ClickHouse/dbms/src/DataStreams/MergingAggregatedBlockInputStream.h
2017-05-14 19:03:55 +04:00

46 lines
1.1 KiB
C++

#pragma once
#include <Interpreters/Aggregator.h>
#include <DataStreams/IProfilingBlockInputStream.h>
namespace DB
{
/** A pre-aggregate stream of blocks in which each block is already aggregated.
* Aggregate functions in blocks should not be finalized so that their states can be merged.
*/
class MergingAggregatedBlockInputStream : public IProfilingBlockInputStream
{
public:
MergingAggregatedBlockInputStream(BlockInputStreamPtr input_, const Aggregator::Params & params, bool final_, size_t max_threads_)
: aggregator(params), final(final_), max_threads(max_threads_)
{
children.push_back(input_);
}
String getName() const override { return "MergingAggregated"; }
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;
};
}