The coordinator class where group actions are submitted. More...

#include <group_action_coordinator.h>

Inheritance diagram for Group_action_coordinator:

Public Types
enum	enum_end_action_message_return_flags { END_ACTION_MESSAGE_UNKNOWN_FLAG = 0 , END_ACTION_MESSAGE_WARNING_FLAG = 1 , END_ACTION_MESSAGE_FLAG_END = 2 }
	Enum for the flags used in the return field of the end message. More...

Public Member Functions
	Group_action_coordinator (ulong components_stop_timeout)
	The group coordinator constructor. More...

	~Group_action_coordinator () override
	The group coordinator destructor More...

void	register_coordinator_observers ()
	Register the coordinator observers. More...

void	unregister_coordinator_observers ()
	Unregister the coordinator observers. More...

int	coordinate_action_execution (Group_action action, Group_action_diagnostics execution_info, Group_action_message::enum_action_initiator_and_action initiator)
	Submit an action for execution in the coordinator. More...

int	stop_coordinator_process (bool coordinator_stop, bool wait=true)
	Asks the coordinator to stop any ongoing action. More...

void	reset_coordinator_process ()
	Resets flags as the coordinator can live through multiple stops and starts. More...

bool	handle_action_message (Group_action_message *message, const std::string &message_origin)
	Handle incoming action message (start or stop) More...

bool	is_group_action_running (std::pair< std::string, std::string > &initiator)
	Returns if there is a group action running. More...

int	execute_group_action_handler ()
	The main thread process for the action execution process. More...

void	set_stop_wait_timeout (ulong timeout)
	Sets the component stop timeout. More...

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

Public Attributes
bool	failure_debug_flag
	Flag for cases where we don't have debug execution tools Can be an enum if other cases emerge. More...

Private Member Functions
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	handle_action_start_message (Group_action_message *message, const std::string &message_origin)
	Handle incoming start action message. More...

bool	handle_action_stop_message (Group_action_message *message, const std::string &message_origin)
	Handle incoming end action message. More...

bool	member_in_recovery (Group_member_info_list *all_members_info)
	This method checks if there is a member in recovery in the group. More...

bool	member_from_invalid_version (Group_member_info_list *all_members_info)
	This method checks if there is a member from a version that does not allow actions. More...

void	awake_coordinator_on_error (Group_action_information execution_info, const char error_message, bool is_local_executor, bool is_action_running=false)
	Set an error message and awake the coordinator. More...

void	awake_coordinator_on_error (Group_action_information *execution_info, bool is_local_executor, bool is_action_running=false)
	Awake the coordinator and report the error. More...

int	signal_action_terminated ()
	Declare this action as terminated to other members. More...

void	terminate_action ()
	Handle the termination of current action. More...

void	signal_and_wait_action_termination (bool wait)
	Declares the action as not running, wait or not for its finish. More...

bool	thread_killed ()
	This method returns if the current thread was killed. More...

int	launch_group_action_handler_thread ()
	launch_group_action_handler_thread More...

Private Attributes
std::list< std::string >	known_members_addresses
	The list of members known for the current action. More...

int	number_of_known_members
	The number of received stop messages or dead members. More...

int	number_of_terminated_members
	The number of received stop messages or dead members. More...

mysql_mutex_t	coordinator_process_lock
	The lock too coordinate start and stop requests. More...

mysql_cond_t	coordinator_process_condition
	The condition to wake up on error or termination. More...

bool	is_sender
	Is this member the sender and controller of this action. More...

bool	action_proposed
	The flag to avoid concurrent action start requests. More...

std::atomic< bool >	action_running
	The flag to avoid concurrent action running. More...

Group_action_information *	proposed_action
	The currently proposed action owner. More...

Group_action_information *	current_executing_action
	The currently proposed action owner. More...

bool	local_action_terminating
	Is the local submitted action terminating. More...

bool	local_action_killed
	Was the local action killed. More...

bool	action_execution_error
	Is there an error on the message after receiving the action. More...

bool	coordinator_terminating
	The flag to avoid action starts post stop. More...

bool	action_cancelled_on_termination
	If we propose an action but the coordinator ends before it starts. More...

bool	member_leaving_group
	Is this member leaving. More...

bool	remote_warnings_reported
	There were remote warnings reported. More...

