Remote_clone_handler Class Reference

Class that hold the logic to decide if we should or not execute a clone operation and the logic to launch it. More...

#include <remote_clone_handler.h>

Inheritance diagram for Remote_clone_handler:

Public Types
enum	enum_clone_check_result {   DO_CLONE = 0 , DO_RECOVERY = 1 , CHECK_ERROR = 2 , NO_RECOVERY_POSSIBLE = 3 ,   CLONE_CHECKS_END = 4 }
	The possible results when checking what is the recovery strategy. More...

Public Member Functions
	Remote_clone_handler (ulonglong threshold, ulong components_stop_timeout)
	Constructor for the remote cloning handler. More...
	~Remote_clone_handler () override
	The destructor. More...
void	set_clone_threshold (ulonglong threshold)
	Set the class threshold for clone activation. More...
int	extract_donor_info (std::tuple< uint, uint, uint, bool > *donor_info)
enum_clone_check_result	check_clone_preconditions ()
	Check if clone or distributed recovery shall be used for provisioning. More...
int	clone_server (const std::string &group_name, const std::string &view_id)
	Launch the clone process with some preliminary checks. More...
void	terminate_clone_process (bool rejoin)
	Terminate the clone process. More...
void	lock_gr_clone_read_mode_lock ()
	Lock when trying to set the read mode and a clone might be running. More...
void	unlock_gr_clone_read_mode_lock ()
	Unlock when trying to set the read mode and a clone might be running. More...
Public Member Functions inherited from Group_event_observer
virtual	~Group_event_observer ()=0

Private Types
enum	enum_clone_presence_query_result { CLONE_PLUGIN_NOT_PRESENT = 0 , CLONE_PLUGIN_PRESENT = 1 , CLONE_CHECK_QUERY_ERROR = 2 }
	What is the result when we check if the clone plugin is present. More...
enum	enum_clone_query_status { CLONE_QUERY_NOT_EXECUTING = 0 , CLONE_QUERY_EXECUTING = 1 , CLONE_QUERY_EXECUTED = 2 }
	What are the states of the clone execution query. 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...
void	clone_thread_handle ()
	The clone thread process. More...
enum_clone_presence_query_result	check_clone_plugin_presence ()
	Check if clone plugin is present. More...
void	get_clone_donors (std::list< Group_member_info * > &suitable_donors)
	Get all the valid members for cloning. More...
int	set_clone_ssl_options (Sql_service_command_interface *sql_command_interface)
	Configure the SSL options for the clone plugin. More...
int	fallback_to_recovery_or_leave (bool critical_error=false)
	In error fall back to recovery or error out. More...
int	update_donor_list (Sql_service_command_interface *sql_command_interface, std::string &hostname, std::string &port)
	Executes the query to change the allowed donor list for clone. More...
int	evaluate_server_connection (Sql_service_command_interface *sql_command_interface)
	Checks if the server connection was not killed. More...
int	run_clone_query (Sql_service_command_interface *sql_command_interface, std::string &hostname, std::string &port, std::string &username, std::string &password, bool use_ssl)
	Executes the query to remotely clone a server. More...
int	kill_clone_query ()
	Kill the current query executing a clone. More...
bool	evaluate_error_code (int error_code)
	Given a error code it evaluates if the error is critical or not. More...
void	gr_clone_debug_point ()
	Function for debug points. More...

Static Private Member Functions
static void *	launch_thread (void *arg)
	The thread callback passed onto mysql_thread_create. More...

Private Attributes
std::string	m_group_name
	The group to which the recovering member belongs. More...
std::string	m_view_id
	The view id when the clone started. More...
THD *	m_clone_thd
	the THD handle. More...
thread_state	m_clone_process_thd_state
	the state of the thread. More...
my_thread_handle	m_thd_handle
	the thread handle. More...
mysql_mutex_t	m_run_lock
	the mutex for controlling access to the thread itself. More...
mysql_cond_t	m_run_cond
	the cond_var used to signal the thread. More...
mysql_mutex_t	m_clone_query_lock
	the mutex for the clone process query. More...
mysql_mutex_t	m_clone_read_mode_lock
	the mutex for the clone external running status/read mode More...
bool	m_being_terminated
	Is the process being terminated. More...
enum_clone_query_status	m_clone_query_status
	What is the status on the read only mode enabling query. More...
unsigned long	m_clone_query_session_id
	The session id for the clone query. More...
ulonglong	m_clone_activation_threshold
	The threshold after which the clone process is invoked. More...
mysql_mutex_t	m_donor_list_lock
	the mutex for donor list accesses. More...
std::list< Group_member_info * >	m_suitable_donors
	The list of available donors. More...
Gcs_member_identifier *	m_current_donor_address
	The current donor address. More...
ulong	m_stop_wait_timeout
	Timeout on shutdown. More...

