beedb/include/execution/index_scan_operator.h

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2022-04-04 20:25:01 +02:00
/*------------------------------------------------------------------------------*
* Architecture & Implementation of DBMS *
*------------------------------------------------------------------------------*
* Copyright 2022 Databases and Information Systems Group TU Dortmund *
* Visit us at *
* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
* OTHER DEALINGS IN THE SOFTWARE. *
* *
* Authors: *
* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
*------------------------------------------------------------------------------*
*/
#pragma once
#include "operator_interface.h"
#include "tuple_buffer.h"
#include <buffer/manager.h>
#include <index/index_interface.h>
#include <memory>
#include <queue>
#include <storage/page.h>
#include <table/table.h>
#include <table/table_disk_manager.h>
#include <table/tuple.h>
#include <unordered_set>
#include <vector>
namespace beedb::execution
{
/**
* Key (range) that have to be looked up in the.
* May be a range or a single key.
*/
class KeyRange
{
public:
explicit KeyRange(const std::int64_t single_key) : _from(single_key), _to(std::numeric_limits<std::int64_t>::max())
{
}
KeyRange(const std::int64_t from, const std::int64_t to) : _from(from), _to(to)
{
}
~KeyRange() = default;
[[nodiscard]] bool is_single_key() const
{
return _to == std::numeric_limits<std::int64_t>::max();
}
[[nodiscard]] std::int64_t single_key() const
{
return _from;
}
[[nodiscard]] std::int64_t from() const
{
return _from;
}
[[nodiscard]] std::int64_t to() const
{
return _to;
}
bool operator<(const KeyRange &other) const
{
return _from < other._from;
}
bool operator==(const KeyRange &other) const
{
return _from == other._from && _to == other._to;
}
private:
const std::int64_t _from;
const std::int64_t _to;
};
} // namespace beedb::execution
namespace std
{
template <> struct hash<beedb::execution::KeyRange>
{
public:
std::size_t operator()(const beedb::execution::KeyRange &range) const
{
return std::hash<std::int64_t>()(range.from()) ^ std::hash<std::int64_t>()(range.to());
}
};
} // namespace std
namespace beedb::execution
{
/**
* Takes an index and keys to be looked up in the index
* and scans only over pages found in the index instead
* of scanning all pages from the table.
*/
class IndexScanOperator final : public OperatorInterface
{
public:
IndexScanOperator(concurrency::Transaction *transaction, const std::uint32_t scan_page_limit,
const table::Schema &schema, buffer::Manager &buffer_manager,
table::TableDiskManager &table_disk_manager, std::unordered_set<KeyRange> &&key_ranges,
std::shared_ptr<index::IndexInterface> index);
~IndexScanOperator() override = default;
void open() override;
util::optional<table::Tuple> next() override;
void close() override;
[[nodiscard]] const table::Schema &schema() const override
{
return _schema;
}
private:
const std::uint32_t _scan_page_limit;
const table::Schema _schema;
buffer::Manager &_buffer_manager;
table::TableDiskManager &_table_disk_manager;
std::unordered_set<KeyRange> _key_ranges;
std::shared_ptr<index::IndexInterface> _index;
std::queue<storage::Page::id_t> _pages_to_scan;
std::vector<storage::Page::id_t> _pinned_pages;
TupleBuffer _buffer;
};
} // namespace beedb::execution