ClickHouse/dbms/include/DB/DataStreams/MergingAggregatedBlockInputStream.h

52 lines
1.5 KiB
C++

#pragma once
#include <DB/Interpreters/Aggregator.h>
#include <DB/DataStreams/IProfilingBlockInputStream.h>
namespace DB
{
using Poco::SharedPtr;
/** Доагрегирует поток блоков, в котором каждый блок уже агрегирован.
* Агрегатные функции в блоках не должны быть финализированы, чтобы их состояния можно было объединить.
*/
class MergingAggregatedBlockInputStream : public IProfilingBlockInputStream
{
public:
MergingAggregatedBlockInputStream(BlockInputStreamPtr input_, const ColumnNumbers & keys_,
const AggregateDescriptions & aggregates_, bool overflow_row_, bool final_)
: aggregator(new Aggregator(keys_, aggregates_, overflow_row_)), final(final_), has_been_read(false)
{
children.push_back(input_);
}
MergingAggregatedBlockInputStream(BlockInputStreamPtr input_, const Names & keys_names_,
const AggregateDescriptions & aggregates_, bool overflow_row_, bool final_)
: aggregator(new Aggregator(keys_names_, aggregates_, overflow_row_)), final(final_), has_been_read(false)
{
children.push_back(input_);
}
String getName() const override { return "MergingAggregatedBlockInputStream"; }
String getID() const override
{
std::stringstream res;
res << "MergingAggregated(" << children.back()->getID() << ", " << aggregator->getID() << ")";
return res.str();
}
protected:
Block readImpl() override;
private:
SharedPtr<Aggregator> aggregator;
bool final;
bool has_been_read;
};
}