GetCount() == 0 {
 				err = errs.ErrGenerateTimestamp.FastGenByArgs("tso count should be positive")
-				return status.Errorf(codes.Unknown, err.Error())
+				return status.Error(codes.Unknown, err.Error())
 			}
 
 			forwardedHost, ok := s.GetServicePrimaryAddr(stream.Context(), constant.TSOServiceName)