Method receiveResult

programs/client/Client.cpp:2060–2126

Receives and processes packets coming from server. Also checks if query execution should be cancelled.

    /// Receives and processes packets coming from server.
    /// Also checks if query execution should be cancelled.
    void receiveResult()
    {
        InterruptListener interrupt_listener;
        bool cancelled = false;

        // TODO: get the poll_interval from commandline.
        const auto receive_timeout = connection_parameters.timeouts.receive_timeout;
        constexpr size_t default_poll_interval = 1000000; /// in microseconds
        constexpr size_t min_poll_interval = 5000; /// in microseconds
        const size_t poll_interval
            = std::max(min_poll_interval, std::min<size_t>(receive_timeout.totalMicroseconds(), default_poll_interval));

        while (true)
        {
            Stopwatch receive_watch(CLOCK_MONOTONIC_COARSE);

            while (true)
            {
                /// Has the Ctrl+C been pressed and thus the query should be cancelled?
                /// If this is the case, inform the server about it and receive the remaining packets
                /// to avoid losing sync.
                if (!cancelled)
                {
                    auto cancel_query = [&] {
                        connection->sendCancel();
                        cancelled = true;
                        if (is_interactive)
                        {
                            progress_indication.clearProgressOutput();
                            std::cout << "Cancelling query." << std::endl;
                        }

                        /// Pressing Ctrl+C twice results in shut down.
                        interrupt_listener.unblock();
                    };

                    if (interrupt_listener.check())
                    {
                        cancel_query();
                    }
                    else
                    {
                        double elapsed = receive_watch.elapsedSeconds();
                        if (elapsed > receive_timeout.totalSeconds())
                        {
                            std::cout << "Timeout exceeded while receiving data from server."
                                      << " Waited for " << static_cast<size_t>(elapsed) << " seconds,"
                                      << " timeout is " << receive_timeout.totalSeconds() << " seconds." << std::endl;

                            cancel_query();
                        }
                    }
                }

                /// Poll for changes after a cancellation check, otherwise it never reached
                /// because of progress updates from server.
                if (connection->poll(poll_interval))
                    break;