cost_model.h File Reference

#include "my_base.h"
#include "sql/join_optimizer/access_path.h"
#include "sql/join_optimizer/relational_expression.h"
#include "sql/mem_root_array.h"

Go to the source code of this file.

Classes
struct	FilterCost
	See EstimateFilterCost. More...

Functions
void	AddCost (THD *thd, const ContainedSubquery &subquery, double num_rows, FilterCost *cost)
	Used internally by EstimateFilterCost() only. More...
FilterCost	EstimateFilterCost (THD *thd, double num_rows, Item *condition, Query_block *outer_query_block)
	Estimate the cost of evaluating “condition”, “num_rows” times. More...
FilterCost	EstimateFilterCost (THD *thd, double num_rows, const Mem_root_array< ContainedSubquery > &contained_subqueries)
	A cheaper overload of EstimateFilterCost() that assumes that all contained subqueries have already been extracted (ie., it skips the walking, which can be fairly expensive). More...
double	EstimateCostForRefAccess (THD *thd, TABLE *table, unsigned key_idx, double num_output_rows)
void	EstimateSortCost (AccessPath *path, ha_rows limit_rows=HA_POS_ERROR)
void	EstimateMaterializeCost (THD *thd, AccessPath *path)
void	EstimateAggregateCost (AccessPath *path, const Query_block *query_block)
void	EstimateDeleteRowsCost (AccessPath *path)
double	FindOutputRowsForJoin (double left_rows, double right_rows, const JoinPredicate *edge)

Variables
constexpr double	kApplyOneFilterCost = 0.1
constexpr double	kAggregateOneRowCost = 0.1
constexpr double	kSortOneRowCost = 0.1
constexpr double	kHashBuildOneRowCost = 0.1
constexpr double	kHashProbeOneRowCost = 0.1
constexpr double	kHashReturnOneRowCost = 0.07
constexpr double	kMaterializeOneRowCost = 0.1
constexpr double	kWindowOneRowCost = 0.1

Function Documentation

AddCost()

void AddCost	(	THD *	thd,
		const ContainedSubquery &	subquery,
		double	num_rows,
		FilterCost *	cost
	)

Used internally by EstimateFilterCost() only.

EstimateAggregateCost()

void EstimateAggregateCost	(	AccessPath *	path,
		const Query_block *	query_block
	)

EstimateCostForRefAccess()

double EstimateCostForRefAccess	(	THD *	thd,
		TABLE *	table,
		unsigned	key_idx,
		double	num_output_rows
	)

EstimateDeleteRowsCost()

void EstimateDeleteRowsCost

(

AccessPath *

path

)

EstimateFilterCost() [1/2]

FilterCost EstimateFilterCost ( THD *  thd, double  num_rows, const Mem_root_array< ContainedSubquery > &  contained_subqueries  )

inline

A cheaper overload of EstimateFilterCost() that assumes that all contained subqueries have already been extracted (ie., it skips the walking, which can be fairly expensive).

This data is typically computed by FindContainedSubqueries().

EstimateFilterCost() [2/2]

FilterCost EstimateFilterCost	(	THD *	thd,
		double	num_rows,
		Item *	condition,
		Query_block *	outer_query_block
	)

Estimate the cost of evaluating “condition”, “num_rows” times.

This is a fairly rudimentary estimation, but it includes the cost of any subqueries that may be present and that need evaluation.

EstimateMaterializeCost()

void EstimateMaterializeCost	(	THD *	thd,
		AccessPath *	path
	)

EstimateSortCost()

void EstimateSortCost	(	AccessPath *	path,
		ha_rows	limit_rows = HA_POS_ERROR
	)

FindOutputRowsForJoin()

double FindOutputRowsForJoin ( double  left_rows, double  right_rows, const JoinPredicate *  edge  )

inline

Variable Documentation

kAggregateOneRowCost

constexpr double kAggregateOneRowCost = 0.1

constexpr

kApplyOneFilterCost

constexpr double kApplyOneFilterCost = 0.1

constexpr

kHashBuildOneRowCost

constexpr double kHashBuildOneRowCost = 0.1

constexpr

kHashProbeOneRowCost

constexpr double kHashProbeOneRowCost = 0.1

constexpr

kHashReturnOneRowCost

constexpr double kHashReturnOneRowCost = 0.07

constexpr

kMaterializeOneRowCost

constexpr double kMaterializeOneRowCost = 0.1

constexpr

kSortOneRowCost

constexpr double kSortOneRowCost = 0.1

constexpr

kWindowOneRowCost

constexpr double kWindowOneRowCost = 0.1

constexpr