Plugin_stage_monitor_handler	monitoring_stage_handler
	The handler where actions can report progress through stages. More...

thread_state	action_handler_thd_state
	The action handler thread status. More...

bool	is_group_action_being_executed
	If the group action execution method is being executed. More...

ulong	stop_wait_timeout

my_thread_handle	action_execution_pthd
	The thread handle for the group action process. More...

mysql_mutex_t	group_thread_run_lock
	The group action process thread lock. More...

mysql_cond_t	group_thread_run_cond
	The group action process thread condition. More...

mysql_mutex_t	group_thread_end_lock
	The group action process thread end lock. More...

mysql_cond_t	group_thread_end_cond
	The group action process thread end condition. More...

Detailed Description

The coordinator class where group actions are submitted.

Member Enumeration Documentation

◆ enum_end_action_message_return_flags

enum Group_action_coordinator::enum_end_action_message_return_flags

Enum for the flags used in the return field of the end message.

Enumerator
END_ACTION_MESSAGE_UNKNOWN_FLAG
END_ACTION_MESSAGE_WARNING_FLAG
END_ACTION_MESSAGE_FLAG_END

Constructor & Destructor Documentation

◆ Group_action_coordinator()

Group_action_coordinator::Group_action_coordinator ( ulong components_stop_timeout )

The group coordinator constructor.

The 'action' / 'action information' object life cycle:

Parameters

[in] components_stop_timeout the timeout when waiting on shutdown

The action comes from the coordinate_action_execution. It is set as current_proposed_action and only when the start message is received we decide if it is accepted or not.

If accepted, the current_executing_action is set to the proposed action.

Some notes on current_executing_action. 1) It is set on the handle_action_start_message. There is no lock, we just ensure it is set before the action_running is set to true. 2) It is deleted under the coordinator_process_lock on terminate_action or awake_coordinator_on_error If it was proposed locally the code proposing the action will delete the object on coordinate_action_execution. 3) All accesses are under the execution of the said action on the thread, or on the coordination or stop methods, were we use the coordinator_process_lock

Action_running the flag:

Since it is accessed in multiple places and contexts we use an atomic value

The base of the flag is that in GCS invoked methods it is set to true on handle_action_start_message (Gcs logical moment) set to false on terminate_action (Gcs logical moment)

On critical action errors it can be set to false on awake_coordinator_on_error. This usually means the member will leave the group or the coordinator is stopping, meaning new actions won't be accepted or processed since the member left.

There is a wait based on this variable in the execute_group_action_handler but for that reason we have the group_thread_end_lock.

current_executing_action checks the variable in a optimistic to ensure a fail fast code path. It is also used to check if we should stop an action when the query is killed. For this we first set local_action_killed to ensure that start will fail when receives the action, and then we try to stop the action if it is already running.

The stop_coordinator_process works on the same approach, it checks if the an action is running the but coordinator_terminating flag is set first, so if we miss the action start, it will fail due to the flag.

◆ ~Group_action_coordinator()

Group_action_coordinator::~Group_action_coordinator ( )

override

The group coordinator destructor

Member Function Documentation

◆ after_primary_election()

int Group_action_coordinator::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 Group_action_coordinator::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

Implements Group_event_observer.

◆ awake_coordinator_on_error() [1/2]

void Group_action_coordinator::awake_coordinator_on_error	(	Group_action_information *	execution_info,
		bool	is_local_executor,
		bool	is_action_running = `false`
	)

private

Awake the coordinator and report the error.

Parameters

execution_info	The information for the executing action
is_local_executor	are we aborting something proposed on this member
is_action_running	if the action was already running

◆ awake_coordinator_on_error() [2/2]

void Group_action_coordinator::awake_coordinator_on_error	(	Group_action_information *	execution_info,
		const char *	error_message,
		bool	is_local_executor,
		bool	is_action_running = `false`
	)

private

Set an error message and awake the coordinator.

Parameters

execution_info	The information for the executing action
error_message	the message to send to the user if local
is_local_executor	are we aborting something proposed on this member
is_action_running	if the action was already running

◆ before_message_handling()

int Group_action_coordinator::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.

◆ coordinate_action_execution()

int Group_action_coordinator::coordinate_action_execution	(	Group_action *	action,
		Group_action_diagnostics *	execution_info,
		Group_action_message::enum_action_initiator_and_action	initiator
	)

Submit an action for execution in the coordinator.

Parameters

action	The action instance to execute in the group
execution_info	The result information for this action execution
initiator	Details of initiator and action

Returns: !=0 if something wrong happened in the action

◆ execute_group_action_handler()

int Group_action_coordinator::execute_group_action_handler ( )

The main thread process for the action execution process.

Did the action terminate locally but not remotely? Just add a warning and return.

