Method cancel

src/DataStreams/RemoteQueryExecutorReadContext.cpp:183–214

}

void RemoteQueryExecutorReadContext::cancel()
{
    std::lock_guard guard(fiber_lock);

    /// It is safe to just destroy fiber - we are not in the process of reading from socket.
    boost::context::fiber to_destroy = std::move(fiber);

    /// One should not try to wait for the current packet here in case of
    /// timeout because this will exceed the timeout.
    /// Anyway if the timeout is exceeded, then the connection will be shutdown
    /// (disconnected), so it will not left in an unsynchronised state.
    if (!is_timer_alarmed)
    {
        /// Wait for current pending packet, to avoid leaving connection in unsynchronised state.
        while (is_read_in_progress.load(std::memory_order_relaxed))
        {
            checkTimeout(/* blocking= */ true);
            to_destroy = std::move(to_destroy).resume();
        }
    }

    /// Send something to pipe to cancel executor waiting.
    uint64_t buf = 0;
    while (-1 == write(pipe_fd[1], &buf, sizeof(buf)))
    {
        if (errno == EAGAIN)
            break;

        if (errno != EINTR)
            throwFromErrno("Cannot write to pipe", ErrorCodes::CANNOT_READ_FROM_SOCKET);
    }
}

RemoteQueryExecutorReadContext::~RemoteQueryExecutorReadContext()
{