110 lines
3.5 KiB
C
110 lines
3.5 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 "binary_operator.h"
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#include "tuple_buffer.h"
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#include <memory>
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#include <string>
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#include <table/memory_table.h>
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#include <table/schema.h>
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#include <table/tuple.h>
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#include <unordered_map>
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#include <utility>
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#include <vector>
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namespace beedb::execution
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{
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/**
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* Hash table for hash join.
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*/
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class HashTable
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{
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public:
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explicit HashTable(const std::uint32_t key_index) : _key_index(key_index)
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{
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}
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~HashTable() = default;
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bool contains(const table::Value &key)
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{
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return this->_map.find(key) != _map.end();
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}
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void put(const table::Tuple &tuple)
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{
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table::Tuple in_memory_tuple(tuple);
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this->_map[tuple.get(_key_index)].push_back(std::move(in_memory_tuple));
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}
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const std::vector<table::Tuple> &get(const table::Value &key)
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{
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return _map[key];
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}
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private:
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const std::uint32_t _key_index;
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std::unordered_map<table::Value, std::vector<table::Tuple>> _map;
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};
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/**
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* Operator that joins two sources using a hash table over
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* the left source.
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*/
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class HashJoinOperator final : public BinaryOperator
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{
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public:
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HashJoinOperator(concurrency::Transaction *transaction, table::Schema &&schema, const std::uint32_t left_index,
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const std::uint32_t right_index);
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~HashJoinOperator() override = default;
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void open() override;
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util::optional<table::Tuple> next() override;
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void close() override;
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[[nodiscard]] const table::Schema &schema() const override
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{
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return _schema;
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}
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private:
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const table::Schema _schema;
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const std::uint32_t _left_index;
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const std::uint32_t _right_index;
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HashTable _hash_table;
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bool _is_built = false;
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TupleBuffer _tuple_buffer;
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/**
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* Builds the hash table.
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*/
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void build_hash_table();
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/**
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* Probes the hash table.
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*/
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util::optional<table::Tuple> probe_hash_table();
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};
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} // namespace beedb::execution
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