ClickHouse/dbms/include/DB/DataStreams/MergingAggregatedBlockInputStream.h
2015-03-12 05:22:55 +03:00

50 lines
1.3 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 Names & keys_names_,
const AggregateDescriptions & aggregates_, bool overflow_row_, bool final_, size_t max_threads_)
: aggregator(keys_names_, aggregates_, overflow_row_, 0, OverflowMode::THROW, nullptr, 0, 0),
final(final_), max_threads(max_threads_)
{
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:
Aggregator aggregator;
bool final;
size_t max_threads;
bool executed = false;
BlocksList blocks;
BlocksList::iterator it;
};
}