Delegate Class Reference

Base class for adding replication event observer infra-structure. More...

#include <rpl_handler.h>

Inheritance diagram for Delegate:

Public Types
typedef List< Observer_info >	Observer_info_list
typedef List_iterator< Observer_info >	Observer_info_iterator

Public Member Functions
	Delegate (PSI_rwlock_key key)
	Class constructor. More...
virtual	~Delegate ()
	Class destructor. More...
int	add_observer (void *observer, st_plugin_int *plugin)
	Adds an observer to the observer list. More...
int	remove_observer (void *observer)
	Removes an observer from the observer list. More...
Observer_info_iterator	observer_info_iter ()
	Retrieves an iterator for the observer list. More...
bool	is_empty ()
	Returns whether or not there are registered observers. More...
int	read_lock ()
	Acquires this Delegate class instance lock in read/shared mode. More...
int	write_lock ()
	Acquires this Delegate class instance lock in write/exclusive mode. More...
int	unlock ()
	Releases this Delegate class instance lock. More...
bool	is_inited ()
	Returns whether or not this instance was initialized. More...
void	update_lock_type ()
	Toggles the type of lock between a classical read-write lock and a shared-exclusive spin-lock. More...
void	update_plugin_ref_count ()
	Increases the info->plugin usage reference counting if replication_optimize_for_static_plugin_config is being enabled, in order to prevent plugin removal. More...
bool	use_rw_lock_type ()
	Returns whether or not to use the classic read-write lock. More...
bool	use_spin_lock_type ()
	Returns whether or not to use the shared spin-lock. More...

Private Types
enum	enum_delegate_lock_type { DELEGATE_OS_LOCK = -1 , DELEGATE_SPIN_LOCK = 1 }
enum	enum_delegate_lock_mode { DELEGATE_LOCK_MODE_SHARED = 0 , DELEGATE_LOCK_MODE_EXCLUSIVE = 1 }

Private Member Functions
void	acquire_plugin_ref_count (Observer_info *info)
	Increases the info->plugin reference counting and stores that reference internally. More...
void	lock_it (enum_delegate_lock_mode mode)
	Locks the active lock (OS read-write lock or shared spin-lock) according to the mode passed on as a parameter. More...

Private Attributes
Observer_info_list	observer_info_list
	List of registered observers. More...
mysql_rwlock_t	lock
	A read/write lock to be used when not optimizing for static plugin config. More...
lock::Shared_spin_lock	m_spin_lock
	A shared-exclusive spin lock to be used when optimizing for static plugin config. More...
MEM_ROOT	memroot {key_memory_delegate, 1024}
	Memory pool to be used to allocate the observers list. More...
bool	inited
	Flag statign whether or not this instance was initialized. More...
std::atomic< int >	m_configured_lock_type
	The type of lock configured to be used, either a classic read-write (-1) lock or a shared-exclusive spin lock (1). More...
std::atomic< int >	m_acquired_locks
	The count of locks acquired: -1 will be added for each classic read-write lock acquisitions; +1 will be added for each shared-exclusive spin lock acquisition. More...
std::map< plugin_ref, size_t >	m_acquired_references
	List of acquired plugin references, to be held while replication_optimize_for_static_plugin_config option is enabled. More...

Detailed Description

Base class for adding replication event observer infra-structure.

It's meant to be sub-classed by classes that will provide the support for the specific event types. This class is meant just to provide basic support for managing observers and managing resource access and lock acquisition.

Member Typedef Documentation

Observer_info_iterator

typedef List_iterator<Observer_info> Delegate::Observer_info_iterator

Observer_info_list

typedef List<Observer_info> Delegate::Observer_info_list

Member Enumeration Documentation

enum_delegate_lock_mode

enum Delegate::enum_delegate_lock_mode

private

Enumerator
DELEGATE_LOCK_MODE_SHARED
DELEGATE_LOCK_MODE_EXCLUSIVE

enum_delegate_lock_type

enum Delegate::enum_delegate_lock_type

private

Enumerator
DELEGATE_OS_LOCK
DELEGATE_SPIN_LOCK

Constructor & Destructor Documentation

Delegate()

Delegate::Delegate ( PSI_rwlock_key  key )

explicit

Class constructor.

Parameters

key	the PFS key for instrumenting the class lock

~Delegate()

Delegate::~Delegate ( )

virtual

Class destructor.

