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36 lines
901 B
C++
36 lines
901 B
C++
#pragma once
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#include <Core/SortDescription.h>
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#include <DataStreams/IBlockInputStream.h>
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namespace DB
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{
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/** Sorts each block individually by the values of the specified columns.
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* At the moment, not very optimal algorithm is used.
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*/
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class PartialSortingBlockInputStream : public IBlockInputStream
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{
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public:
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/// limit - if not 0, then you can sort each block not completely, but only `limit` first rows by order.
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PartialSortingBlockInputStream(const BlockInputStreamPtr & input_, SortDescription & description_, UInt64 limit_ = 0)
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: description(description_), limit(limit_)
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{
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children.push_back(input_);
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}
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String getName() const override { return "PartialSorting"; }
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Block getHeader() const override { return children.at(0)->getHeader(); }
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protected:
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Block readImpl() override;
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private:
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SortDescription description;
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UInt64 limit;
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};
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}
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