beedb/include/plan/optimizer/rule/predicate_push_down_optimiz...

68 lines
3.3 KiB
C++

/*------------------------------------------------------------------------------*
* 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 "optimizer_rule_interface.h"
#include <expression/operation.h>
#include <expression/term.h>
#include <memory>
#include <vector>
namespace beedb::plan::logical
{
class PredicatePushDownOptimizationRule final : public OptimizerRuleInterface
{
public:
PredicatePushDownOptimizationRule() = default;
~PredicatePushDownOptimizationRule() override = default;
bool optimize(PlanView &plan) override;
private:
/**
* Checks if the schema of a given node contains all
* attributes needed by the given predicate.
*
* @param node Node to check.
* @param predicate Predicate with attributes that are required.
* @return True, if the schema of the node contains all needed attributes. False otherwise.
*/
[[nodiscard]] static bool provides_needed_attributes(PlanView::node_t node,
const std::unique_ptr<expression::Operation> &predicate);
/**
* Determines the lowest node in the plan that could
* work as the child of a given selection. To do so,
* the node that is returned by this function has to
* provide all attributes needed by the predicate.
* The further down the logical plan, the better.
*
* @param plan Logical plan.
* @param current_node Node to start the search.
* @param predicate Predicate to push down.
* @return The node that could work as "the lowest" child.
*/
[[nodiscard]] static PlanView::node_t determine_lowest_position(
const PlanView &plan, PlanView::node_t current_node, const std::unique_ptr<expression::Operation> &predicate);
};
} // namespace beedb::plan::logical