MySQL 8.3.0
Source Code Documentation
FilterCost Struct Reference

See EstimateFilterCost. More...

#include <cost_model.h>

Public Attributes

double cost_if_not_materialized {0.0}
 Cost of evaluating the filter for all rows if subqueries are not materialized. More...
 
double init_cost_if_not_materialized {0.0}
 Initial cost before the filter can be applied for the first time. More...
 
double cost_if_materialized {0.0}
 Cost of evaluating the filter for all rows if all subqueries in it have been materialized beforehand. More...
 
double cost_to_materialize {0.0}
 Cost of materializing all subqueries present in the filter. More...
 

Detailed Description

See EstimateFilterCost.

Member Data Documentation

◆ cost_if_materialized

double FilterCost::cost_if_materialized {0.0}

Cost of evaluating the filter for all rows if all subqueries in it have been materialized beforehand.

If there are no subqueries in the condition, equals cost_if_not_materialized.

◆ cost_if_not_materialized

double FilterCost::cost_if_not_materialized {0.0}

Cost of evaluating the filter for all rows if subqueries are not materialized.

(Note that this includes the contribution from init_cost_if_not_materialized.)

◆ cost_to_materialize

double FilterCost::cost_to_materialize {0.0}

Cost of materializing all subqueries present in the filter.

If there are no subqueries in the condition, equals zero.

◆ init_cost_if_not_materialized

double FilterCost::init_cost_if_not_materialized {0.0}

Initial cost before the filter can be applied for the first time.

Typically the cost of executing 'independent subquery' in queries like: "SELECT * FROM tab WHERE field = <independent subquery>". (That corresponds to the Item_singlerow_subselect class.)


The documentation for this struct was generated from the following file: