最简单的两表（称为左表、右表）join算子更多...

#include <join_physical_operator.h>

类 NestedLoopJoinPhysicalOperator 继承关系图:

Public 成员函数
PhysicalOperatorType	type () const override

RC	open (Trx *trx) override

RC	next () override

RC	close () override

Tuple *	current_tuple () override

PhysicalOperatorType	type () const override

OpType	get_op_type () const override

virtual double	calculate_cost (LogicalProperty prop, const vector< LogicalProperty > &child_log_props, CostModel *cm) override
	Calculates the cost of a logical operation. 更多...

RC	open (Trx *trx) override

RC	next () override

RC	close () override

Tuple *	current_tuple () override

Public 成员函数继承自 PhysicalOperator
virtual string	name () const

virtual string	param () const

bool	is_physical () const override

bool	is_logical () const override

virtual PhysicalOperatorType	type () const =0

virtual RC	open (Trx *trx)=0

virtual RC	next ()

virtual RC	next (Chunk &chunk)

virtual RC	close ()=0

virtual Tuple *	current_tuple ()

virtual RC	tuple_schema (TupleSchema &schema) const

void	add_child (unique_ptr< PhysicalOperator > oper)

vector< unique_ptr< PhysicalOperator > > &	children ()

Public 成员函数继承自 OperatorNode
virtual OpType	get_op_type () const

virtual bool	is_physical () const =0

virtual bool	is_logical () const =0

virtual uint64_t	hash () const

virtual bool	operator== (const OperatorNode &other) const

virtual unique_ptr< LogicalProperty >	find_log_prop (const vector< LogicalProperty * > &log_props)
	Generate the logical property of the operator node using the input logical properties. 更多...

virtual double	calculate_cost (LogicalProperty prop, const vector< LogicalProperty > &child_log_props, CostModel *cm)
	Calculates the cost of a logical operation. 更多...

void	add_general_child (OperatorNode *child)

vector< OperatorNode * > &	get_general_children ()

Private 成员函数
RC	left_next ()

RC	right_next ()
	左表遍历下一条数据

RC	left_next ()

RC	right_next ()
	左表遍历下一条数据

Private 属性
Trx *	trx_ = nullptr
	右表遍历下一条数据，如果上一轮结束了就重新开始新的一轮

PhysicalOperator *	left_ = nullptr
	左表右表的真实对象是在PhysicalOperator::children_中，这里是为了写的时候更简单

PhysicalOperator *	right_ = nullptr

Tuple *	left_tuple_ = nullptr

Tuple *	right_tuple_ = nullptr

JoinedTuple	joined_tuple_

bool	round_done_ = true
	当前关联的左右两个tuple

bool	right_closed_ = true
	右表遍历的一轮是否结束

额外继承的成员函数
Protected 属性继承自 PhysicalOperator
vector< unique_ptr< PhysicalOperator > >	children_

Protected 属性继承自 OperatorNode
vector< OperatorNode * >	general_children_

详细描述

最简单的两表（称为左表、右表）join算子

依次遍历左表的每一行，然后关联右表的每一行

成员函数说明

◆ calculate_cost()

virtual double NestedLoopJoinPhysicalOperator::calculate_cost	(	LogicalProperty *	prop,
		const vector< LogicalProperty * > &	child_log_props,
		CostModel *	cm
	)

inlineoverridevirtual

Calculates the cost of a logical operation.

This function is intended to be overridden in derived classes. It calculates the cost associated with a specific logical property, taking into account the provided child logical properties and a cost model.

参数

prop	A pointer to the logical property for which the cost is being calculated.
child_log_props	A vector containing pointers to child logical properties.
cm	A pointer to the cost model used for calculating the cost.