Found in stress test: https://gist.github.com/alesapin/5cd6b8901488a1f170d5ef389900a534
Report: https://s3.amazonaws.com/clickhouse-test-reports/31158/7fb9a42b119b6c3eba1784caaabde51c1ded3384/stress_tests__debug__actions_.html
Block header, AggregatingTransformParamsPtr params_,
    const SortDescription & group_by_description_,
    size_t max_block_size_, size_t max_block_bytes_,
    ManyAggregatedDataPtr many_data_, size_t current_variant)
    : IProcessor({std::move(header)}, {params_->getCustomHeader(false)})
    , max_block_size(max_block_size_)
    , max_block_bytes(max_block_bytes_)
    , params(std::move(params_))
    , group_by_description(group_by_description_)
    , aggregate_columns(params->params.aggregates_size)
    , many_data(std::move(many_data_))
    , variants(*many_data->variants[current_variant])
{
    
    res_header = params->getCustomHeader(false);
    
    for (auto & column_description : group_by_description)
    {
        if (!column_description.column_name.empty())
        {
            column_description.column_number = res_header.getPositionByName(column_description.column_name);
            column_description.column_name.clear();
        }
    }
}
AggregatingInOrderTransform::~AggregatingInOrderTransform() = default;