diff --git a/paddle/fluid/operators/detail/grpc_client.cc b/paddle/fluid/operators/detail/grpc_client.cc
index f8ec39e8c519ab8b40c2fc7fa7ec4dfff4e7060a..d79ba6d291950e1f089eb11713bd1c3e4d154b27 100644
--- a/paddle/fluid/operators/detail/grpc_client.cc
+++ b/paddle/fluid/operators/detail/grpc_client.cc
@@ -72,8 +72,7 @@ void ProcGetResponse(const VarHandle& var_h,
 template <typename T>
 void RequestToByteBuffer(const T& proto, ::grpc::ByteBuffer* result) {
   ::grpc::Slice slice(proto.ByteSizeLong());
-  proto.SerializeWithCachedSizesToArray(
-      const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(slice.begin())));
+  proto.SerializeWithCachedSizesToArray(const_cast<uint8_t*>(slice.begin()));
   ::grpc::ByteBuffer tmp(&slice, 1);
   result->Swap(&tmp);
 }
diff --git a/paddle/fluid/operators/detail/grpc_server.cc b/paddle/fluid/operators/detail/grpc_server.cc
index 71acc568a90b26530caf0adfb3ec12a8e62f917a..09ca4cc05210e4514a4752e9eb6cb7ecff893471 100644
--- a/paddle/fluid/operators/detail/grpc_server.cc
+++ b/paddle/fluid/operators/detail/grpc_server.cc
@@ -259,7 +259,6 @@ void AsyncGRPCServer::TryToRegisterNewGetOne() {
 }
 
 void AsyncGRPCServer::TryToRegisterNewPrefetchOne() {
-  VLOG(4) << "TryToRegisterNewPrefetchOne in";
   std::unique_lock<std::mutex> lock(cq_mutex_);
   if (is_shut_down_) {
     VLOG(3) << "shutdown, do not TryToRegisterNewPrefetchOne";
diff --git a/paddle/fluid/operators/detail/grpc_server.h b/paddle/fluid/operators/detail/grpc_server.h
index dd5cf4b377cb8e4a53c9a161cb32985613de32eb..b0596d3cd1e108f28e8f1485d6b5c989c55be7e9 100644
--- a/paddle/fluid/operators/detail/grpc_server.h
+++ b/paddle/fluid/operators/detail/grpc_server.h
@@ -15,7 +15,8 @@ limitations under the License. */
 #pragma once
 
 #include <grpc++/grpc++.h>
-#include <thread>
+#include <string>
+#include <utility>
 
 #include "paddle/fluid/framework/executor.h"
 #include "paddle/fluid/framework/lod_tensor.h"
@@ -93,6 +94,7 @@ class AsyncGRPCServer final {
 
   // received variable from RPC, operators fetch variable from this queue.
   SimpleBlockQueue<MessageWithName> var_get_queue_;
+  // client send variable to this queue.
   ReceivedQueue var_recv_queue_;
 
   // condition of the sub program