Class to store all the Master_info objects of a slave to access them in the replication code base or performance schema replication tables. More...

#include <rpl_msr.h>

Public Member Functions
	Multisource_info ()

	~Multisource_info ()

bool	add_mi (const char channel_name, Master_info mi)
	Adds the Master_info object to both replication_channel_map and rpl_pfs_mi. More...

Master_info *	get_mi (const char *channel_name)
	Find the master_info object corresponding to a channel explicitly from replication channel_map; Return if it exists, otherwise return 0. More...

Master_info *	get_default_channel_mi ()
	Return the master_info object corresponding to the default channel. More...

bool	delete_mi (const char *channel_name)
	Remove the entry corresponding to the channel, from the replication_channel_map and sets index in the multisource_mi to 0; And also delete the {mi, rli} pair corresponding to this channel. More...

const char *	get_default_channel ()
	Get the default channel for this multisourced_slave;. More...

size_t	get_num_instances (bool all=false)
	Get the number of instances of Master_info in the map. More...

size_t	get_number_of_connection_auto_failover_channels_running ()
	Get the number of running channels which have asynchronous replication failover feature, i.e. More...

uint	get_max_channels ()
	Get max channels allowed for this map. More...

bool	is_valid_channel_count ()
	Returns true if the current number of channels in this slave is less than the MAX_CHANNLES. More...

bool	is_group_replication_channel_name (const char *channel, bool is_applier=false)
	Returns if a channel name is one of the reserved group replication names. More...

mi_map::iterator	begin (enum_channel_type channel_type=SLAVE_REPLICATION_CHANNEL)
	Forward iterators to initiate traversing of a map. More...

mi_map::iterator	end (enum_channel_type channel_type=SLAVE_REPLICATION_CHANNEL)

Master_info *	get_mi_at_pos (uint pos)
	Used only by replication performance schema indices to get the master_info at the position 'pos' from the rpl_pfs_mi array. More...

void	rdlock ()
	Acquire the read lock. More...

int	tryrdlock ()
	Try to acquire a read lock, return 0 if the read lock is held, otherwise an error will be returned. More...

void	wrlock ()
	Acquire the write lock. More...

int	trywrlock ()
	Try to acquire a write lock, return 0 if the write lock is held, otherwise an error will be returned. More...

void	unlock ()
	Release the lock (whether it is a write or read lock). More...

void	assert_some_lock () const
	Assert that some thread holds either the read or the write lock. More...

void	assert_some_wrlock () const
	Assert that some thread holds the write lock. More...

Private Member Functions
void	init_rpl_pfs_mi ()

bool	add_mi_to_rpl_pfs_mi (Master_info *mi)
	Add a master info pointer to the rpl_pfs_mi array at the first NULL;. More...

int	get_index_from_rpl_pfs_mi (const char *channel_name)
	Get the index of the master info corresponding to channel name from the rpl_pfs_mi array. More...

Private Attributes
replication_channel_map	rep_channel_map

uint	current_mi_count

Master_info *	default_channel_mi

Checkable_rwlock *	m_channel_map_lock
	This lock was designed to protect the channel_map from adding or removing master_info objects from the map (adding or removing replication channels). More...

Master_info *	rpl_pfs_mi [MAX_CHANNELS]

mi_map	empty_mi_map

Static Private Attributes
static const unsigned int	MAX_CHANNELS = 256

static const char *	default_channel = ""
	Default_channel for this instance, currently is predefined and cannot be modified. More...

static const char *	group_replication_channel_names []

Detailed Description

Class to store all the Master_info objects of a slave to access them in the replication code base or performance schema replication tables.

In a Multisourced replication setup, a slave connects to several masters (also called as sources). This class stores the Master_infos where each Master_info belongs to a slave.

The important objects for a slave are the following: i) Master_info and Relay_log_info (replica_parallel_workers == 0) ii) Master_info, Relay_log_info and Slave_worker(replica_parallel_workers >0 )

Master_info is always associated with a Relay_log_info per channel. So, it is enough to store Master_infos and call the corresponding Relay_log_info by mi->rli;

This class is not yet thread safe. Any part of replication code that calls this class member function should always lock the channel_map.

Only a single global object for a server instance should be created.

