The group action class to do migration to primary mode or elect a primary. More...

#include <primary_election_action.h>

Inheritance diagram for Primary_election_action:

Public Types
enum	enum_action_execution_mode { PRIMARY_ELECTION_ACTION_PRIMARY_SWITCH = 0 , PRIMARY_ELECTION_ACTION_MODE_SWITCH = 1 , PRIMARY_ELECTION_ACTION_END = 2 }
	Enum for type of primary election executed. More...

enum	enum_primary_election_phase { PRIMARY_NO_PHASE = 0 , PRIMARY_VALIDATION_PHASE = 1 , PRIMARY_SAFETY_CHECK_PHASE = 2 , PRIMARY_ELECTION_PHASE = 3 , PRIMARY_ELECTED_PHASE = 4 }
	Enum for the phases on the primary action. More...

enum	enum_primary_election_status { PRIMARY_ELECTION_INIT = 0 , PRIMARY_ELECTION_END_ELECTION = 1 , PRIMARY_ELECTION_END_ERROR = 2 }
	Enum for the phases on the primary action. More...

Public Types inherited from Group_action
enum	enum_action_execution_result { GROUP_ACTION_RESULT_TERMINATED = 0 , GROUP_ACTION_RESULT_ERROR = 1 , GROUP_ACTION_RESULT_RESTART = 2 , GROUP_ACTION_RESULT_ABORTED = 3 , GROUP_ACTION_RESULT_KILLED = 4 , GROUP_ACTION_RESULT_END = 5 }
	Enum for the end results of a action execution. More...

Public Member Functions
	Primary_election_action ()
	Create a new primary election action. More...

	Primary_election_action (std::string primary_uuid, my_thread_id thread_id, int32 transaction_wait_timeout=-1)
	Create a new primary election action with a given uuid. More...

	~Primary_election_action () override

void	get_action_message (Group_action_message **message) override
	Get the message with parameters to this action. More...

int	process_action_message (Group_action_message &message, const std::string &message_origin) override

Group_action::enum_action_execution_result	execute_action (bool invoking_member, Plugin_stage_monitor_handler stage_handler, Notification_context ) override
	Execute the action. More...

bool	stop_action_execution (bool killed) override

Group_action_diagnostics *	get_execution_info () override
	Gets the info about execution, be it success or failure. More...

PSI_stage_key	get_action_stage_termination_key () override
	For this action, what is the PSI key for the last stage when the action is terminating. More...

Public Member Functions inherited from Group_action
virtual	~Group_action ()=0

Private Member Functions
bool	persist_variable_values ()
	Persist the value of the variables changed in the action. More...

void	log_result_execution (bool error, bool aborted, bool mode_changed, std::string &error_message)
	Log the result of the execution. More...

int	after_view_change (const std::vector< Gcs_member_identifier > &joining, const std::vector< Gcs_member_identifier > &leaving, const std::vector< Gcs_member_identifier > &group, bool is_leaving, bool skip_election, enum_primary_election_mode election_mode, std::string &suggested_primary) override
	Executed after view install and before primary election. More...

int	after_primary_election (std::string primary_uuid, enum_primary_election_primary_change_status primary_change_status, enum_primary_election_mode election_mode, int error) override
	Executed after primary election. More...

int	before_message_handling (const Plugin_gcs_message &message, const std::string &message_origin, bool *skip_message) override
	Executed before the message is processed. More...

bool	stop_transaction_monitor_thread ()
	Stop the transaction_monitor_thread if running. More...

void	change_action_phase (enum_primary_election_phase phase)
	Changes the phase where the action is currently. More...

Private Member Functions inherited from Group_event_observer
virtual	~Group_event_observer ()=0

Private Attributes
enum_action_execution_mode	action_execution_mode
	Is this an primary change or mode change. More...

enum_primary_election_phase	current_action_phase
	The current phase. More...

mysql_mutex_t	phase_lock
	Lock for the phase change. More...

bool	single_election_action_aborted
	Is this action aborted. More...

bool	error_on_primary_election
	Was there an error in the election. More...

bool	action_killed
	Was this action order to terminate by a kill signal. More...

std::string	appointed_primary_uuid
	The primary to elect. More...

std::string	appointed_primary_gcs_id
	The id of the primary to elect. More...

std::string	invoking_member_gcs_id
	The id of the invoking primary. More...

std::string	old_primary_uuid
	The uuid of the original master at action invocation. More...

bool	is_primary
	If this member is old primary. More...

my_thread_id	invoking_thread_id
	The thread that invoked this action - if applicable, 0 otherwise. More...

bool	is_primary_election_invoked
	Is the primary election invoked. More...

enum_primary_election_status	m_execution_status {PRIMARY_ELECTION_INIT}
	primary election status More...

bool	is_transaction_queue_applied
	Is the transaction back log consumed. More...

mysql_mutex_t	notification_lock
	The lock for notifications. More...

mysql_cond_t	notification_cond
	The condition for notifications. More...

