HashGroupByPhysicalOperator类 参考

Group By Hash 方式物理算子 更多...

#include <hash_group_by_physical_operator.h>

类 HashGroupByPhysicalOperator 继承关系图:

Public 成员函数
	HashGroupByPhysicalOperator (vector< unique_ptr< Expression > > &&group_by_exprs, vector< Expression * > &&expressions)
PhysicalOperatorType	type () const override
OpType	get_op_type () const override
RC	open (Trx *trx) override
RC	next () override
RC	close () override
Tuple *	current_tuple () override
Public 成员函数 继承自 GroupByPhysicalOperator
	GroupByPhysicalOperator (vector< Expression * > &&expressions)
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 类型
using	AggregatorList = GroupByPhysicalOperator::AggregatorList
using	GroupValueType = GroupByPhysicalOperator::GroupValueType
using	GroupType = tuple< ValueListTuple, GroupValueType >
	聚合出来的一组数据

Private 成员函数
RC	find_group (const Tuple &child_tuple, GroupType *&found_group)

Private 属性
vector< unique_ptr< Expression > >	group_by_exprs_
vector< GroupType >	groups_
	一组一条数据 pair的first是group by 的值列表，second是计算出来的表达式值列表 TODO 改成hash/unordered_map
vector< GroupType >::iterator	current_group_
bool	first_emited_ = false

额外继承的成员函数
Protected 类型 继承自 GroupByPhysicalOperator
using	AggregatorList = vector< unique_ptr< Aggregator > >
using	GroupValueType = tuple< AggregatorList, CompositeTuple >
	聚合出来的一组数据 更多...
Protected 成员函数 继承自 GroupByPhysicalOperator
void	create_aggregator_list (AggregatorList &aggregator_list)
RC	aggregate (AggregatorList &aggregator_list, const Tuple &tuple)
	聚合一条记录 更多...
RC	evaluate (GroupValueType &group_value)
	所有tuple聚合结束后，运算最终结果
Protected 属性 继承自 GroupByPhysicalOperator
vector< Expression * >	aggregate_expressions_
vector< Expression * >	value_expressions_
	聚合表达式
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

Group By Hash 方式物理算子

通过 hash 的方式进行 group by 操作。当聚合函数存在 group by 表达式时，默认采用这个物理算子（当前也只有这个物理算子）。 NOTE: 当前并没有使用hash方式实现，而是每次使用线性查找的方式。

成员函数说明

close()

RC HashGroupByPhysicalOperator::close ( )

overridevirtual

实现了 PhysicalOperator.

current_tuple()

Tuple * HashGroupByPhysicalOperator::current_tuple ( )

overridevirtual

重载 PhysicalOperator .

get_op_type()

OpType HashGroupByPhysicalOperator::get_op_type ( ) const

inlineoverridevirtual

TODO: add this function TODO: unify logical and physical OpType

重载 OperatorNode .

next()

RC HashGroupByPhysicalOperator::next ( )

overridevirtual

重载 PhysicalOperator .

open()

RC HashGroupByPhysicalOperator::open ( Trx *  trx )

overridevirtual

实现了 PhysicalOperator.

type()

PhysicalOperatorType HashGroupByPhysicalOperator::type ( ) const

inlineoverridevirtual

实现了 PhysicalOperator.

---

该类的文档由以下文件生成:

• src/observer/sql/operator/hash_group_by_physical_operator.h
• src/observer/sql/operator/hash_group_by_physical_operator.cpp