Method addPerStreamLimitByIfNeeded

src/Processors/QueryPlan/SortingStep.cpp:280–295

}

void SortingStep::addPerStreamLimitByIfNeeded(QueryPipelineBuilder & pipeline, const SortDescription & stream_sort_desc)
{
    if (limit_by_columns.empty() || pipeline.getNumStreams() <= 1)
        return;

    if (getCollationAwareSortPrefixInColumns(stream_sort_desc, limit_by_columns).size() != limit_by_columns.size())
        return;

    pipeline.addSimpleTransform(
        [&](const SharedHeader & header, QueryPipelineBuilder::StreamType stream_type) -> ProcessorPtr
        {
            if (stream_type != QueryPipelineBuilder::StreamType::Main)
                return nullptr;
            return std::make_shared<LimitBySortedStreamTransform>(header, limit_by_group_length, 0, limit_by_columns);
        });
}

void SortingStep::updateLimit(size_t limit_)
{