Aggregates unsorted data into a temporary table, using update operations to keep running aggregates. More...

Inheritance diagram for TemptableAggregateIterator< Profiler >:

Public Member Functions
	TemptableAggregateIterator (THD thd, unique_ptr_destroy_only< RowIterator > subquery_iterator, Temp_table_param temp_table_param, TABLE table, unique_ptr_destroy_only< RowIterator > table_iterator, JOIN join, int ref_slice)

bool	Init () override
	Initialize or reinitialize the iterator. More...

int	Read () override
	Read a single row. 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	EndPSIBatchModeIfStarted () override
	Ends performance schema batch mode, if started. More...

void	UnlockRow () override

const IteratorProfiler *	GetProfiler () const override
	Get profiling data for this iterator (for 'EXPLAIN ANALYZE'). More...

const Profiler *	GetTableIterProfiler () const

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 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 Member Functions
bool	using_hash_key () const

bool	move_table_to_disk (int error, bool was_insert)
	Move the in-memory temporary table to disk. More...

Private Attributes
unique_ptr_destroy_only< RowIterator >	m_subquery_iterator
	The iterator we are reading rows from. More...

unique_ptr_destroy_only< RowIterator >	m_table_iterator
	The iterator used to scan the resulting temporary table. More...

Temp_table_param *	m_temp_table_param

JOIN *const	m_join

const int	m_ref_slice

Profiler	m_profiler
	Profiling data for this iterator. More...

Profiler	m_table_iter_profiler
	Profiling data for m_table_iterator,. 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

Detailed Description

template<typename Profiler>
class TemptableAggregateIterator< Profiler >

Aggregates unsorted data into a temporary table, using update operations to keep running aggregates.

After that, works as a MaterializeIterator in that it allows the temporary table to be scanned.

'Profiler' should be 'IteratorProfilerImpl' for 'EXPLAIN ANALYZE' and 'DummyIteratorProfiler' otherwise. It is implemented as a a template parameter to minimize the impact this probe has on normal query execution.

Constructor & Destructor Documentation

◆ TemptableAggregateIterator()

template<typename Profiler >

TemptableAggregateIterator< Profiler >::TemptableAggregateIterator	(	THD *	thd,
		unique_ptr_destroy_only< RowIterator >	subquery_iterator,
		Temp_table_param *	temp_table_param,
		TABLE *	table,
		unique_ptr_destroy_only< RowIterator >	table_iterator,
		JOIN *	join,
		int	ref_slice
	)

Member Function Documentation

◆ EndPSIBatchModeIfStarted()

template<typename Profiler >

void TemptableAggregateIterator< Profiler >::EndPSIBatchModeIfStarted ( )

inlineoverridevirtual

Ends performance schema batch mode, if started.

It's always safe to call this.

Iterators that have children (composite iterators) must forward the EndPSIBatchModeIfStarted() call to every iterator they could conceivably have called StartPSIBatchMode() on. This ensures that after such a call to on the root iterator, all handlers are out of batch mode.

Reimplemented from RowIterator.

◆ GetProfiler()

template<typename Profiler >

const IteratorProfiler * TemptableAggregateIterator< Profiler >::GetProfiler ( ) const

inlineoverridevirtual

Get profiling data for this iterator (for 'EXPLAIN ANALYZE').

Valid for TimingIterator, MaterializeIterator and TemptableAggregateIterator only.

Reimplemented from RowIterator.

◆ GetTableIterProfiler()

template<typename Profiler >

const Profiler * TemptableAggregateIterator< Profiler >::GetTableIterProfiler ( ) const

inline

◆ Init()

template<typename Profiler >

bool TemptableAggregateIterator< Profiler >::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.

◆ move_table_to_disk()

template<typename Profiler >

bool TemptableAggregateIterator< Profiler >::move_table_to_disk	(	int	error_code,
		bool	was_insert
	)

private

Move the in-memory temporary table to disk.

Parameters

[in]	error_code	The error code because of which the table is being moved to disk.
[in]	was_insert	True, if the table is moved to disk during an insert operation.

Returns: true if error.

◆ Read()

template<typename Profiler >

int TemptableAggregateIterator< Profiler >::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.

◆ SetNullRowFlag()

template<typename Profiler >

void TemptableAggregateIterator< Profiler >::SetNullRowFlag ( bool is_null_row )

inlineoverridevirtual

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).

This is used for outer joins, when an iterator hasn't produced any rows and we need to produce a NULL-complemented row. Init() or Read() won't necessarily reset this flag, so if you ever set is to true, make sure to also set it to false when needed.

Note that this can be called without Init() having been called first. For example, NestedLoopIterator can hit EOF immediately on the outer iterator, which means the inner iterator doesn't get an Init() call, but will still forward SetNullRowFlag to both inner and outer iterators.

TODO: We shouldn't need this. See the comments on AggregateIterator for a bit more discussion on abstracting out a row interface.

Implements RowIterator.

◆ UnlockRow()

template<typename Profiler >

void TemptableAggregateIterator< Profiler >::UnlockRow ( )

inlineoverridevirtual

Implements RowIterator.

◆ using_hash_key()

template<typename Profiler >

bool TemptableAggregateIterator< Profiler >::using_hash_key ( ) const

inlineprivate

Member Data Documentation

◆ m_join

template<typename Profiler >

JOIN* const TemptableAggregateIterator< Profiler >::m_join

private

◆ m_profiler

template<typename Profiler >

Profiler TemptableAggregateIterator< Profiler >::m_profiler

private

Profiling data for this iterator.

Used for 'EXPLAIN ANALYZE'.

See also: MaterializeIterator::m_profiler for a description of how this is used.

◆ m_ref_slice

template<typename Profiler >

const int TemptableAggregateIterator< Profiler >::m_ref_slice

private

◆ m_subquery_iterator

template<typename Profiler >

unique_ptr_destroy_only<RowIterator> TemptableAggregateIterator< Profiler >::m_subquery_iterator

private

The iterator we are reading rows from.

◆ m_table_iter_profiler

template<typename Profiler >

Profiler TemptableAggregateIterator< Profiler >::m_table_iter_profiler

private

Profiling data for m_table_iterator,.

See also: MaterializeIterator::m_table_iter_profiler.

◆ m_table_iterator

template<typename Profiler >

unique_ptr_destroy_only<RowIterator> TemptableAggregateIterator< Profiler >::m_table_iterator

private

The iterator used to scan the resulting temporary table.

◆ m_temp_table_param

template<typename Profiler >

Temp_table_param* TemptableAggregateIterator< Profiler >::m_temp_table_param

private

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

sql/iterators/composite_iterators.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ TemptableAggregateIterator()

Member Function Documentation

◆ EndPSIBatchModeIfStarted()

◆ GetProfiler()

◆ GetTableIterProfiler()

◆ Init()

◆ move_table_to_disk()

◆ Read()

◆ SetNullRowFlag()

◆ UnlockRow()

◆ using_hash_key()

Member Data Documentation

◆ m_join

◆ m_profiler

◆ m_ref_slice

◆ m_subquery_iterator

◆ m_table_iter_profiler

◆ m_table_iterator

◆ m_temp_table_param