Method nextImpl

src/IO/WriteBufferFromFileDescriptor.cpp:64–98

void WriteBufferFromFileDescriptor::nextImpl()
{
    if (!offset())
        return;

    Stopwatch watch;

    if (throttler)
        throttler->add(offset());

    size_t bytes_written = 0;
    while (bytes_written != offset())
    {
        ProfileEvents::increment(ProfileEvents::WriteBufferFromFileDescriptorWrite);

        ssize_t res = 0;
        {
            CurrentMetrics::Increment metric_increment{CurrentMetrics::Write};
            res = ::write(fd, working_buffer.begin() + bytes_written, offset() - bytes_written);
        }

        if ((-1 == res || 0 == res) && errno != EINTR)
        {
            ProfileEvents::increment(ProfileEvents::WriteBufferFromFileDescriptorWriteFailed);
            throwFromErrnoWithPath("Cannot write to file " + getFileName(), getFileName(),
                                   ErrorCodes::CANNOT_WRITE_TO_FILE_DESCRIPTOR);
        }

        if (res > 0)
            bytes_written += res;
    }

    ProfileEvents::increment(ProfileEvents::DiskWriteElapsedMicroseconds, watch.elapsedMicroseconds());
    ProfileEvents::increment(ProfileEvents::WriteBufferFromFileDescriptorWriteBytes, bytes_written);
}


/// Name or some description of file.