CompanionSetCollection Class Reference

The collection of CompanionSet objects for a given JoinHypergraph. More...

#include <relational_expression.h>

Public Member Functions
	CompanionSetCollection (THD *thd, struct RelationalExpression *root)
	CompanionSetCollection (const CompanionSetCollection &)=delete
	No copying. More...
CompanionSetCollection &	operator= (const CompanionSetCollection &)=delete
CompanionSet *	Find (table_map tables)
const CompanionSet *	Find (table_map tables) const
std::string	ToString () const
	For trace and debugging. More...

Private Member Functions
void	Compute (THD *thd, RelationalExpression *expr, CompanionSet *current_set)
	Compute the CompanionSet of 'expr' and all of its descendants. More...
CompanionSet *	FindInternal (table_map tables) const
	For a given set of tables, find the CompanionSet they are part of Returns nullptr if the tables are in different (i.e., incompatible) CompanionSet instances. More...

Private Attributes
std::array< CompanionSet *, MAX_TABLES >	m_table_num_to_companion_set {nullptr}
	A mapping from table number to CompanionSet. More...

Detailed Description

The collection of CompanionSet objects for a given JoinHypergraph.

Constructor & Destructor Documentation

CompanionSetCollection() [1/2]

CompanionSetCollection::CompanionSetCollection ( THD *  thd, struct RelationalExpression *  root  )

inline

CompanionSetCollection() [2/2]

CompanionSetCollection::CompanionSetCollection ( const CompanionSetCollection &  )

delete

No copying.

Member Function Documentation

Compute()

void CompanionSetCollection::Compute ( THD *  thd, RelationalExpression *  expr, CompanionSet *  current_set  )

private

Compute the CompanionSet of 'expr' and all of its descendants.

Parameters

thd	The current thread.
expr	Compute CompanionSet of this and all of its descendants.
current_set	The CompanionSet to which 'expr' will belong, or nullptr if 'expr' is the root of a new set.

Find() [1/2]

CompanionSet * CompanionSetCollection::Find ( table_map  tables )

inline

Find() [2/2]

const CompanionSet * CompanionSetCollection::Find ( table_map  tables ) const

inline

FindInternal()

CompanionSet * CompanionSetCollection::FindInternal ( table_map  tables ) const

private

For a given set of tables, find the CompanionSet they are part of Returns nullptr if the tables are in different (i.e., incompatible) CompanionSet instances.

If so, a condition using this set of tables can not induce a new (cycle) edge in the hypergraph, as there are non-inner joins in the way.

operator=()

CompanionSetCollection & CompanionSetCollection::operator= ( const CompanionSetCollection &  )

delete

ToString()

std::string CompanionSetCollection::ToString

(

)

const

For trace and debugging.

Member Data Documentation

m_table_num_to_companion_set

std::array<CompanionSet *, MAX_TABLES> CompanionSetCollection::m_table_num_to_companion_set {nullptr}

private

A mapping from table number to CompanionSet.

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The documentation for this class was generated from the following files:

• sql/join_optimizer/relational_expression.h
• sql/join_optimizer/relational_expression.cc