55 lines
2.4 KiB
C
55 lines
2.4 KiB
C
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/*------------------------------------------------------------------------------*
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* Architecture & Implementation of DBMS *
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*------------------------------------------------------------------------------*
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* Copyright 2022 Databases and Information Systems Group TU Dortmund *
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* Visit us at *
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* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
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* OTHER DEALINGS IN THE SOFTWARE. *
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* *
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* Authors: *
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* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
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* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
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* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
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*------------------------------------------------------------------------------*
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*/
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#pragma once
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#include "replacement_strategy.h"
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#include <list>
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namespace beedb::buffer
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{
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class LRUKStrategy final : public ReplacementStrategy
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{
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public:
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LRUKStrategy(std::size_t count_frames, std::size_t k);
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~LRUKStrategy() override = default;
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std::size_t find_victim(std::vector<storage::Page> &pages) override;
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void on_pin(std::size_t frame_index, std::size_t timestamp) override;
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private:
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// Configured K-parameter.
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const std::size_t _k = 0;
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// List of timestamps for every page.
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std::vector<std::vector<std::size_t>> _history;
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[[nodiscard]] std::size_t last_timestamp(std::size_t frame_index) const
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{
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if (_history[frame_index].empty())
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{
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return std::numeric_limits<std::size_t>::max();
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}
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return _history[frame_index].back();
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}
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};
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} // namespace beedb::buffer
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