Primary_election_validation_handler	validation_handler
	The handler for primary election validations. More...

Group_action_diagnostics	execution_message_area
	Place to store result messages. More...

int32	m_transaction_wait_timeout = {-1}
	The number of seconds to wait before setting the THD::KILL_CONNECTION flag for the transactions that did not reach commit stage. More...

Transaction_monitor_thread *	transaction_monitor_thread {nullptr}
	Used to monitor transactions, this stops the new transactions and sets the THD::KILL_CONNECTION flag for the transactions that did not reach commit stage post timeout expire. More...

Detailed Description

The group action class to do migration to primary mode or elect a primary.

Member Enumeration Documentation

◆ enum_action_execution_mode

enum Primary_election_action::enum_action_execution_mode

Enum for type of primary election executed.

Enumerator
PRIMARY_ELECTION_ACTION_PRIMARY_SWITCH
PRIMARY_ELECTION_ACTION_MODE_SWITCH
PRIMARY_ELECTION_ACTION_END

◆ enum_primary_election_phase

enum Primary_election_action::enum_primary_election_phase

Enum for the phases on the primary action.

Enumerator
PRIMARY_NO_PHASE
PRIMARY_VALIDATION_PHASE
PRIMARY_SAFETY_CHECK_PHASE
PRIMARY_ELECTION_PHASE
PRIMARY_ELECTED_PHASE

◆ enum_primary_election_status

enum Primary_election_action::enum_primary_election_status

Enum for the phases on the primary action.

Enumerator
PRIMARY_ELECTION_INIT
PRIMARY_ELECTION_END_ELECTION
PRIMARY_ELECTION_END_ERROR

Constructor & Destructor Documentation

◆ Primary_election_action() [1/2]

Primary_election_action::Primary_election_action ( )

Create a new primary election action.

◆ Primary_election_action() [2/2]

Primary_election_action::Primary_election_action	(	std::string	primary_uuid,
		my_thread_id	thread_id,
		int32	transaction_wait_timeout = `-1`
	)

Create a new primary election action with a given uuid.

Parameters

primary_uuid	the primary uuid to elect, can be empty
thread_id	the local thread id that is invoking this action
transaction_wait_timeout	The number of seconds to wait before setting the THD::KILL_CONNECTION flag for the transactions that did not reach commit stage.

◆ ~Primary_election_action()

Primary_election_action::~Primary_election_action ( )

override

Assert has been used since object has not been destroyed at the exit point code. If this ever occurs, the scenario needs to be analyzed to understand why object was not deleted on the exit points of the primary election.

delete transaction_monitor_thread is present at exit points when a change of primary is finishing. However if delete is not triggered at those exit points then object should be destroyed here. This code is added for safety.

Member Function Documentation

◆ after_primary_election()

int Primary_election_action::after_primary_election	(	std::string	primary_uuid,
		enum_primary_election_primary_change_status	primary_change_status,
		enum_primary_election_mode	election_mode,
		int	error
	)

overrideprivatevirtual

Executed after primary election.

Parameters

primary_uuid	the elected primary
primary_change_status	if the primary changed after the election
election_mode	what was the election mode
error	if there was and error on the process

Implements Group_event_observer.

◆ after_view_change()

int Primary_election_action::after_view_change	(	const std::vector< Gcs_member_identifier > &	joining,
		const std::vector< Gcs_member_identifier > &	leaving,
		const std::vector< Gcs_member_identifier > &	group,
		bool	is_leaving,
		bool *	skip_election,
		enum_primary_election_mode *	election_mode,
		std::string &	suggested_primary
	)

overrideprivatevirtual

Executed after view install and before primary election.

