RefIterator< Reverse > Class Template Reference

For each record on the left side of a join (given in Init()), returns one or more matching rows from the given table, i.e., WHERE column=<ref>. More...

#include <ref_row_iterators.h>

Inheritance diagram for RefIterator< Reverse >:

Public Member Functions
	RefIterator (THD *thd, TABLE *table, Index_lookup *ref, bool use_order, double expected_rows, ha_rows *examined_rows)
	~RefIterator () override
bool	Init () override
	Initialize or reinitialize the iterator. More...
int	Read () override
	Read a single row. More...
Public Member Functions inherited from TableRowIterator
	TableRowIterator (THD *thd, TABLE *table)
void	UnlockRow () override
	The default implementation of unlock-row method of RowIterator, used in all access methods except EQRefIterator. More...
void	SetNullRowFlag (bool is_null_row) override
	Mark the current row buffer as containing a NULL row or not, so that if you read from it and the flag is true, you'll get only NULLs no matter what is actually in the buffer (typically some old leftover row). More...
void	StartPSIBatchMode () override
	Start performance schema batch mode, if supported (otherwise ignored). More...
void	EndPSIBatchModeIfStarted () override
	Ends performance schema batch mode, if started. More...
Public Member Functions inherited from RowIterator
	RowIterator (THD *thd)
virtual	~RowIterator ()=default
	RowIterator (const RowIterator &)=delete
	RowIterator (RowIterator &&)=default
virtual const IteratorProfiler *	GetProfiler () const
	Get profiling data for this iterator (for 'EXPLAIN ANALYZE'). More...
virtual void	SetOverrideProfiler ([[maybe_unused]] const IteratorProfiler *profiler)
virtual RowIterator *	real_iterator ()
	If this iterator is wrapping a different iterator (e.g. More...
virtual const RowIterator *	real_iterator () const

Private Attributes
Index_lookup *const	m_ref
const bool	m_use_order
const double	m_expected_rows
ha_rows *const	m_examined_rows
bool	m_first_record_since_init
bool	m_is_mvi_unique_filter_enabled

Additional Inherited Members
Protected Member Functions inherited from TableRowIterator
int	HandleError (int error)
void	PrintError (int error)
TABLE *	table () const
Protected Member Functions inherited from RowIterator
THD *	thd () const

Detailed Description

template<bool Reverse>
class RefIterator< Reverse >

For each record on the left side of a join (given in Init()), returns one or more matching rows from the given table, i.e., WHERE column=<ref>.

Constructor & Destructor Documentation

RefIterator()

template<bool Reverse>

RefIterator< Reverse >::RefIterator ( THD *  thd, TABLE *  table, Index_lookup *  ref, bool  use_order, double  expected_rows, ha_rows *  examined_rows  )

inline

~RefIterator()

template<bool Reverse>

RefIterator< Reverse >::~RefIterator ( )

override

Member Function Documentation

Init()

template<bool Reverse>

bool RefIterator< Reverse >::Init ( )

overridevirtual

Initialize or reinitialize the iterator.

You must always call Init() before trying a Read() (but Init() does not imply Read()).

You can call Init() multiple times; subsequent calls will rewind the iterator (or reposition it, depending on whether the iterator takes in e.g. a Index_lookup) and allow you to read the records anew.

Implements RowIterator.

Read()

template<bool Reverse>

int RefIterator< Reverse >::Read ( )

overridevirtual

Read a single row.

The row data is not actually returned from the function; it is put in the table's (or tables', in case of a join) record buffer, ie., table->records[0].

Return values

0	OK
-1	End of records
1	Error

Implements RowIterator.

Member Data Documentation

m_examined_rows

template<bool Reverse>

ha_rows* const RefIterator< Reverse >::m_examined_rows

private

m_expected_rows

template<bool Reverse>

const double RefIterator< Reverse >::m_expected_rows

private

m_first_record_since_init

template<bool Reverse>

bool RefIterator< Reverse >::m_first_record_since_init

private

m_is_mvi_unique_filter_enabled

template<bool Reverse>

bool RefIterator< Reverse >::m_is_mvi_unique_filter_enabled

private

m_ref

template<bool Reverse>

Index_lookup* const RefIterator< Reverse >::m_ref

private

m_use_order

template<bool Reverse>

const bool RefIterator< Reverse >::m_use_order

private

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The documentation for this class was generated from the following files:

• sql/iterators/ref_row_iterators.h
• sql/iterators/ref_row_iterators.cc