diff --git a/pglab/ASyncDBConnection.cpp b/pglab/ASyncDBConnection.cpp
index 633a034..c1e97e9 100644
--- a/pglab/ASyncDBConnection.cpp
+++ b/pglab/ASyncDBConnection.cpp
@@ -8,9 +8,9 @@ using namespace boost::asio;
 
 ASyncDBConnection::ASyncDBConnection(boost::asio::io_service &ios)
     : m_asioSock(ios)
-{
+{}
 
-}
+ASyncDBConnection::~ASyncDBConnection() = default;
 
 ASyncDBConnection::State ASyncDBConnection::state() const
 {
@@ -46,27 +46,30 @@ void ASyncDBConnection::setupConnection(const ConnectionConfig &config)
 
 void ASyncDBConnection::async_connect_handler(boost::system::error_code ec, std::size_t s)
 {
-    auto poll_state = m_connection.connectPoll();
-    if (poll_state == PGRES_POLLING_OK) {
-        // if connected return true
-        doStateCallback(State::Connected);
-    }
-    else if (poll_state == PGRES_POLLING_FAILED) {
-        doStateCallback(State::NotConnected);
-    }
-    else if (poll_state == PGRES_POLLING_READING) {
-        doStateCallback(State::Connecting);
-        m_asioSock.async_read_some(null_buffers(), 
-            [this] (boost::system::error_code ec, std::size_t s) 
-            { async_connect_handler(ec, s); }
-        );
-    }
-    else if (poll_state == PGRES_POLLING_WRITING) {
-        doStateCallback(State::Connecting);
-        m_asioSock.async_write_some(null_buffers(), 
-            [this] (boost::system::error_code ec, std::size_t s) 
-            { async_connect_handler(ec, s); }
-        );
+    // boost::asio::error::operation_aborted
+    if (ec == boost::system::errc::success) {
+        auto poll_state = m_connection.connectPoll();
+        if (poll_state == PGRES_POLLING_OK) {
+            // if connected return true
+            doStateCallback(State::Connected);
+        }
+        else if (poll_state == PGRES_POLLING_FAILED) {
+            doStateCallback(State::NotConnected);
+        }
+        else if (poll_state == PGRES_POLLING_READING) {
+            doStateCallback(State::Connecting);
+            m_asioSock.async_read_some(null_buffers(), 
+                [this] (boost::system::error_code ec, std::size_t s) 
+                { async_connect_handler(ec, s); }
+            );
+        }
+        else if (poll_state == PGRES_POLLING_WRITING) {
+            doStateCallback(State::Connecting);
+            m_asioSock.async_write_some(null_buffers(), 
+                [this] (boost::system::error_code ec, std::size_t s) 
+                { async_connect_handler(ec, s); }
+            );
+        }
     }
 }
 
@@ -74,6 +77,7 @@ void ASyncDBConnection::doStateCallback(State state)
 {
 	m_state = state;
     if (state == State::Connected) {
+        m_canceller = m_connection.getCancel();
         m_connection.setNoticeReceiver(
             [this](const PGresult *result) { processNotice(result); });
     }
@@ -93,7 +97,12 @@ void ASyncDBConnection::closeConnection()
 // 		m_thread.join();
 // 	}
     // SHould this be async too????
+    if (m_state == State::QuerySend) {
+        m_canceller.cancel(nullptr);
+    }
+    m_asioSock.close();
     m_connection.close();    
+    doStateCallback(State::NotConnected);
 }
 
 bool ASyncDBConnection::send(const std::string &command, on_result_callback on_result)
@@ -133,37 +142,39 @@ bool ASyncDBConnection::send(const std::string &command, Pgsql::Params params, o
 
 void ASyncDBConnection::async_query_handler(boost::system::error_code ec, std::size_t s, on_result_callback on_result)
 {
-    bool finished = false;
-    if (m_connection.consumeInput()) {
-        while ( ! finished && ! m_connection.isBusy()) {
-            auto res = m_connection.getResult();
-            qint64 ms = m_timer.restart();
-            on_result(res, ms);
-            if (res == nullptr) {
-                m_timer.invalidate();
-                doStateCallback(State::Connected);
-                finished = true;
+    if (ec == boost::system::errc::success) {
+        bool finished = false;
+        if (m_connection.consumeInput()) {
+            while ( ! finished && ! m_connection.isBusy()) {
+                auto res = m_connection.getResult();
+                qint64 ms = m_timer.restart();
+                on_result(res, ms);
+                if (res == nullptr) {
+                    m_timer.invalidate();
+                    doStateCallback(State::Connected);
+                    finished = true;
+                }
             }
+            // else is still waiting for more data
         }
-        // else is still waiting for more data
-    }
-    else {
-        // error during consume
+        else {
+            // error during consume
 
-    }
-    //return finished;
-    if (!finished) {
-        // wait for more
-        m_asioSock.async_read_some(null_buffers(), 
-                [this, on_result] (boost::system::error_code ec, std::size_t s) 
-                { async_query_handler(ec, s, on_result); }
-            );
+        }
+        //return finished;
+        if (!finished) {
+            // wait for more
+            m_asioSock.async_read_some(null_buffers(), 
+                    [this, on_result] (boost::system::error_code ec, std::size_t s) 
+                    { async_query_handler(ec, s, on_result); }
+                );
+        }
     }
 }
 
 bool ASyncDBConnection::cancel()
 {
-	return false; //m_threadData.cancel();
+	return m_canceller.cancel(nullptr);
 }
 
 void ASyncDBConnection::setStateCallback(on_state_callback state_callback)
diff --git a/pglab/ASyncDBConnection.h b/pglab/ASyncDBConnection.h
index 99dab70..622f41e 100644
--- a/pglab/ASyncDBConnection.h
+++ b/pglab/ASyncDBConnection.h
@@ -24,17 +24,18 @@ public:
 	enum class State {
 		NotConnected,
 		Connecting,
-		Connected,
-		QuerySend,
-		CancelSend,
-		Terminating
+		Connected, ///< connected and idle
+		QuerySend, ///< connected query send expecting result
+		CancelSend, ///< cancel send expecting result
+		Terminating ///< shutting down
 	};
 
 	using on_result_callback = std::function<void(std::shared_ptr<Pgsql::Result>, qint64)>;
 	using on_state_callback = std::function<void(State)>;
 	using on_notice_callback = std::function<void(Pgsql::ErrorDetails)>;
 
-	ASyncDBConnection(boost::asio::io_service &ios);
+	explicit ASyncDBConnection(boost::asio::io_service &ios);
+    ~ASyncDBConnection();
 
 	State state() const;
 //	void setupConnection(const std::string &connstring);
@@ -60,10 +61,12 @@ private:
     boost::asio::ip::tcp::socket m_asioSock;
 	ConnectionConfig m_config;
 	State m_state = State::NotConnected;
+    Pgsql::Canceller m_canceller;
     struct {
         std::mutex m_mutex;
         on_state_callback m_func;
     } m_stateCallback;
+    
     struct {
         std::mutex m_mutex;
         on_notice_callback m_func;