MySQL 8.4.3
Source Code Documentation
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Semijoin_mat_optimize collects data used when calculating the cost of executing a semijoin operation using a materialization strategy. More...
#include <nested_join.h>
Public Attributes | |
POSITION * | positions {nullptr} |
Optimal join order calculated for inner tables of this semijoin op. More... | |
bool | lookup_allowed {false} |
True if data types allow the MaterializeLookup semijoin strategy. More... | |
bool | scan_allowed {false} |
True if data types allow the MaterializeScan semijoin strategy. More... | |
double | expected_rowcount {0.0} |
Expected number of rows in the materialized table. More... | |
Cost_estimate | materialization_cost |
Materialization cost - execute sub-join and write rows to temp.table. More... | |
Cost_estimate | lookup_cost |
Cost to make one lookup in the temptable. More... | |
Cost_estimate | scan_cost |
Cost of scanning the materialized table. More... | |
Item_field ** | mat_fields {nullptr} |
Array of pointers to fields in the materialized table. More... | |
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.
double Semijoin_mat_optimize::expected_rowcount {0.0} |
Expected number of rows in the materialized table.
bool Semijoin_mat_optimize::lookup_allowed {false} |
True if data types allow the MaterializeLookup semijoin strategy.
Cost_estimate Semijoin_mat_optimize::lookup_cost |
Cost to make one lookup in the temptable.
Item_field** Semijoin_mat_optimize::mat_fields {nullptr} |
Array of pointers to fields in the materialized table.
Cost_estimate Semijoin_mat_optimize::materialization_cost |
Materialization cost - execute sub-join and write rows to temp.table.
Optimal join order calculated for inner tables of this semijoin op.
bool Semijoin_mat_optimize::scan_allowed {false} |
True if data types allow the MaterializeScan semijoin strategy.
Cost_estimate Semijoin_mat_optimize::scan_cost |
Cost of scanning the materialized table.