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

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#pragma once
#include <Yandex/logger_useful.h>
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#include <DB/Core/SortDescription.h>
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#include <DB/DataStreams/IProfilingBlockInputStream.h>
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namespace DB
{
/** Соединяет поток сортированных по отдельности блоков в сортированный целиком поток.
*/
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class MergeSortingBlockInputStream : public IProfilingBlockInputStream
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{
public:
MergeSortingBlockInputStream(BlockInputStreamPtr input_, SortDescription & description_)
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: input(input_), description(description_), has_been_read(false), log(&Logger::get("MergeSortingBlockInputStream"))
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{
children.push_back(input);
}
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String getName() const { return "MergeSortingBlockInputStream"; }
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BlockInputStreamPtr clone() { return new MergeSortingBlockInputStream(input, description); }
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protected:
Block readImpl();
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private:
BlockInputStreamPtr input;
SortDescription description;
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/// Всё было прочитано.
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bool has_been_read;
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Logger * log;
/** Слить сразу много блоков с помощью priority queue.
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*/
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Block merge(Blocks & blocks);
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};
}