Semijoin_mat_optimize Struct Reference

#include <table.h>

Collaboration diagram for Semijoin_mat_optimize:

Public Attributes
struct st_position *	positions
	Optimal join order calculated for inner tables of this semijoin op.
bool	lookup_allowed
	True if data types allow the MaterializeLookup semijoin strategy.
bool	scan_allowed
	True if data types allow the MaterializeScan semijoin strategy.
double	expected_rowcount
	Expected #rows in the materialized table.
Cost_estimate	materialization_cost
	Materialization cost - execute sub-join and write rows to temp.table.
Cost_estimate	lookup_cost
	Cost to make one lookup in the temptable.
Cost_estimate	scan_cost
	Cost of scanning the materialized table.
Item_field **	mat_fields
	Array of pointers to fields in the materialized table.

Detailed Description

Semijoin_mat_optimize collects data used when calculating the cost of executing a semijoin operation using a materialization strategy. It is used during optimization phase only.

Definition at line 2183 of file table.h.

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

• sql/table.h