diff --git a/examples/echo_server/echo_server.cpp b/examples/echo_server/echo_server.cpp
index 616b8c28880ecc4bb010a47e6308ae1f20e8ae8e..3595bed18fb9af6c60760a077ec158820d4737af 100644
--- a/examples/echo_server/echo_server.cpp
+++ b/examples/echo_server/echo_server.cpp
@@ -8,7 +8,7 @@
 //#define ASCS_SYNC_DISPATCH //do not open this feature, see below for more details
 #define ASCS_DISPATCH_BATCH_MSG
 #define ASCS_ENHANCED_STABILITY
-#define ASCS_FULL_STATISTIC //full statistic will slightly impact efficiency
+//#define ASCS_FULL_STATISTIC //full statistic will slightly impact efficiency
 #define ASCS_USE_STEADY_TIMER
 #define ASCS_ALIGNED_TIMER
 #define ASCS_AVOID_AUTO_STOP_SERVICE
diff --git a/include/ascs/base.h b/include/ascs/base.h
index 76a365dd28742b2c9148fcc15572a28c33574f91..a46d50350e9d7b015fd8b8e75f12b8a70be9f349 100644
--- a/include/ascs/base.h
+++ b/include/ascs/base.h
@@ -488,6 +488,14 @@ size_t get_size_in_byte(const _Can& __can)
 	return size_in_byte;
 }
 
+template<typename _Can>
+size_t get_size_in_byte(const _Can& __can, size_t& size)
+{
+	auto size_in_byte = size = 0;
+	do_something_to_all(__can, [&size_in_byte, &size](typename _Can::const_reference item) {size_in_byte += item.size(); ++size;});
+	return size_in_byte;
+}
+
 //member functions, used to do something to any member container(except map and multimap) optionally with any member mutex
 #define DO_SOMETHING_TO_ALL_MUTEX(CAN, MUTEX) DO_SOMETHING_TO_ALL_MUTEX_NAME(do_something_to_all, CAN, MUTEX)
 #define DO_SOMETHING_TO_ALL(CAN) DO_SOMETHING_TO_ALL_NAME(do_something_to_all, CAN)
diff --git a/include/ascs/socket.h b/include/ascs/socket.h
index bc53f1f7d4622e414372c8596708bcacffed3b06..668e73268083e571589c7562e14275cc7f074bff 100644
--- a/include/ascs/socket.h
+++ b/include/ascs/socket.h
@@ -370,8 +370,9 @@ protected:
 
 	bool handle_msg()
 	{
-		auto size_in_byte = ascs::get_size_in_byte(temp_msg_can);
-		stat.recv_msg_sum += temp_msg_can.size(); //this can have linear complexity in old gcc or Cygwin and Mingw64, please note.
+		size_t size = 0;
+		auto size_in_byte = ascs::get_size_in_byte(temp_msg_can, size);
+		stat.recv_msg_sum += size;
 		stat.recv_byte_sum += size_in_byte;
 #ifdef ASCS_SYNC_RECV
 		std::unique_lock<std::mutex> lock(sync_recv_mutex);
diff --git a/include/ascs/tcp/socket.h b/include/ascs/tcp/socket.h
index a60a8fd10e294eace9857b2b4cebca301b3ef844..2167cc37d2b023823de0eb6db939af74092cdbba 100644
--- a/include/ascs/tcp/socket.h
+++ b/include/ascs/tcp/socket.h
@@ -300,18 +300,16 @@ private:
 #else
 		send_msg_buffer.move_items_out(asio::detail::default_max_transfer_size, last_send_msg);
 #endif
-		std::vector<asio::const_buffer> bufs;
-		bufs.reserve(last_send_msg.size());
-		for (auto iter = std::begin(last_send_msg); iter != std::end(last_send_msg); ++iter)
-		{
-			stat.send_delay_sum += end_time - iter->begin_time;
-			bufs.emplace_back(iter->data(), iter->size());
-		}
+		send_bufs.clear(); //this buffer will not be refreshed according to last_send_msg timely
+		ascs::do_something_to_all(last_send_msg, [this, &end_time](typename super::in_msg& item) {
+			this->stat.send_delay_sum += end_time - item.begin_time;
+			this->send_bufs.emplace_back(item.data(), item.size());
+		});
 
-		if ((sending = !bufs.empty()))
+		if ((sending = !send_bufs.empty()))
 		{
 			last_send_msg.front().restart();
-			asio::async_write(this->next_layer(), bufs, make_strand_handler(strand,
+			asio::async_write(this->next_layer(), send_bufs, make_strand_handler(strand,
 				this->make_handler_error_size([this](const asio::error_code& ec, size_t bytes_transferred) {this->send_handler(ec, bytes_transferred);})));
 			return true;
 		}
@@ -327,7 +325,7 @@ private:
 
 			stat.send_byte_sum += bytes_transferred;
 			stat.send_time_sum += statistic::now() - last_send_msg.front().begin_time;
-			stat.send_msg_sum += last_send_msg.size();
+			stat.send_msg_sum += send_bufs.size();
 #ifdef ASCS_SYNC_SEND
 			ascs::do_something_to_all(last_send_msg, [](typename super::in_msg& item) {if (item.p) {item.p->set_value(sync_call_result::SUCCESS);}});
 #endif
@@ -391,6 +389,7 @@ private:
 
 	std::shared_ptr<i_unpacker<out_msg_type>> unpacker_;
 	typename super::in_container_type last_send_msg;
+	std::vector<asio::const_buffer> send_bufs; //just to reduce memory allocation and keep the size of sending items (linear complexity, it's very important)
 	asio::io_context::strand strand;
 };