Parameters

	joining	members joining the group
	leaving	members leaving the group
	group	members in the group
	is_leaving	is the member leaving
[out]	skip_election	skip primary election on view
[out]	election_mode	election mode
[out]	suggested_primary	what should be the next primary to elect

Either: -This is a change from SP and the the old primary died, so there is no invoking member, nor a member that is waiting on local transactions. -On changes from multi primary, and the invoking member left

For all the old secondaries that remain this means:

If election was already called, then we don't care
If election was not yet called then, either 2.1 we are still validating the appointed primary, so we just change what the invoking member is 2.2 we have already validate it, so if this is the new invoker it must invoke the new primary election

Note that this state change from validation to the next state is not in a group logical moment so different members can be at different stages. Still all that members care is the moment the election is called, so the result will be the same at all members. If the primary is not valid, the stage never changed from validation so member will invoke the election here. If valid, members will either update the invoking member or invoke the election according to the stage (hence the phase lock)

We also make the failover primary election process to be skipped, because we want a specific primary to be elected.

There is an election and the primary being elected dies.

Case 1: We are moving to another primary, and it failed. The process will fail abort but we still try to invoke an election to go back to the old primary.

Case 2: We are moving to single primary mode and the appointed primary died, then we move to another primary and emit a warning

Note 1: We pass election params instead of invoking them because of the hook mechanism that is invoking this method and is also used in the invoked election methods.

Check if we can change to the old primary. If this variable is empty, it is not present.

Implements Group_event_observer.

◆ before_message_handling()

int Primary_election_action::before_message_handling	(	const Plugin_gcs_message &	message,
		const std::string &	message_origin,
		bool *	skip_message
	)

overrideprivatevirtual

Executed before the message is processed.

Parameters

	message	The GCS message
	message_origin	The member that sent this message (address)
[out]	skip_message	skip message handling if true

Implements Group_event_observer.

◆ change_action_phase()

void Primary_election_action::change_action_phase ( enum_primary_election_phase phase )

private

Changes the phase where the action is currently.

Parameters

phase the new election primary execution phase

◆ execute_action()

Group_action::enum_action_execution_result Primary_election_action::execute_action	(	bool	invoking_member,
		Plugin_stage_monitor_handler *	stage_handler,
		Notification_context *
	)

overridevirtual

Execute the action.

Parameters

invoking_member	is the member that invoked it
stage_handler	the stage handler to report progress

Returns: the execution result

Observers have been de-registered so transaction_monitor_thread should have been destroyed by now in after_view_change or after_primary_election. If not, then destroy the object now(during UDF failure it has been observed intermittently object was not destroyed in after_view_change or after_primary_election).

Implements Group_action.

◆ get_action_message()

void Primary_election_action::get_action_message ( Group_action_message ** message )

overridevirtual

Get the message with parameters to this action.

Parameters

[out] message the message to start the action

Implements Group_action.

◆ get_action_stage_termination_key()

PSI_stage_key Primary_election_action::get_action_stage_termination_key ( )

overridevirtual

For this action, what is the PSI key for the last stage when the action is terminating.

Returns: The stage key for this class

Reimplemented from Group_action.

◆ get_execution_info()

Group_action_diagnostics * Primary_election_action::get_execution_info ( )

overridevirtual

Gets the info about execution, be it success or failure.

Returns: the execution diagnostics object that was the message and its level

Implements Group_action.

◆ log_result_execution()

void Primary_election_action::log_result_execution	(	bool	error,
		bool	aborted,
		bool	mode_changed,
		std::string &	error_message
	)

private

Log the result of the execution.

Parameters

error	Did an error occurred
aborted	was the action aborted?
mode_changed	was the mode changed to single primary?
error_message	details of error

◆ persist_variable_values()

bool Primary_election_action::persist_variable_values ( )

private

Persist the value of the variables changed in the action.

Returns: true if a problem was found, false otherwise

◆ process_action_message()

int Primary_election_action::process_action_message	(	Group_action_message &	message,
		const std::string &	message_origin
	)

overridevirtual

Implements Group_action.

◆ stop_action_execution()

bool Primary_election_action::stop_action_execution ( bool killed )

overridevirtual

When a UDF group_replication_set_as_primary is killed using 'KILL connection_id' code reaches here.

Implements Group_action.

◆ stop_transaction_monitor_thread()

bool Primary_election_action::stop_transaction_monitor_thread ( )

private

Stop the transaction_monitor_thread if running.

