DynamicRangeIterator Class Reference

#include <ref_row_iterators.h>

Inheritance diagram for DynamicRangeIterator:

Public Member Functions
	DynamicRangeIterator (THD *thd, TABLE *table, QEP_TAB *qep_tab, ha_rows *examined_rows)
	~DynamicRangeIterator () 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
QEP_TAB *	m_qep_tab
MEM_ROOT	m_mem_root
unique_ptr_destroy_only< RowIterator >	m_iterator
bool	m_quick_traced_before = false
	Used by optimizer tracing to decide whether or not dynamic range analysis of this select has been traced already. More...
ha_rows *const	m_examined_rows
MY_BITMAP *	m_read_set_without_base_columns
	Read set to be used when range optimizer picks covering index. More...
MY_BITMAP	m_read_set_with_base_columns
	Read set to be used when range optimizer picks a non-covering index or when table scan gets picked. More...

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

Constructor & Destructor Documentation

DynamicRangeIterator()

DynamicRangeIterator::DynamicRangeIterator	(	THD *	thd,
		TABLE *	table,
		QEP_TAB *	qep_tab,
		ha_rows *	examined_rows
	)

~DynamicRangeIterator()

DynamicRangeIterator::~DynamicRangeIterator ( )

override

Member Function Documentation

Init()

bool DynamicRangeIterator::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()

int DynamicRangeIterator::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

ha_rows* const DynamicRangeIterator::m_examined_rows

private

m_iterator

unique_ptr_destroy_only<RowIterator> DynamicRangeIterator::m_iterator

private

m_mem_root

MEM_ROOT DynamicRangeIterator::m_mem_root

private

m_qep_tab

QEP_TAB* DynamicRangeIterator::m_qep_tab

private

m_quick_traced_before

bool DynamicRangeIterator::m_quick_traced_before = false

private

Used by optimizer tracing to decide whether or not dynamic range analysis of this select has been traced already.

If optimizer trace option DYNAMIC_RANGE is enabled, range analysis will be traced with different ranges for every record to the left of this table in the join. If disabled, range analysis will only be traced for the first range.

m_read_set_with_base_columns

MY_BITMAP DynamicRangeIterator::m_read_set_with_base_columns

private

Read set to be used when range optimizer picks a non-covering index or when table scan gets picked.

It is setup by adding base columns to the read set setup by filter_gcol_for_dynamic_range_scan(). add_virtual_gcol_base_cols() adds the base columns when initializing this iterator.

m_read_set_without_base_columns

MY_BITMAP* DynamicRangeIterator::m_read_set_without_base_columns

private

Read set to be used when range optimizer picks covering index.

This read set is same as what filter_gcol_for_dynamic_range_scan() sets up after filtering out the base columns for virtually generated columns from the original table read set. By filtering out the base columns, it avoids addition of unneeded columns for hash join/BKA.

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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