The two important data structures in this class are i) C++ std map to store the Master_info pointers with channel name as a key. These are the base channel maps.

ii) C++ std map to store the channel maps with a channel type as its key. This map stores slave channel maps, group replication channels or others iii) An array of Master_info pointers to access from performance schema tables. This array is specifically implemented in a way to make a) pfs indices simple i.e a simple integer counter b) To avoid recalibration of data structure if master info is deleted. Consider the following high level implementation of a pfs table to make a row.

highlevel_pfs_funciton()
{
 while(replication_table_xxxx.rnd_next())
 {
   do stuff;
 }
}

However, we lock channel_map lock for every rnd_next(); There is a gap where an addition/deletion of a channel would rearrange the map making the integer indices of the pfs table point to a wrong value. Either missing a row or duplicating a row.

We solve this problem, by using an array exclusively to use in replciation pfs tables, by marking a master_info defeated as 0 (i.e NULL). A new master info is added to this array at the first NULL always.

Constructor & Destructor Documentation

◆ Multisource_info()

Multisource_info::Multisource_info ( )

inline

◆ ~Multisource_info()

Multisource_info::~Multisource_info ( )

inline

Member Function Documentation

◆ add_mi()

bool Multisource_info::add_mi	(	const char *	channel_name,
		Master_info *	mi
	)

Adds the Master_info object to both replication_channel_map and rpl_pfs_mi.

Parameters

[in]	channel_name	channel name
[in]	mi	pointer to master info corresponding to this channel

Return values

false	successfully added
true	couldn't add channel

◆ add_mi_to_rpl_pfs_mi()

bool Multisource_info::add_mi_to_rpl_pfs_mi ( Master_info * mi )

private

Add a master info pointer to the rpl_pfs_mi array at the first NULL;.

Parameters

[in] mi master info object to be added.

Returns: false if success.Else true.

◆ assert_some_lock()

void Multisource_info::assert_some_lock ( ) const

inline

Assert that some thread holds either the read or the write lock.

◆ assert_some_wrlock()

void Multisource_info::assert_some_wrlock ( ) const

inline

Assert that some thread holds the write lock.

◆ begin()

mi_map::iterator Multisource_info::begin ( enum_channel_type channel_type = SLAVE_REPLICATION_CHANNEL )

inline

Forward iterators to initiate traversing of a map.

◆ delete_mi()

bool Multisource_info::delete_mi ( const char * channel_name )

Remove the entry corresponding to the channel, from the replication_channel_map and sets index in the multisource_mi to 0; And also delete the {mi, rli} pair corresponding to this channel.

Note: this requires the caller to hold the mi->channel_wrlock. If the method succeeds the master info object is deleted and the lock is released. If the an error occurs and the method return true, the {mi} object won't be deleted and the caller should release the channel_wrlock.

Parameters

[in] channel_name Name of the channel for a Master_info object which must exist.

Returns: true if an error occurred, false otherwise

◆ end()

mi_map::iterator Multisource_info::end ( enum_channel_type channel_type = SLAVE_REPLICATION_CHANNEL )

inline

◆ get_default_channel()

const char * Multisource_info::get_default_channel ( )

inline

Get the default channel for this multisourced_slave;.

◆ get_default_channel_mi()

Master_info * Multisource_info::get_default_channel_mi ( )

inline

Return the master_info object corresponding to the default channel.

Return values

pointer to the master info object if exists. Otherwise, NULL;

◆ get_index_from_rpl_pfs_mi()

int Multisource_info::get_index_from_rpl_pfs_mi ( const char * channel_name )

private

Get the index of the master info corresponding to channel name from the rpl_pfs_mi array.

Parameters

[in] channel_name Channel name to get the index from

Returns: index of mi for the channel_name. Else -1;

◆ get_max_channels()

uint Multisource_info::get_max_channels ( )

inline

Get max channels allowed for this map.

◆ get_mi()

Master_info * Multisource_info::get_mi ( const char * channel_name )

Find the master_info object corresponding to a channel explicitly from replication channel_map; Return if it exists, otherwise return 0.

Parameters

[in] channel_name channel name for the master info object.

Returns: pointer to the master info object if exists in the map. Otherwise, NULL;

◆ get_mi_at_pos()

Master_info * Multisource_info::get_mi_at_pos ( uint pos )

Used only by replication performance schema indices to get the master_info at the position 'pos' from the rpl_pfs_mi array.