Returns: status

Return values

true	failed to stop the thread
false	thread stopped successfully.

Member Data Documentation

◆ action_execution_mode

enum_action_execution_mode Primary_election_action::action_execution_mode

private

Is this an primary change or mode change.

◆ action_killed

bool Primary_election_action::action_killed

private

Was this action order to terminate by a kill signal.

◆ appointed_primary_gcs_id

std::string Primary_election_action::appointed_primary_gcs_id

private

The id of the primary to elect.

◆ appointed_primary_uuid

std::string Primary_election_action::appointed_primary_uuid

private

The primary to elect.

◆ current_action_phase

enum_primary_election_phase Primary_election_action::current_action_phase

private

The current phase.

◆ error_on_primary_election

bool Primary_election_action::error_on_primary_election

private

Was there an error in the election.

◆ execution_message_area

Group_action_diagnostics Primary_election_action::execution_message_area

private

Place to store result messages.

◆ invoking_member_gcs_id

std::string Primary_election_action::invoking_member_gcs_id

private

The id of the invoking primary.

◆ invoking_thread_id

my_thread_id Primary_election_action::invoking_thread_id

private

The thread that invoked this action - if applicable, 0 otherwise.

◆ is_primary

bool Primary_election_action::is_primary

private

If this member is old primary.

◆ is_primary_election_invoked

bool Primary_election_action::is_primary_election_invoked

private

Is the primary election invoked.

◆ is_transaction_queue_applied

bool Primary_election_action::is_transaction_queue_applied

private

Is the transaction back log consumed.

◆ m_execution_status

enum_primary_election_status Primary_election_action::m_execution_status {PRIMARY_ELECTION_INIT}

private

primary election status

◆ m_transaction_wait_timeout

int32 Primary_election_action::m_transaction_wait_timeout = {-1}

private

The number of seconds to wait before setting the THD::KILL_CONNECTION flag for the transactions that did not reach commit stage.

Client connection is dropped.

◆ notification_cond

mysql_cond_t Primary_election_action::notification_cond

private

The condition for notifications.

◆ notification_lock

mysql_mutex_t Primary_election_action::notification_lock

private

The lock for notifications.

◆ old_primary_uuid

std::string Primary_election_action::old_primary_uuid

private

The uuid of the original master at action invocation.

◆ phase_lock

mysql_mutex_t Primary_election_action::phase_lock

private

Lock for the phase change.

◆ single_election_action_aborted

bool Primary_election_action::single_election_action_aborted

private

Is this action aborted.

◆ transaction_monitor_thread

Transaction_monitor_thread* Primary_election_action::transaction_monitor_thread {nullptr}

private

Used to monitor transactions, this stops the new transactions and sets the THD::KILL_CONNECTION flag for the transactions that did not reach commit stage post timeout expire.

Client connection is dropped.

◆ validation_handler

Primary_election_validation_handler Primary_election_action::validation_handler

private

The handler for primary election validations.

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

plugin/group_replication/include/group_actions/primary_election_action.h
plugin/group_replication/src/group_actions/primary_election_action.cc

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ enum_action_execution_mode

◆ enum_primary_election_phase

◆ enum_primary_election_status

Constructor & Destructor Documentation

◆ Primary_election_action() [1/2]

◆ Primary_election_action() [2/2]

◆ ~Primary_election_action()

Member Function Documentation

◆ after_primary_election()

◆ after_view_change()

◆ before_message_handling()

◆ change_action_phase()

◆ execute_action()

◆ get_action_message()

◆ get_action_stage_termination_key()

◆ get_execution_info()

◆ log_result_execution()

◆ persist_variable_values()

◆ process_action_message()

◆ stop_action_execution()

◆ stop_transaction_monitor_thread()

Member Data Documentation

◆ action_execution_mode

◆ action_killed

◆ appointed_primary_gcs_id

◆ appointed_primary_uuid

◆ current_action_phase

◆ error_on_primary_election

◆ execution_message_area

◆ invoking_member_gcs_id

◆ invoking_thread_id

◆ is_primary

◆ is_primary_election_invoked

◆ is_transaction_queue_applied

◆ m_execution_status

◆ m_transaction_wait_timeout

◆ notification_cond

◆ notification_lock

◆ old_primary_uuid

◆ phase_lock

◆ single_election_action_aborted

◆ transaction_monitor_thread

◆ validation_handler