MaterializePathParameters Struct Reference

#include <materialize_path_parameters.h>

Classes
struct	Operand

Public Types
enum	DedupType : uint8_t { DEDUP_FOR_DISTINCT , DEDUP_FOR_GROUP_BY , NO_DEDUP }
	The context for which deduplication is being used. More...

Public Attributes
Mem_root_array< Operand >	m_operands
Mem_root_array< const AccessPath * > *	invalidators
TABLE *	table
	Handle to table to materialize into. More...
Common_table_expr *	cte
	If materializing a CTE, points to it (see m_cte), otherwise nullptr. More...
Query_expression *	unit
	The query expression we are materializing. More...
int	ref_slice
bool	rematerialize
	True if rematerializing on every Init() call (e.g., because we have a dependency on a value from outside the query block). More...
ha_rows	limit_rows
	Used for when pushing LIMIT down to MaterializeIterator; this is more efficient than having a LimitOffsetIterator above the MaterializeIterator, since we can stop materializing when there are enough rows. More...
bool	reject_multiple_rows
	True if this is the top level iterator for a materialized derived table transformed from a scalar subquery which needs run-time cardinality check. More...
DedupType	deduplication_reason {NO_DEDUP}

Member Enumeration Documentation

DedupType

enum MaterializePathParameters::DedupType : uint8_t

The context for which deduplication is being used.

Note: this deduplication is different than the deduplication for UNION which is handled separately, not through this enum.

Enumerator
DEDUP_FOR_DISTINCT
DEDUP_FOR_GROUP_BY
NO_DEDUP

Member Data Documentation

cte

Common_table_expr* MaterializePathParameters::cte

If materializing a CTE, points to it (see m_cte), otherwise nullptr.

deduplication_reason

DedupType MaterializePathParameters::deduplication_reason {NO_DEDUP}

invalidators

Mem_root_array<const AccessPath *>* MaterializePathParameters::invalidators

limit_rows

ha_rows MaterializePathParameters::limit_rows

Used for when pushing LIMIT down to MaterializeIterator; this is more efficient than having a LimitOffsetIterator above the MaterializeIterator, since we can stop materializing when there are enough rows.

(This is especially important for recursive CTEs.) Note that we cannot have a LimitOffsetIterator below the MaterializeIterator, as that would count wrong if we have deduplication, and would not work at all for recursive CTEs. Set to HA_POS_ERROR for no limit.

m_operands

Mem_root_array<Operand> MaterializePathParameters::m_operands

ref_slice

int MaterializePathParameters::ref_slice

See also

JOIN. If we are materializing across JOINs, e.g. derived tables, ref_slice should be left at -1.

reject_multiple_rows

bool MaterializePathParameters::reject_multiple_rows

True if this is the top level iterator for a materialized derived table transformed from a scalar subquery which needs run-time cardinality check.

rematerialize

bool MaterializePathParameters::rematerialize

True if rematerializing on every Init() call (e.g., because we have a dependency on a value from outside the query block).

table

TABLE* MaterializePathParameters::table

Handle to table to materialize into.

unit

Query_expression* MaterializePathParameters::unit

The query expression we are materializing.

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

• sql/join_optimizer/materialize_path_parameters.h