Member Function Documentation

acquire_plugin_ref_count()

void Delegate::acquire_plugin_ref_count ( Observer_info *  info )

private

Increases the info->plugin reference counting and stores that reference internally.

add_observer()

int Delegate::add_observer	(	void *	observer,
		st_plugin_int *	plugin
	)

Adds an observer to the observer list.

Parameters

observer	The observer object to be added to the list
plugin	The plugin the observer is being loaded from

Returns

0 upon success, 1 otherwise

is_empty()

bool Delegate::is_empty

(

)

Returns whether or not there are registered observers.

Returns

whether or not there are registered observers

is_inited()

bool Delegate::is_inited

(

)

Returns whether or not this instance was initialized.

Returns

whether or not this instance was initialized

lock_it()

void Delegate::lock_it ( enum_delegate_lock_mode  mode )

private

Locks the active lock (OS read-write lock or shared spin-lock) according to the mode passed on as a parameter.

Parameters

mode	The mode to lock in, either DELEGATE_LOCK_MODE_SHARED or DELEGATE_LOCK_MODE_EXCLUSIVE.

observer_info_iter()

Delegate::Observer_info_iterator Delegate::observer_info_iter

(

)

Retrieves an iterator for the observer list.

Returns

the iterator for the observer list

read_lock()

int Delegate::read_lock

(

)

Acquires this Delegate class instance lock in read/shared mode.

Returns

0 upon success, 1 otherwise

remove_observer()

int Delegate::remove_observer

(

void *

observer

)

Removes an observer from the observer list.

Parameters

observer

The observer object to be added to the list

Returns

0 upon success, 1 otherwise

unlock()

int Delegate::unlock

(

)

Releases this Delegate class instance lock.

Returns

0 upon success, 1 otherwise

update_lock_type()

void Delegate::update_lock_type

(

)

Toggles the type of lock between a classical read-write lock and a shared-exclusive spin-lock.

update_plugin_ref_count()

void Delegate::update_plugin_ref_count

(

)

Increases the info->plugin usage reference counting if replication_optimize_for_static_plugin_config is being enabled, in order to prevent plugin removal.

Decreases the info->plugin usage reference counting if replication_optimize_for_static_plugin_config is being disabled, in order to allow plugin removal.

use_rw_lock_type()

bool Delegate::use_rw_lock_type

(

)

Returns whether or not to use the classic read-write lock.

The read-write lock should be used if that type of lock is already acquired by some thread or if the server is not optimized for static plugin configuration.

Returns

true if one should use the classic read-write lock, false otherwise

use_spin_lock_type()

bool Delegate::use_spin_lock_type

(

)

Returns whether or not to use the shared spin-lock.

The shared spin-lock should be used if that type of lock is already acquired by some thread or if the server is optimized for static plugin configuration.

Returns

true if one should use the shared spin-lock, false otherwise

write_lock()

int Delegate::write_lock

(

)

Acquires this Delegate class instance lock in write/exclusive mode.

Returns

0 upon success, 1 otherwise

Member Data Documentation

inited

bool Delegate::inited

private

Flag statign whether or not this instance was initialized.

lock

mysql_rwlock_t Delegate::lock

private

A read/write lock to be used when not optimizing for static plugin config.

m_acquired_locks

std::atomic<int> Delegate::m_acquired_locks

private

The count of locks acquired: -1 will be added for each classic read-write lock acquisitions; +1 will be added for each shared-exclusive spin lock acquisition.

m_acquired_references

std::map<plugin_ref, size_t> Delegate::m_acquired_references

private

List of acquired plugin references, to be held while replication_optimize_for_static_plugin_config option is enabled.

If the option is disabled, the references in this list will be released.

m_configured_lock_type

std::atomic<int> Delegate::m_configured_lock_type

private

The type of lock configured to be used, either a classic read-write (-1) lock or a shared-exclusive spin lock (1).

m_spin_lock

lock::Shared_spin_lock Delegate::m_spin_lock

private

A shared-exclusive spin lock to be used when optimizing for static plugin config.

memroot

MEM_ROOT Delegate::memroot {key_memory_delegate, 1024}

private

Memory pool to be used to allocate the observers list.

observer_info_list

Observer_info_list Delegate::observer_info_list

private

List of registered observers.

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

• sql/rpl_handler.h
• sql/rpl_handler.cc