#27685
{
    ExtraBlockPtr tmp;
    join->joinBlock(header, tmp);
    return header;
}
JoiningTransform::JoiningTransform(
    Block input_header,
    JoinPtr join_,
    size_t max_block_size_,
    bool on_totals_,
    bool default_totals_,
    FinishCounterPtr finish_counter_)
    : IProcessor({input_header}, {transformHeader(input_header, join_)})
    , join(std::move(join_))
    , on_totals(on_totals_)
    , default_totals(default_totals_)
    , finish_counter(std::move(finish_counter_))
    , max_block_size(max_block_size_)
{
    if (!join->isFilled())
        inputs.emplace_back(Block(), this);
}
IProcessor::Status JoiningTransform::prepare()