Applier_handler Class Reference

#include <applier_handler.h>

Inheritance diagram for Applier_handler:

Public Member Functions
	Applier_handler ()
int	handle_event (Pipeline_event *ev, Continuation *cont) override
	Handling of an event as defined in the handler implementation. More...
int	handle_action (Pipeline_action *action) override
	Handling of an action as defined in the handler implementation. More...
int	initialize () override
	Initialization as defined in the handler implementation. More...
int	terminate () override
	Terminate the execution as defined in the handler implementation. More...
bool	is_unique () override
	This method identifies the handler as being unique. More...
int	get_role () override
	This method returns the handler role. More...
int	handle_binary_log_event (Pipeline_event *pevent, Continuation *cont)
	This method handles binary log events by storing them so they can be used on next handler. More...
int	handle_applier_event (Pipeline_event *pevent, Continuation *cont)
	This method handles applier context events by storing them so they can be used on next handler. More...
int	initialize_repositories (bool reset_logs, ulong plugin_shutdown_timeout)
	Initializes the SQL thread when receiving a configuration package. More...
int	start_applier_thread ()
	Starts the SQL thread when receiving a action package. More...
int	stop_applier_thread ()
	Stops the SQL thread when receiving a action package. More...
bool	is_applier_thread_waiting ()
	Checks if the applier, and its workers when parallel applier is enabled, has already consumed all relay log, that is, applier is waiting for transactions to be queued. More...
int	wait_for_gtid_execution (double timeout)
	Checks if all the queued transactions were executed. More...
int	wait_for_gtid_execution (std::string &retrieved_set, double timeout, bool update_THD_status=true)
	Checks if all the given transactions were executed. More...
int	is_partial_transaction_on_relay_log ()
	Checks if the channel's relay log contains partial transaction. More...
Public Member Functions inherited from Event_handler
	Event_handler ()
virtual	~Event_handler ()=default
void	plug_next_handler (Event_handler *next_handler)
	Plug an handler to be the next in line for execution. More...
void	append (Event_handler *last_handler)
	Append an handler to be the last in line for execution. More...
int	terminate_pipeline ()
	Shutdown and delete all handlers in the pipeline. More...

Private Attributes
Replication_thread_api	channel_interface

Additional Inherited Members
Static Public Member Functions inherited from Event_handler
static void	append_handler (Event_handler **pipeline, Event_handler *event_handler)
	Append an handler to a given pipeline. More...
static void	get_handler_by_role (Event_handler *pipeline, int role, Event_handler **event_handler)
	Returns an handler that plays the given role. More...
Protected Member Functions inherited from Event_handler
int	next (Pipeline_event *event, Continuation *continuation)
	Pass the event to the next handler in line. More...
int	next (Pipeline_action *action)
	Pass the action to the next handler in line. More...

Constructor & Destructor Documentation

Applier_handler()

Applier_handler::Applier_handler ( )

default

Member Function Documentation

get_role()

int Applier_handler::get_role ( )

overridevirtual

This method returns the handler role.

Handlers can have different roles according to the tasks they represent. Is based on this role that certain components can extract and interact with pipeline handlers. This means that if a role is given to a singleton handler, no one else can have that role.

Returns

the handler role

Implements Event_handler.

handle_action()

int Applier_handler::handle_action ( Pipeline_action *  action )

overridevirtual

Handling of an action as defined in the handler implementation.

As the handler can be included in a pipeline, somewhere in the method, the handler.next(action) method shall be invoked to allow the passing of the action to the next handler.

Note

Actions should not be treated asynchronously and as so, Continuations are not used here. Errors are returned directly or passed by in the action if it includes support for such

Parameters

[in]

action

the pipeline event to be handled

Implements Event_handler.

handle_applier_event()

int Applier_handler::handle_applier_event	(	Pipeline_event *	pevent,
		Continuation *	cont
	)

This method handles applier context events by storing them so they can be used on next handler.

Parameters

[in]	pevent	the event to be injected
[in]	cont	the object used to wait

Returns

the operation status

Return values

0	OK
!=0	Error

handle_binary_log_event()

int Applier_handler::handle_binary_log_event	(	Pipeline_event *	pevent,
		Continuation *	cont
	)

This method handles binary log events by storing them so they can be used on next handler.

