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Public Attributes
Semijoin_mat_optimize Struct Reference

#include <table.h>

List of all members.

Public Attributes

struct st_positionpositions
 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.

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