Keep track of MDL_ticket for different durations. More...

#include <mdl.h>

Classes
struct	Duration

struct	Hash

struct	Key_equal

struct	MDL_ticket_handle
	Utility struct for representing a ticket pointer and its duration. More...

Public Types
using	List_iterator = Ticket_p_list::Iterator
	Public alias. More...

Public Member Functions
	MDL_ticket_store ()
	Constructs store. More...

template<typename CLOS >
void	for_each_ticket_in_duration_list (enum_mdl_duration dur, CLOS &&clos)
	Calls the closure provided as argument for each of the MDL_tickets in the given duration. More...

template<typename CLOS >
void	for_each_ticket_in_ticket_lists (CLOS &&clos)
	Calls the closure provided as argument for each of the MDL_tickets in the store. More...

bool	is_empty () const
	Predicate for the emptiness of the store. More...

bool	is_empty (int di) const
	Predicate for the emptiness of a given duration list. More...

MDL_ticket *	front (int di)
	Return the first MDL_ticket for the given duration. More...

void	push_front (enum_mdl_duration dur, MDL_ticket *ticket)
	Push a ticket onto the list for a given duration. More...

void	remove (enum_mdl_duration dur, MDL_ticket *ticket)
	Remove a ticket from a duration list. More...

List_iterator	list_iterator (int di) const
	Return a P-list iterator to the given duration. More...

void	move_all_to_explicit_duration ()
	Move all tickets to the explicit duration list. More...

void	move_explicit_to_transaction_duration ()
	Move all tickets to the transaction duration list. More...

MDL_ticket_handle	find (const MDL_request &req) const
	Look up a ticket based on its MDL_key. More...

void	set_materialized ()
	Mark boundary for tickets with fast_path=false, so that later calls to materialize_fast_path_locks() do not have to traverse the whole set of tickets. More...

MDL_ticket *	materialized_front (int di)
	Return the first ticket for which materialize_fast_path_locks already has been called for the given duration. More...

Private Types
using	Ticket_p_list = I_P_List< MDL_ticket, I_P_List_adapter< MDL_ticket, &MDL_ticket::next_in_context, &MDL_ticket::prev_in_context > >

using	Ticket_map = std::unordered_multimap< const MDL_key *, MDL_ticket_handle, Hash, Key_equal >

Private Member Functions
MDL_ticket_handle	find_in_lists (const MDL_request &req) const

MDL_ticket_handle	find_in_hash (const MDL_request &req) const

Private Attributes
Duration	m_durations [MDL_DURATION_END]

const size_t	THRESHOLD = 256
	If the number of tickets in the ticket store (in all durations) is equal to, or exceeds this constant the hash index (in the form of an unordered_multi_map) will be maintained and used for lookups. More...

const size_t	INITIAL_BUCKET_COUNT = THRESHOLD * 2
	Initial number of buckets in the hash index. More...

size_t	m_count = 0

std::unique_ptr< Ticket_map >	m_map

Detailed Description

Keep track of MDL_ticket for different durations.

Maintains a hash-based secondary index into the linked lists, to speed up access by MDL_key.

Member Typedef Documentation

◆ List_iterator

using MDL_ticket_store::List_iterator = Ticket_p_list::Iterator

Public alias.

◆ Ticket_map

using MDL_ticket_store::Ticket_map = std::unordered_multimap<const MDL_key *, MDL_ticket_handle, Hash, Key_equal>

private

◆ Ticket_p_list

using MDL_ticket_store::Ticket_p_list = I_P_List<MDL_ticket, I_P_List_adapter<MDL_ticket, &MDL_ticket::next_in_context, &MDL_ticket::prev_in_context> >

private

Constructor & Destructor Documentation

◆ MDL_ticket_store()

MDL_ticket_store::MDL_ticket_store ( )

inline

Constructs store.

The hash index is initially empty. Filled on demand.

Member Function Documentation

◆ find()

MDL_ticket_store::MDL_ticket_handle MDL_ticket_store::find ( const MDL_request & req ) const

Look up a ticket based on its MDL_key.

Parameters

req	request to locate ticket for

Returns: MDL_ticket_handle with ticket pointer and found duration (or nullptr and MDL_DURATION_END if not found

NDEBUG

◆ find_in_hash()

MDL_ticket_store::MDL_ticket_handle MDL_ticket_store::find_in_hash ( const MDL_request & req ) const

private

◆ find_in_lists()

MDL_ticket_store::MDL_ticket_handle MDL_ticket_store::find_in_lists ( const MDL_request & req ) const

private

◆ for_each_ticket_in_duration_list()

template<typename CLOS >

void MDL_ticket_store::for_each_ticket_in_duration_list	(	enum_mdl_duration	dur,
		CLOS &&	clos
	)

inline

Calls the closure provided as argument for each of the MDL_tickets in the given duration.