◆ handle_action_message()

bool Group_action_coordinator::handle_action_message	(	Group_action_message *	message,
		const std::string &	message_origin
	)

Handle incoming action message (start or stop)

Parameters

message	The action message pointer
message_origin	the message origin

Returns: true if something wrong happen, false otherwise

◆ handle_action_start_message()

bool Group_action_coordinator::handle_action_start_message	(	Group_action_message *	message,
		const std::string &	message_origin
	)

private

Handle incoming start action message.

Parameters

message	The action message pointer
message_origin	the message origin

Returns: true if something wrong happen, false otherwise

Double check for termination /killing request in case the code sees action_running as being false

◆ handle_action_stop_message()

bool Group_action_coordinator::handle_action_stop_message	(	Group_action_message *	message,
		const std::string &	message_origin
	)

private

Handle incoming end action message.

Parameters

message	The action message pointer
message_origin	the message origin

Returns: true if something wrong happen, false otherwise

◆ is_group_action_running()

bool Group_action_coordinator::is_group_action_running ( std::pair< std::string, std::string > & initiator )

Returns if there is a group action running.

Parameters

[out] initiator action name and description if running

Returns: true if an action is being executed

◆ launch_group_action_handler_thread()

int Group_action_coordinator::launch_group_action_handler_thread ( )

private

launch_group_action_handler_thread

◆ member_from_invalid_version()

bool Group_action_coordinator::member_from_invalid_version ( Group_member_info_list * all_members_info )

private

This method checks if there is a member from a version that does not allow actions.

Parameters

all_members_info the list of info objects for all members

Returns: true if yes, false if all members are valid

◆ member_in_recovery()

bool Group_action_coordinator::member_in_recovery ( Group_member_info_list * all_members_info )

private

This method checks if there is a member in recovery in the group.

Parameters

all_members_info the list of info objects for all members

Returns: true if yes, false if no member is in recovery

◆ register_coordinator_observers()

void Group_action_coordinator::register_coordinator_observers ( )

Register the coordinator observers.

Note: Calling this method in constructors/destructors can lead to errors as virtual methods are called upon an "incomplete" object.

◆ reset_coordinator_process()

void Group_action_coordinator::reset_coordinator_process ( )

Resets flags as the coordinator can live through multiple stops and starts.

◆ set_stop_wait_timeout()

void Group_action_coordinator::set_stop_wait_timeout ( ulong timeout )

Sets the component stop timeout.

Parameters

[in] timeout the timeout

◆ signal_action_terminated()

int Group_action_coordinator::signal_action_terminated ( )

private

Declare this action as terminated to other members.

◆ signal_and_wait_action_termination()

void Group_action_coordinator::signal_and_wait_action_termination ( bool wait )

private

Declares the action as not running, wait or not for its finish.

Parameters

wait	wait for the execution thread to finish or not

◆ stop_coordinator_process()

int Group_action_coordinator::stop_coordinator_process	(	bool	coordinator_stop,
		bool	wait = `true`
	)

Asks the coordinator to stop any ongoing action.

Parameters

coordinator_stop	is the coordinator terminating
wait	shall it wait for the process to terminate

If we sent a start message but then left the group, the action might be waiting

Either the action will end and will see the coordinator stop flag, or we wake it up in here

◆ terminate_action()

void Group_action_coordinator::terminate_action ( )

private

Handle the termination of current action.

◆ thread_killed()

bool Group_action_coordinator::thread_killed ( )

private

This method returns if the current thread was killed.

Returns: true if yes, false otherwise

◆ unregister_coordinator_observers()

void Group_action_coordinator::unregister_coordinator_observers ( )

Unregister the coordinator observers.

Note: Calling this method in constructors/destructors can lead to errors as virtual methods are called upon an "incomplete" object.

Member Data Documentation

◆ action_cancelled_on_termination

bool Group_action_coordinator::action_cancelled_on_termination

private

If we propose an action but the coordinator ends before it starts.

◆ action_execution_error

bool Group_action_coordinator::action_execution_error

private

Is there an error on the message after receiving the action.

◆ action_execution_pthd

my_thread_handle Group_action_coordinator::action_execution_pthd

private

The thread handle for the group action process.

◆ action_handler_thd_state

thread_state Group_action_coordinator::action_handler_thd_state

private

The action handler thread status.

◆ action_proposed

bool Group_action_coordinator::action_proposed

private

The flag to avoid concurrent action start requests.

◆ action_running

std::atomic<bool> Group_action_coordinator::action_running

private

The flag to avoid concurrent action running.