Detailed Description

Class that hold the logic to decide if we should or not execute a clone operation and the logic to launch it.

Member Enumeration Documentation

enum_clone_check_result

enum Remote_clone_handler::enum_clone_check_result

The possible results when checking what is the recovery strategy.

Enumerator
DO_CLONE
DO_RECOVERY
CHECK_ERROR
NO_RECOVERY_POSSIBLE
CLONE_CHECKS_END

enum_clone_presence_query_result

enum Remote_clone_handler::enum_clone_presence_query_result

private

What is the result when we check if the clone plugin is present.

Enumerator
CLONE_PLUGIN_NOT_PRESENT
CLONE_PLUGIN_PRESENT
CLONE_CHECK_QUERY_ERROR

enum_clone_query_status

enum Remote_clone_handler::enum_clone_query_status

private

What are the states of the clone execution query.

Enumerator
CLONE_QUERY_NOT_EXECUTING
CLONE_QUERY_EXECUTING
CLONE_QUERY_EXECUTED

Constructor & Destructor Documentation

Remote_clone_handler()

Remote_clone_handler::Remote_clone_handler	(	ulonglong	threshold,
		ulong	components_stop_timeout
	)

Constructor for the remote cloning handler.

Parameters

threshold	The threshold for clone activation
components_stop_timeout	The stop timeout in error cases

~Remote_clone_handler()

Remote_clone_handler::~Remote_clone_handler ( )

override

The destructor.

Member Function Documentation

after_primary_election()

int Remote_clone_handler::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 Remote_clone_handler::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.

before_message_handling()

int Remote_clone_handler::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.

check_clone_plugin_presence()

Remote_clone_handler::enum_clone_presence_query_result Remote_clone_handler::check_clone_plugin_presence ( )

private

Check if clone plugin is present.

Returns

is the clone present or error

Return values

CLONE_PLUGIN_NOT_PRESENT	The plugin is not present or active
CLONE_PLUGIN_PRESENT	The plugin is present and active
CLONE_CHECK_QUERY_ERROR	There was an error when checking

check_clone_preconditions()

Remote_clone_handler::enum_clone_check_result Remote_clone_handler::check_clone_preconditions

(

)

Check if clone or distributed recovery shall be used for provisioning.

Returns

What is the clone strategy to follow or shall we error out

Return values

DO_CLONE	Do a remote clone
DO_RECOVERY	Don't clone, use distributed recovery
CHECK_ERROR	Error when choosing the strategy
NO_RECOVERY_POSSIBLE	No available members for clone or recovery

clone_server()

int Remote_clone_handler::clone_server	(	const std::string &	group_name,
		const std::string &	view_id
	)

Launch the clone process with some preliminary checks.

Parameters

group_name	The group name
view_id	The view id when clone started

Note

: the given parameters are used when falling back to distributed recovery in case of a clone issue.

Returns

whether or not we managed to launch the clone thread.

Return values

0	the thread launched successfully
!=	0 for some reason we did not launch the thread

clone_thread_handle()

void Remote_clone_handler::clone_thread_handle ( )

private

The clone thread process.

evaluate_error_code()

bool Remote_clone_handler::evaluate_error_code ( int  error_code )

private

Given a error code it evaluates if the error is critical or not.

Basically it tells us if there is still data in the server.

Parameters

[in]

error_code

the clone returned error

Return values

true	error is critical
false	error is not critical

evaluate_server_connection()

int Remote_clone_handler::evaluate_server_connection ( Sql_service_command_interface *  sql_command_interface )

private

Checks if the server connection was not killed.

If so, establish a new one.

Parameters

[in]

sql_command_interface

the server connection

Returns

did we manage to reconnect

Return values

0	yes
!=	0 some error occurred

extract_donor_info()

int Remote_clone_handler::extract_donor_info

(

std::tuple< uint, uint, uint, bool > *

donor_info

)

fallback_to_recovery_or_leave()

int Remote_clone_handler::fallback_to_recovery_or_leave ( bool  critical_error = false )

private

In error fall back to recovery or error out.

Parameters

[in]

critical_error

the error prevent distributed recovery

Before falling back to recovery check if there are valid donors Since cloning can be time consuming valid members may have left or joined in the meanwhile.

get_clone_donors()

void Remote_clone_handler::get_clone_donors ( std::list< Group_member_info * > &  suitable_donors )

private

Get all the valid members for cloning.

Parameters

[out]

suitable_donors

the list of possible donors

gr_clone_debug_point()

void Remote_clone_handler::gr_clone_debug_point ( )

private

Function for debug points.

Note

this function can have a parameter for different debug points

kill_clone_query()

int Remote_clone_handler::kill_clone_query ( )

private

Kill the current query executing a clone.