Parameters

dur	duration list to iterate over
clos	closure to invoke for each ticket in the list

◆ for_each_ticket_in_ticket_lists()

template<typename CLOS >

void MDL_ticket_store::for_each_ticket_in_ticket_lists ( CLOS && clos )

inline

Calls the closure provided as argument for each of the MDL_tickets in the store.

Parameters

clos	closure to invoke for each ticket in the store

◆ front()

MDL_ticket * MDL_ticket_store::front ( int di )

Return the first MDL_ticket for the given duration.

Parameters

di	duration to get first ticket for

Returns: first ticket in the given duration or nullptr if no such tickets exist

◆ is_empty() [1/2]

bool MDL_ticket_store::is_empty ( ) const

Predicate for the emptiness of the store.

Returns: true if there are no tickets in the store

◆ is_empty() [2/2]

bool MDL_ticket_store::is_empty ( int di ) const

Predicate for the emptiness of a given duration list.

Parameters

di	the duration to check

Returns: true if there are no tickets with the given duration

◆ list_iterator()

List_iterator MDL_ticket_store::list_iterator ( int di ) const

inline

Return a P-list iterator to the given duration.

Parameters

di	duration list index

Returns: P-list iterator to tickets with given duration

◆ materialized_front()

MDL_ticket * MDL_ticket_store::materialized_front ( int di )

Return the first ticket for which materialize_fast_path_locks already has been called for the given duration.

Parameters

di	duration list index

Returns: first materialized ticket for the given duration

◆ move_all_to_explicit_duration()

void MDL_ticket_store::move_all_to_explicit_duration ( )

Move all tickets to the explicit duration list.

◆ move_explicit_to_transaction_duration()

void MDL_ticket_store::move_explicit_to_transaction_duration ( )

Move all tickets to the transaction duration list.

◆ push_front()

void MDL_ticket_store::push_front	(	enum_mdl_duration	dur,
		MDL_ticket *	ticket
	)

Push a ticket onto the list for a given duration.

Parameters

dur	duration list to push into
ticket	to push

◆ remove()

void MDL_ticket_store::remove	(	enum_mdl_duration	dur,
		MDL_ticket *	ticket
	)

Remove a ticket from a duration list.

Note that since the underlying list is an intrusive linked list there is no guarantee that the ticket is actually in the duration list. It will be removed from which ever list it is in.

◆ set_materialized()

void MDL_ticket_store::set_materialized ( )

Mark boundary for tickets with fast_path=false, so that later calls to materialize_fast_path_locks() do not have to traverse the whole set of tickets.

Member Data Documentation

◆ INITIAL_BUCKET_COUNT

const size_t MDL_ticket_store::INITIAL_BUCKET_COUNT = THRESHOLD * 2

private

Initial number of buckets in the hash index.

THRESHOLD is chosen to get a fill-factor of 50% when reaching the threshold value.

◆ m_count

size_t MDL_ticket_store::m_count = 0

private

◆ m_durations

Duration MDL_ticket_store::m_durations[MDL_DURATION_END]

private

◆ m_map

std::unique_ptr<Ticket_map> MDL_ticket_store::m_map

private

◆ THRESHOLD

const size_t MDL_ticket_store::THRESHOLD = 256

private

If the number of tickets in the ticket store (in all durations) is equal to, or exceeds this constant the hash index (in the form of an unordered_multi_map) will be maintained and used for lookups.

The value 256 is chosen as it has worked well in benchmarks.

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

sql/mdl.h
sql/mdl.cc

Classes

Public Types

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ List_iterator

◆ Ticket_map

◆ Ticket_p_list

Constructor & Destructor Documentation

◆ MDL_ticket_store()

Member Function Documentation

◆ find()

◆ find_in_hash()

◆ find_in_lists()

◆ for_each_ticket_in_duration_list()

◆ for_each_ticket_in_ticket_lists()

◆ front()

◆ is_empty() [1/2]

◆ is_empty() [2/2]

◆ list_iterator()

◆ materialized_front()

◆ move_all_to_explicit_duration()

◆ move_explicit_to_transaction_duration()

◆ push_front()

◆ remove()

◆ set_materialized()

Member Data Documentation

◆ INITIAL_BUCKET_COUNT

◆ m_count

◆ m_durations

◆ m_map

◆ THRESHOLD