Server_cost_constants Class Reference

Cost constants for operations done by the server. More...

#include <opt_costconstants.h>

Public Member Functions
	Server_cost_constants ()
	Creates a server cost constants object using the default values defined in this class. More...
double	row_evaluate_cost () const
	Cost for evaluating the query condition on a row. More...
double	key_compare_cost () const
	Cost for comparing two keys. More...
double	memory_temptable_create_cost () const
	Cost for creating an internal temporary table in memory. More...
double	memory_temptable_row_cost () const
	Cost for retrieving or storing a row in an internal temporary table stored in memory. More...
double	disk_temptable_create_cost () const
	Cost for creating an internal temporary table in a disk resident storage engine. More...
double	disk_temptable_row_cost () const
	Cost for retrieving or storing a row in an internal disk resident temporary table. More...
cost_constant_error	set (const LEX_CSTRING &name, const double value)
	Set the value of one of the cost constants. More...

Private Attributes
double	m_row_evaluate_cost
	Cost for evaluating the query condition on a row. More...
double	m_key_compare_cost
	Cost for comparing two keys. More...
double	m_memory_temptable_create_cost
	Cost for creating an internal temporary table in memory. More...
double	m_memory_temptable_row_cost
	Cost for retrieving or storing a row in an internal temporary table stored in memory. More...
double	m_disk_temptable_create_cost
	Cost for creating an internal temporary table in a disk resident storage engine. More...
double	m_disk_temptable_row_cost
	Cost for retrieving or storing a row in an internal disk resident temporary table. More...

Static Private Attributes
static const double	ROW_EVALUATE_COST = 0.1
	Default cost for evaluation of the query condition for a row. More...
static const double	KEY_COMPARE_COST = 0.05
	Default cost for comparing row ids. More...
static const double	MEMORY_TEMPTABLE_CREATE_COST = 1.0
	Cost for creating a memory temporary table. More...
static const double	MEMORY_TEMPTABLE_ROW_COST = 0.1
	Cost for inserting or reading a row in a memory temporary table. More...
static const double	DISK_TEMPTABLE_CREATE_COST = 20.0
	Cost for creating a disk temporary table. More...
static const double	DISK_TEMPTABLE_ROW_COST = 0.5
	Cost for inserting or reading a row in a disk temporary table. More...

Detailed Description

Cost constants for operations done by the server.

Constructor & Destructor Documentation

Server_cost_constants()

Server_cost_constants::Server_cost_constants ( )

inline

Creates a server cost constants object using the default values defined in this class.

Member Function Documentation

disk_temptable_create_cost()

double Server_cost_constants::disk_temptable_create_cost ( ) const

inline

Cost for creating an internal temporary table in a disk resident storage engine.

disk_temptable_row_cost()

double Server_cost_constants::disk_temptable_row_cost ( ) const

inline

Cost for retrieving or storing a row in an internal disk resident temporary table.

key_compare_cost()

double Server_cost_constants::key_compare_cost ( ) const

inline

Cost for comparing two keys.

memory_temptable_create_cost()

double Server_cost_constants::memory_temptable_create_cost ( ) const

inline

Cost for creating an internal temporary table in memory.

memory_temptable_row_cost()

double Server_cost_constants::memory_temptable_row_cost ( ) const

inline

Cost for retrieving or storing a row in an internal temporary table stored in memory.

row_evaluate_cost()

double Server_cost_constants::row_evaluate_cost ( ) const

inline

Cost for evaluating the query condition on a row.

set()

cost_constant_error Server_cost_constants::set	(	const LEX_CSTRING &	name,
		const double	value
	)

Set the value of one of the cost constants.

Parameters

name	name of cost constant
value	new value

Returns

Status for updating the cost constant

Member Data Documentation

DISK_TEMPTABLE_CREATE_COST

const double Server_cost_constants::DISK_TEMPTABLE_CREATE_COST = 20.0

staticprivate

Cost for creating a disk temporary table.

DISK_TEMPTABLE_ROW_COST

const double Server_cost_constants::DISK_TEMPTABLE_ROW_COST = 0.5

staticprivate

Cost for inserting or reading a row in a disk temporary table.

KEY_COMPARE_COST

const double Server_cost_constants::KEY_COMPARE_COST = 0.05

staticprivate

Default cost for comparing row ids.

m_disk_temptable_create_cost

double Server_cost_constants::m_disk_temptable_create_cost

private

Cost for creating an internal temporary table in a disk resident storage engine.

m_disk_temptable_row_cost

double Server_cost_constants::m_disk_temptable_row_cost

private

Cost for retrieving or storing a row in an internal disk resident temporary table.

m_key_compare_cost

double Server_cost_constants::m_key_compare_cost

private

Cost for comparing two keys.

m_memory_temptable_create_cost

double Server_cost_constants::m_memory_temptable_create_cost

private

Cost for creating an internal temporary table in memory.

m_memory_temptable_row_cost

double Server_cost_constants::m_memory_temptable_row_cost

private

Cost for retrieving or storing a row in an internal temporary table stored in memory.

m_row_evaluate_cost

double Server_cost_constants::m_row_evaluate_cost

private

Cost for evaluating the query condition on a row.

MEMORY_TEMPTABLE_CREATE_COST

const double Server_cost_constants::MEMORY_TEMPTABLE_CREATE_COST = 1.0

staticprivate

Cost for creating a memory temporary table.

MEMORY_TEMPTABLE_ROW_COST

const double Server_cost_constants::MEMORY_TEMPTABLE_ROW_COST = 0.1

staticprivate

Cost for inserting or reading a row in a memory temporary table.

ROW_EVALUATE_COST

const double Server_cost_constants::ROW_EVALUATE_COST = 0.1

staticprivate

Default cost for evaluation of the query condition for a row.

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

• sql/opt_costconstants.h
• sql/opt_costconstants.cc