ClickHouse/src/Processors/QueryPlan/AggregatingStep.h

#pragma once
#include <Processors/QueryPlan/ITransformingStep.h>
#include <DataStreams/SizeLimits.h>
#include <Storages/SelectQueryInfo.h>
#include <Interpreters/Aggregator.h>

namespace DB
{

struct AggregatingTransformParams;
using AggregatingTransformParamsPtr = std::shared_ptr<AggregatingTransformParams>;

/// Aggregation. See AggregatingTransform.
class AggregatingStep : public ITransformingStep
{
public:
    AggregatingStep(
        const DataStream & input_stream_,
        Aggregator::Params params_,
        bool final_,
        size_t max_block_size_,
        size_t merge_threads_,
        size_t temporary_data_merge_threads_,
        bool storage_has_evenly_distributed_read_,
        InputOrderInfoPtr group_by_info_,
        SortDescription group_by_sort_description_);

    String getName() const override { return "Aggregating"; }

    void transformPipeline(QueryPipeline & pipeline, const BuildQueryPipelineSettings &) override;

    void describeActions(FormatSettings &) const override;
    void describePipeline(FormatSettings & settings) const override;

    const Aggregator::Params & getParams() const { return params; }

private:
    Aggregator::Params params;
    bool final;
    size_t max_block_size;
    size_t merge_threads;
    size_t temporary_data_merge_threads;

    bool storage_has_evenly_distributed_read;

    InputOrderInfoPtr group_by_info;
    SortDescription group_by_sort_description;

    Processors aggregating_in_order;
    Processors aggregating_sorted;
    Processors finalizing;

    Processors aggregating;

};

}