Returns

whether or not we managed to kill the clone query

Return values

0	the kill query was successful
!=	0 some error occurred

launch_thread()

void * Remote_clone_handler::launch_thread ( void *  arg )

staticprivate

The thread callback passed onto mysql_thread_create.

Parameters

[in]

arg

a pointer to a Remote_clone_handler instance.

Returns

Does not return.

lock_gr_clone_read_mode_lock()

void Remote_clone_handler::lock_gr_clone_read_mode_lock ( )

inline

Lock when trying to set the read mode and a clone might be running.

run_clone_query()

int Remote_clone_handler::run_clone_query ( Sql_service_command_interface *  sql_command_interface, std::string &  hostname, std::string &  port, std::string &  username, std::string &  password, bool  use_ssl  )

private

Executes the query to remotely clone a server.

Parameters

[in]	sql_command_interface	the connection to use
[in]	hostname	the hostname to use
[in]	port	the port to use
[in]	username	the username to use
[in]	password	the password to use
[in]	use_ssl	make clone use SSL

Returns

whether or not we managed to clone the server

Return values

0	the clone was successful
!=	0 some error occurred

set_clone_ssl_options()

int Remote_clone_handler::set_clone_ssl_options ( Sql_service_command_interface *  sql_command_interface )

private

Configure the SSL options for the clone plugin.

Parameters

[in]

sql_command_interface

the connection to use

set_clone_threshold()

void Remote_clone_handler::set_clone_threshold ( ulonglong  threshold )

inline

Set the class threshold for clone activation.

Parameters

threshold

The threshold for clone activation

terminate_clone_process()

void Remote_clone_handler::terminate_clone_process

(

bool

rejoin

)

Terminate the clone process.

Parameters

rejoin

Are we terminating or rejoining in the plugin

Note

: the flag tells the method if the clone query should be killed or not Usually on rejoins the clone query is not killed. When stopping GR, then the query is terminated. No guarantees are made about what the server state is after that

unlock_gr_clone_read_mode_lock()

void Remote_clone_handler::unlock_gr_clone_read_mode_lock ( )

inline

Unlock when trying to set the read mode and a clone might be running.

update_donor_list()

int Remote_clone_handler::update_donor_list ( Sql_service_command_interface *  sql_command_interface, std::string &  hostname, std::string &  port  )

private

Executes the query to change the allowed donor list for clone.

Parameters

[in]	sql_command_interface	the connection to use
[in]	hostname	the hostname to set
[in]	port	the port to set

Returns

whether or not we managed to set the value

Return values

0	the value was set
!=	0 some error occurred

Member Data Documentation

m_being_terminated

bool Remote_clone_handler::m_being_terminated

private

Is the process being terminated.

m_clone_activation_threshold

ulonglong Remote_clone_handler::m_clone_activation_threshold

private

The threshold after which the clone process is invoked.

m_clone_process_thd_state

thread_state Remote_clone_handler::m_clone_process_thd_state

private

the state of the thread.

m_clone_query_lock

mysql_mutex_t Remote_clone_handler::m_clone_query_lock

private

the mutex for the clone process query.

m_clone_query_session_id

unsigned long Remote_clone_handler::m_clone_query_session_id

private

The session id for the clone query.

m_clone_query_status

enum_clone_query_status Remote_clone_handler::m_clone_query_status

private

What is the status on the read only mode enabling query.

m_clone_read_mode_lock

mysql_mutex_t Remote_clone_handler::m_clone_read_mode_lock

private

the mutex for the clone external running status/read mode

m_clone_thd

THD* Remote_clone_handler::m_clone_thd

private

the THD handle.

m_current_donor_address

Gcs_member_identifier* Remote_clone_handler::m_current_donor_address

private

The current donor address.

m_donor_list_lock

mysql_mutex_t Remote_clone_handler::m_donor_list_lock

private

the mutex for donor list accesses.

m_group_name

std::string Remote_clone_handler::m_group_name

private

The group to which the recovering member belongs.

m_run_cond

mysql_cond_t Remote_clone_handler::m_run_cond

private

the cond_var used to signal the thread.

m_run_lock

mysql_mutex_t Remote_clone_handler::m_run_lock

private

the mutex for controlling access to the thread itself.

m_stop_wait_timeout

ulong Remote_clone_handler::m_stop_wait_timeout

private

Timeout on shutdown.

m_suitable_donors

std::list<Group_member_info *> Remote_clone_handler::m_suitable_donors

private

The list of available donors.

m_thd_handle

my_thread_handle Remote_clone_handler::m_thd_handle

private

the thread handle.

m_view_id

std::string Remote_clone_handler::m_view_id

private

The view id when the clone started.

---

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

• plugin/group_replication/include/plugin_handlers/remote_clone_handler.h
• plugin/group_replication/src/plugin_handlers/remote_clone_handler.cc