Parameters

[in]	pevent	the event to be injected
[in]	cont	the object used to wait

Returns

the operation status

Return values

0	OK
!=0	Error

handle_event()

int Applier_handler::handle_event ( Pipeline_event *  event, Continuation *  continuation  )

overridevirtual

Handling of an event as defined in the handler implementation.

As the handler can be included in a pipeline, somewhere in the method, the handler.next(event,continuation) method shall be invoked to allow the passing of the event to the next handler.

Also, if an error occurs, the continuation object shall be used to propagate such error. This class can also be used to know/report when the transaction to whom the event belongs was discarded.

Parameters

[in]	event	the pipeline event to be handled
[in,out]	continuation	termination notification object.

Implements Event_handler.

initialize()

int Applier_handler::initialize ( )

overridevirtual

Initialization as defined in the handler implementation.

Note

It's up to the developer to decide its own initialization strategy, but the suggested approach is to initialize basic structures here and then depend on Action packets to configure and start existing handler routines.

Implements Event_handler.

initialize_repositories()

int Applier_handler::initialize_repositories	(	bool	reset_logs,
		ulong	plugin_shutdown_timeout
	)

Initializes the SQL thread when receiving a configuration package.

Parameters

reset_logs	if a reset was executed in the server
plugin_shutdown_timeout	the plugin's timeout for component shutdown

Returns

the operation status

Return values

0	OK
!=0	Error

is_applier_thread_waiting()

bool Applier_handler::is_applier_thread_waiting

(

)

Checks if the applier, and its workers when parallel applier is enabled, has already consumed all relay log, that is, applier is waiting for transactions to be queued.

Returns

the applier status

Return values

true	the applier is waiting
false	otherwise

is_partial_transaction_on_relay_log()

int Applier_handler::is_partial_transaction_on_relay_log

(

)

Checks if the channel's relay log contains partial transaction.

Return values

true	If relaylog contains partial transaction.
false	If relaylog does not contain partial transaction.

is_unique()

bool Applier_handler::is_unique ( )

overridevirtual

This method identifies the handler as being unique.

An handler that is defined as unique is an handler that cannot be used more than once in a pipeline. Such tasks as certification and event application can only be done once. Unique handlers are also the only that, by being one of a kind, can be extracted during the pipeline life allowing dynamic changes to them.

Returns

if the handler is the a unique handler

Return values

true	is a unique handler
false	is a repeatable handler

Implements Event_handler.

start_applier_thread()

int Applier_handler::start_applier_thread

(

)

Starts the SQL thread when receiving a action package.

Returns

the operation status

Return values

0	OK
!=0	Error

stop_applier_thread()

int Applier_handler::stop_applier_thread

(

)

Stops the SQL thread when receiving a action package.

Returns

the operation status

Return values

0	OK
!=0	Error

terminate()

int Applier_handler::terminate ( )

overridevirtual

Terminate the execution as defined in the handler implementation.

Implements Event_handler.

wait_for_gtid_execution() [1/2]

int Applier_handler::wait_for_gtid_execution

(

double

timeout

)

Checks if all the queued transactions were executed.

Parameters

timeout

the time (seconds) after which the method returns if the above condition was not satisfied

Returns

the operation status

Return values

0	All transactions were executed
-1	A timeout occurred
-2	An error occurred

wait_for_gtid_execution() [2/2]

int Applier_handler::wait_for_gtid_execution	(	std::string &	retrieved_set,
		double	timeout,
		bool	update_THD_status = true
	)

Checks if all the given transactions were executed.

Parameters

retrieved_set	the set in string format of transaction to wait for
timeout	the time (seconds) after which the method returns if the above condition was not satisfied
update_THD_status	Shall the method update the THD stage

Returns

the operation status

Return values

0	All transactions were executed
-1	A timeout occurred
-2	An error occurred

Member Data Documentation

channel_interface

Replication_thread_api Applier_handler::channel_interface

private

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

• plugin/group_replication/include/handlers/applier_handler.h
• plugin/group_replication/src/handlers/applier_handler.cc