Certifier_broadcast_thread Class Reference

This class is a core component of the database state machine replication protocol. More...

#include <certifier.h>

Public Member Functions
	Certifier_broadcast_thread ()
	Certifier_broadcast_thread constructor. More...
virtual	~Certifier_broadcast_thread ()
int	initialize ()
	Initialize broadcast thread. More...
int	terminate ()
	Terminate broadcast thread. More...
void	dispatcher ()
	Broadcast thread worker method. More...

Static Public Attributes
static const int	BROADCAST_GTID_EXECUTED_PERIOD = 60
	Period (in seconds) between stable transactions set broadcast. More...

Private Member Functions
int	broadcast_gtid_executed ()
	Broadcast local GTID_EXECUTED to group. More...

Private Attributes
bool	aborted
	Thread control. More...
THD *	broadcast_thd
my_thread_handle	broadcast_pthd
mysql_mutex_t	broadcast_run_lock
mysql_cond_t	broadcast_run_cond
mysql_mutex_t	broadcast_dispatcher_lock
mysql_cond_t	broadcast_dispatcher_cond
thread_state	broadcast_thd_state
size_t	broadcast_counter
int	broadcast_gtid_executed_period

Detailed Description

This class is a core component of the database state machine replication protocol.

It implements conflict detection based on a certification procedure.

Snapshot Isolation is based on assigning logical timestamp to optimistic transactions, i.e. the ones which successfully meet certification and are good to commit on all members in the group. This timestamp is a monotonically increasing counter, and is same across all members in the group.

This timestamp, which in our algorithm is the snapshot version, is further used to update the certification info. The snapshot version maps the items in a transaction to the GTID_EXECUTED that this transaction saw when it was executed, that is, on which version the transaction was executed.

If the incoming transaction snapshot version is a subset of a previous certified transaction for the same write set, the current transaction was executed on top of outdated data, so it will be negatively certified. Otherwise, this transaction is marked certified and goes into applier.

Constructor & Destructor Documentation

Certifier_broadcast_thread()

Certifier_broadcast_thread::Certifier_broadcast_thread

(

)

Certifier_broadcast_thread constructor.

~Certifier_broadcast_thread()

Certifier_broadcast_thread::~Certifier_broadcast_thread ( )

virtual

Member Function Documentation

broadcast_gtid_executed()

int Certifier_broadcast_thread::broadcast_gtid_executed ( )

private

Broadcast local GTID_EXECUTED to group.

Returns

the operation status

Return values

0	OK
!=0	Error

dispatcher()

void Certifier_broadcast_thread::dispatcher

(

)

Broadcast thread worker method.

initialize()

int Certifier_broadcast_thread::initialize

(

)

Initialize broadcast thread.

Returns

the operation status

Return values

0	OK
!=0	Error

terminate()

int Certifier_broadcast_thread::terminate

(

)

Terminate broadcast thread.

Returns

the operation status

Return values

0	OK
!=0	Error

Member Data Documentation

aborted

bool Certifier_broadcast_thread::aborted

private

Thread control.

broadcast_counter

size_t Certifier_broadcast_thread::broadcast_counter

private

broadcast_dispatcher_cond

mysql_cond_t Certifier_broadcast_thread::broadcast_dispatcher_cond

private

broadcast_dispatcher_lock

mysql_mutex_t Certifier_broadcast_thread::broadcast_dispatcher_lock

private

BROADCAST_GTID_EXECUTED_PERIOD

const int Certifier_broadcast_thread::BROADCAST_GTID_EXECUTED_PERIOD = 60

static

Period (in seconds) between stable transactions set broadcast.

broadcast_gtid_executed_period

int Certifier_broadcast_thread::broadcast_gtid_executed_period

private

broadcast_pthd

my_thread_handle Certifier_broadcast_thread::broadcast_pthd

private

broadcast_run_cond

mysql_cond_t Certifier_broadcast_thread::broadcast_run_cond

private

broadcast_run_lock

mysql_mutex_t Certifier_broadcast_thread::broadcast_run_lock

private

broadcast_thd

THD* Certifier_broadcast_thread::broadcast_thd

private

broadcast_thd_state

thread_state Certifier_broadcast_thread::broadcast_thd_state

private

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

• plugin/group_replication/include/certifier.h
• plugin/group_replication/src/certifier.cc