Function addMergingFinal

src/QueryPlan/ReadFromMergeTree.cpp:858–962

}

static void addMergingFinal(
    Pipe & pipe,
    size_t num_output_streams,
    const SortDescription & sort_description,
    MergeTreeMetaBase::MergingParams merging_params,
    Names partition_key_columns,
    size_t max_block_size)
{
    const auto & header = pipe.getHeader();
    size_t num_outputs = pipe.numOutputPorts();

    auto get_merging_processor = [&]() -> MergingTransformPtr
    {
        switch (merging_params.mode)
        {
            case MergeTreeMetaBase::MergingParams::Ordinary:
            {
                return std::make_shared<MergingSortedTransform>(header, num_outputs,
                           sort_description, max_block_size);
            }

            case MergeTreeMetaBase::MergingParams::Collapsing:
                return std::make_shared<CollapsingSortedTransform>(header, num_outputs,
                           sort_description, merging_params.sign_column, true, max_block_size);

            case MergeTreeMetaBase::MergingParams::Summing:
                return std::make_shared<SummingSortedTransform>(header, num_outputs,
                           sort_description, merging_params.columns_to_sum, partition_key_columns, max_block_size);

            case MergeTreeMetaBase::MergingParams::Aggregating:
                return std::make_shared<AggregatingSortedTransform>(header, num_outputs,
                           sort_description, max_block_size);

            case MergeTreeMetaBase::MergingParams::Replacing:
                return std::make_shared<ReplacingSortedTransform>(header, num_outputs,
                           sort_description, merging_params.version_column, max_block_size);

            case MergeTreeMetaBase::MergingParams::VersionedCollapsing:
                return std::make_shared<VersionedCollapsingTransform>(header, num_outputs,
                           sort_description, merging_params.sign_column, max_block_size);

            case MergeTreeMetaBase::MergingParams::Graphite:
                throw Exception("GraphiteMergeTree doesn't support FINAL", ErrorCodes::LOGICAL_ERROR);
        }

        __builtin_unreachable();
    };

    if (num_output_streams <= 1 || sort_description.empty())
    {
        pipe.addTransform(get_merging_processor());
        return;
    }

    ColumnNumbers key_columns;
    key_columns.reserve(sort_description.size());

    for (const auto & desc : sort_description)