The major logic of dump thread is implemented in this class. More...

#include <rpl_binlog_sender.h>

Classes
class	Event_allocator
	Binlog_sender reads events one by one. More...

Public Member Functions
	Binlog_sender (THD thd, const char start_file, my_off_t start_pos, Gtid_set *exclude_gtids, uint32 flag)

	~Binlog_sender ()=default

void	run ()
	It checks the dump request and sends events to the client until it finish all events(for mysqlbinlog) or encounters an error. More...

void	set_prev_event_type (mysql::binlog::event::Log_event_type type)
	Sets the value of the previously processed event. More...

Private Types
typedef Basic_binlog_file_reader< Binlog_ifile, Binlog_event_data_istream, Binlog_event_object_istream, Event_allocator >	File_reader

Private Member Functions
bool	stop_waiting_for_update (my_off_t log_pos) const
	Checks whether thread should continue awaiting new events. More...

void	init ()

void	cleanup ()

void	init_heartbeat_period ()

void	init_checksum_alg ()

int	check_start_file ()
	Check if the requested binlog file and position are valid. More...

const char *	log_read_error_msg (Binlog_read_error::Error_type error)
	Transform read error numbers to error messages. More...

int	send_binlog (File_reader &reader, my_off_t start_pos)
	It dumps a binlog file. More...

int	send_events (File_reader &reader, my_off_t end_pos)
	It sends some events in a binlog file to the client. More...

std::pair< my_off_t, int >	get_binlog_end_pos (File_reader &reader)
	It gets the end position of the binlog file. More...

int	has_previous_gtid_log_event (File_reader &reader, bool *found)
	It checks if a binlog file has Previous_gtid_log_event. More...

int	fake_rotate_event (const char *next_log_file, my_off_t log_pos)
	It sends a faked rotate event which does not exist physically in any binlog to the slave. More...

int	send_format_description_event (File_reader &reader, my_off_t start_pos)
	When starting to dump a binlog file, Format_description_log_event is read and sent first. More...

int	send_heartbeat_event_v1 (my_off_t log_pos)
	It sends a heartbeat to the client. More...

int	send_heartbeat_event_v2 (my_off_t log_pos)
	It sends a heartbeat to the client, for the cases when the flag USE_HEARTBEAT_EVENT_V2 is set. More...

int	send_heartbeat_event (my_off_t log_pos)
	Checks if the heartbeat_version flag is set or not, and call the correct send_heartbeat_method accordingly. More...

int	read_event (File_reader &reader, uchar *event_ptr, uint32 event_len)
	It reads an event from binlog file. More...

bool	check_event_type (mysql::binlog::event::Log_event_type type, const char *log_file, my_off_t log_pos)
	Check if it is allowed to send this event type. More...

bool	skip_event (const uchar *event_ptr, bool in_exclude_group)
	It checks if the event is in m_exclude_gtid. More...

void	calc_event_checksum (uchar *event_ptr, size_t event_len)

int	flush_net ()

int	send_packet ()

int	send_packet_and_flush ()

int	before_send_hook (const char *log_file, my_off_t log_pos)

int	after_send_hook (const char *log_file, my_off_t log_pos)

int	reset_transmit_packet (ushort flags, size_t event_len=0)

int	wait_new_events (my_off_t log_pos)
	It waits until receiving an update_cond signal. More...

int	wait_with_heartbeat (my_off_t log_pos)

int	wait_without_heartbeat (my_off_t log_pos)

int	check_event_count ()

bool	has_error ()

void	set_error (int errorno, const char *errmsg)

void	set_unknown_error (const char *errmsg)

void	set_fatal_error (const char *errmsg)

bool	is_fatal_error ()

bool	event_checksum_on ()

void	set_last_pos (my_off_t log_pos)

void	set_last_file (const char *log_file)

bool	grow_packet (size_t extra_size)
	This function SHALL grow the buffer of the packet if needed. More...

bool	shrink_packet ()
	This function SHALL shrink the size of the buffer used. More...

size_t	calc_grow_buffer_size (size_t current_size, size_t min_size)
	Helper function to recalculate a new size for the growing buffer. More...

void	calc_shrink_buffer_size (size_t current_size)
	Helper function to recalculate the new size for the m_new_shrink_size. More...

