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29 lines
644 B
C++
29 lines
644 B
C++
#pragma once
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#include <Processors/ISimpleTransform.h>
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#include <Common/HashTable/HashMap.h>
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#include <Common/UInt128.h>
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namespace DB
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{
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class LimitByTransform : public ISimpleTransform
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{
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public:
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LimitByTransform(const Block & header, size_t group_length_, size_t group_offset_, const Names & columns);
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String getName() const override { return "LimitByTransform"; }
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protected:
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void transform(Chunk & chunk) override;
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private:
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using MapHashed = HashMap<UInt128, UInt64, UInt128TrivialHash>;
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MapHashed keys_counts;
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std::vector<size_t> key_positions;
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const size_t group_length;
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const size_t group_offset;
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};
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}
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