◆ coordinator_process_condition

mysql_cond_t Group_action_coordinator::coordinator_process_condition

private

The condition to wake up on error or termination.

◆ coordinator_process_lock

mysql_mutex_t Group_action_coordinator::coordinator_process_lock

private

The lock too coordinate start and stop requests.

◆ coordinator_terminating

bool Group_action_coordinator::coordinator_terminating

private

The flag to avoid action starts post stop.

◆ current_executing_action

Group_action_information* Group_action_coordinator::current_executing_action

private

The currently proposed action owner.

◆ failure_debug_flag

bool Group_action_coordinator::failure_debug_flag

Flag for cases where we don't have debug execution tools Can be an enum if other cases emerge.

◆ group_thread_end_cond

mysql_cond_t Group_action_coordinator::group_thread_end_cond

private

The group action process thread end condition.

◆ group_thread_end_lock

mysql_mutex_t Group_action_coordinator::group_thread_end_lock

private

The group action process thread end lock.

◆ group_thread_run_cond

mysql_cond_t Group_action_coordinator::group_thread_run_cond

private

The group action process thread condition.

◆ group_thread_run_lock

mysql_mutex_t Group_action_coordinator::group_thread_run_lock

private

The group action process thread lock.

◆ is_group_action_being_executed

bool Group_action_coordinator::is_group_action_being_executed

private

If the group action execution method is being executed.

◆ is_sender

bool Group_action_coordinator::is_sender

private

Is this member the sender and controller of this action.

◆ known_members_addresses

std::list<std::string> Group_action_coordinator::known_members_addresses

private

The list of members known for the current action.

◆ local_action_killed

bool Group_action_coordinator::local_action_killed

private

Was the local action killed.

◆ local_action_terminating

bool Group_action_coordinator::local_action_terminating

private

Is the local submitted action terminating.

◆ member_leaving_group

bool Group_action_coordinator::member_leaving_group

private

Is this member leaving.

◆ monitoring_stage_handler

Plugin_stage_monitor_handler Group_action_coordinator::monitoring_stage_handler

private

The handler where actions can report progress through stages.

◆ number_of_known_members

int Group_action_coordinator::number_of_known_members

private

The number of received stop messages or dead members.

◆ number_of_terminated_members

int Group_action_coordinator::number_of_terminated_members

private

The number of received stop messages or dead members.

◆ proposed_action

Group_action_information* Group_action_coordinator::proposed_action

private

The currently proposed action owner.

◆ remote_warnings_reported

bool Group_action_coordinator::remote_warnings_reported

private

There were remote warnings reported.

◆ stop_wait_timeout

ulong Group_action_coordinator::stop_wait_timeout

private

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

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

Public Types

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ enum_end_action_message_return_flags

Constructor & Destructor Documentation

◆ Group_action_coordinator()

◆ ~Group_action_coordinator()

Member Function Documentation

◆ after_primary_election()

◆ after_view_change()

◆ awake_coordinator_on_error() [1/2]

◆ awake_coordinator_on_error() [2/2]

◆ before_message_handling()

◆ coordinate_action_execution()

◆ execute_group_action_handler()

◆ handle_action_message()

◆ handle_action_start_message()

◆ handle_action_stop_message()

◆ is_group_action_running()

◆ launch_group_action_handler_thread()

◆ member_from_invalid_version()

◆ member_in_recovery()

◆ register_coordinator_observers()

◆ reset_coordinator_process()

◆ set_stop_wait_timeout()

◆ signal_action_terminated()

◆ signal_and_wait_action_termination()

◆ stop_coordinator_process()

◆ terminate_action()

◆ thread_killed()

◆ unregister_coordinator_observers()

Member Data Documentation

◆ action_cancelled_on_termination

◆ action_execution_error

◆ action_execution_pthd

◆ action_handler_thd_state

◆ action_proposed

◆ action_running

◆ coordinator_process_condition

◆ coordinator_process_lock

◆ coordinator_terminating

◆ current_executing_action

◆ failure_debug_flag

◆ group_thread_end_cond

◆ group_thread_end_lock

◆ group_thread_run_cond

◆ group_thread_run_lock

◆ is_group_action_being_executed

◆ is_sender

◆ known_members_addresses

◆ local_action_killed

◆ local_action_terminating

◆ member_leaving_group

◆ monitoring_stage_handler

◆ number_of_known_members

◆ number_of_terminated_members

◆ proposed_action

◆ remote_warnings_reported

◆ stop_wait_timeout