Parameters

[in] pos the index in the rpl_pfs_mi array

Return values

pointer to the master info object at pos 'pos';

◆ get_num_instances()

size_t Multisource_info::get_num_instances ( bool all = false )

inline

Get the number of instances of Master_info in the map.

Parameters

all	If it should count all channels. If false, only slave channels are counted.

Returns: The number of channels or 0 if empty.

◆ get_number_of_connection_auto_failover_channels_running()

size_t Multisource_info::get_number_of_connection_auto_failover_channels_running ( )

inline

Get the number of running channels which have asynchronous replication failover feature, i.e.

CHANGE MASTER TO option SOURCE_CONNECTION_AUTO_FAILOVER, enabled.

Returns: The number of channels.

◆ init_rpl_pfs_mi()

void Multisource_info::init_rpl_pfs_mi ( )

inlineprivate

◆ is_group_replication_channel_name()

bool Multisource_info::is_group_replication_channel_name	(	const char *	channel,
		bool	is_applier = `false`
	)

Returns if a channel name is one of the reserved group replication names.

Parameters

channel	the channel name to test
is_applier	compare only with applier name

Return values

true	the name is a reserved name
false	non reserved name

◆ is_valid_channel_count()

bool Multisource_info::is_valid_channel_count ( )

inline

Returns true if the current number of channels in this slave is less than the MAX_CHANNLES.

◆ rdlock()

void Multisource_info::rdlock ( )

inline

Acquire the read lock.

◆ tryrdlock()

int Multisource_info::tryrdlock ( )

inline

Try to acquire a read lock, return 0 if the read lock is held, otherwise an error will be returned.

Returns: 0 in case of success, or 1 otherwise.

◆ trywrlock()

int Multisource_info::trywrlock ( )

inline

Try to acquire a write lock, return 0 if the write lock is held, otherwise an error will be returned.

Returns: 0 in case of success, or 1 otherwise.

◆ unlock()

void Multisource_info::unlock ( )

inline

Release the lock (whether it is a write or read lock).

◆ wrlock()

void Multisource_info::wrlock ( )

inline

Acquire the write lock.

Member Data Documentation

◆ current_mi_count

uint Multisource_info::current_mi_count

private

◆ default_channel

const char * Multisource_info::default_channel = ""

staticprivate

Default_channel for this instance, currently is predefined and cannot be modified.

◆ default_channel_mi

Master_info* Multisource_info::default_channel_mi

private

◆ empty_mi_map

mi_map Multisource_info::empty_mi_map

private

◆ group_replication_channel_names

const char * Multisource_info::group_replication_channel_names

staticprivate

Initial value:

= {

"group_replication_applier", "group_replication_recovery"}

◆ m_channel_map_lock

Checkable_rwlock* Multisource_info::m_channel_map_lock

private

This lock was designed to protect the channel_map from adding or removing master_info objects from the map (adding or removing replication channels).

In fact it also acts like the LOCK_active_mi of MySQL 5.6, preventing two replication administrative commands to run in parallel.

◆ MAX_CHANNELS

const unsigned int Multisource_info::MAX_CHANNELS = 256

staticprivate

◆ rep_channel_map

replication_channel_map Multisource_info::rep_channel_map

private

◆ rpl_pfs_mi

Master_info* Multisource_info::rpl_pfs_mi[MAX_CHANNELS]

private

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

sql/rpl_msr.h
sql/rpl_msr.cc

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Multisource_info()

◆ ~Multisource_info()

Member Function Documentation

◆ add_mi()

◆ add_mi_to_rpl_pfs_mi()

◆ assert_some_lock()

◆ assert_some_wrlock()

◆ begin()

◆ delete_mi()

◆ end()

◆ get_default_channel()

◆ get_default_channel_mi()

◆ get_index_from_rpl_pfs_mi()

◆ get_max_channels()

◆ get_mi()

◆ get_mi_at_pos()

◆ get_num_instances()

◆ get_number_of_connection_auto_failover_channels_running()

◆ init_rpl_pfs_mi()

◆ is_group_replication_channel_name()

◆ is_valid_channel_count()

◆ rdlock()

◆ tryrdlock()

◆ trywrlock()

◆ unlock()

◆ wrlock()

Member Data Documentation

◆ current_mi_count

◆ default_channel

◆ default_channel_mi

◆ empty_mi_map

◆ group_replication_channel_names

◆ m_channel_map_lock

◆ MAX_CHANNELS

◆ rep_channel_map

◆ rpl_pfs_mi