Private Attributes
THD *	m_thd

String &	m_packet

const char *	m_start_file

my_off_t	m_start_pos

Gtid_set *	m_exclude_gtid

bool	m_using_gtid_protocol

bool	m_check_previous_gtid_event

bool	m_gtid_clear_fd_created_flag

Log_info	m_linfo

mysql::binlog::event::enum_binlog_checksum_alg	m_event_checksum_alg

mysql::binlog::event::enum_binlog_checksum_alg	m_slave_checksum_alg

std::chrono::nanoseconds	m_heartbeat_period

std::chrono::nanoseconds	m_last_event_sent_ts

bool	m_wait_new_events

Diagnostics_area	m_diag_area

char	m_errmsg_buf [MYSQL_ERRMSG_SIZE]

const char *	m_errmsg

int	m_errno

char	m_last_file_buf [FN_REFLEN]

const char *	m_last_file

my_off_t	m_last_pos

ushort	m_half_buffer_size_req_counter

size_t	m_new_shrink_size

uint32	m_flag

bool	m_observe_transmission

bool	m_transmit_started

mysql::binlog::event::Log_event_type	m_prev_event_type
	Type of the previously processed event. More...

int	m_event_count

Static Private Attributes
static const uint32	PACKET_MAX_SIZE = UINT_MAX32

static const ushort	PACKET_SHRINK_COUNTER_THRESHOLD = 100

static const uint32	PACKET_MIN_SIZE = 4096
	The minimum size of the buffer. More...

static const float	PACKET_GROW_FACTOR = 2.0
	How much to grow the buffer each time we need to accommodate more bytes than it currently can hold. More...

static const float	PACKET_SHRINK_FACTOR = 0.5
	The dual of PACKET_GROW_FACTOR. More...

Detailed Description

The major logic of dump thread is implemented in this class.

It sends required binlog events to clients according to their requests.

Member Typedef Documentation

◆ File_reader

typedef Basic_binlog_file_reader<Binlog_ifile, Binlog_event_data_istream, Binlog_event_object_istream, Event_allocator> Binlog_sender::File_reader

private

Constructor & Destructor Documentation

◆ Binlog_sender()

Binlog_sender::Binlog_sender	(	THD *	thd,
		const char *	start_file,
		my_off_t	start_pos,
		Gtid_set *	exclude_gtids,
		uint32	flag
	)

◆ ~Binlog_sender()

Binlog_sender::~Binlog_sender ( )

default

Member Function Documentation

◆ after_send_hook()

int Binlog_sender::after_send_hook	(	const char *	log_file,
		my_off_t	log_pos
	)

inlineprivate

◆ before_send_hook()

int Binlog_sender::before_send_hook	(	const char *	log_file,
		my_off_t	log_pos
	)

inlineprivate

◆ calc_event_checksum()

void Binlog_sender::calc_event_checksum	(	uchar *	event_ptr,
		size_t	event_len
	)

inlineprivate

◆ calc_grow_buffer_size()

size_t Binlog_sender::calc_grow_buffer_size	(	size_t	current_size,
		size_t	min_size
	)

inlineprivate

Helper function to recalculate a new size for the growing buffer.

Parameters

current_size	The baseline (for instance, the current buffer size).
min_size	The resulting buffer size, needs to be at least as large as this parameter states.

Returns: The new buffer size, or 0 in the case of an error.

◆ calc_shrink_buffer_size()

void Binlog_sender::calc_shrink_buffer_size ( size_t current_size )

private

Helper function to recalculate the new size for the m_new_shrink_size.

Parameters

current_size The baseline (for instance, the current buffer size).

◆ check_event_count()

int Binlog_sender::check_event_count ( )

inlineprivate

◆ check_event_type()

bool Binlog_sender::check_event_type	(	mysql::binlog::event::Log_event_type	type,
		const char *	log_file,
		my_off_t	log_pos
	)

private

Check if it is allowed to send this event type.

The following are disallowed:

GTID_MODE=ON and type==ANONYMOUS_GTID_LOG_EVENT
AUTO_POSITION=1 and type==ANONYMOUS_GTID_LOG_EVENT
GTID_MODE=OFF and type==GTID_LOG_EVENT

Parameters

type	The event type.
log_file	The binary log file (used in error messages).
log_pos	The binary log position (used in error messages).

Return values

true	The event is not allowed. In this case, this function calls set_fatal_error().
false	The event is allowed.

◆ check_start_file()

int Binlog_sender::check_start_file ( )

private

Check if the requested binlog file and position are valid.

◆ cleanup()

void Binlog_sender::cleanup ( )

private

◆ event_checksum_on()

bool Binlog_sender::event_checksum_on ( )

inlineprivate

◆ fake_rotate_event()

int Binlog_sender::fake_rotate_event	(	const char *	next_log_file,
		my_off_t	log_pos
	)

private

It sends a faked rotate event which does not exist physically in any binlog to the slave.

It contains the name of the binlog we are going to send to the slave.

Faked rotate event is required in a few cases, so slave can know which binlog the following events are from.

The binlog file slave requested is Empty. E.g. "CHANGE REPLICATION SOURCE TO SOURCE_LOG_FILE='', SOURCE_LOG_POS=4", etc.
The position slave requested is exactly the end of a binlog file.
Previous binlog file does not include a rotate event. It happens when server is shutdown and restarted.
The previous binary log was GTID-free (does not contain a Previous_gtids_log_event) and the slave is connecting using the GTID protocol.

Parameters

[in]	next_log_file	The name of the binlog file will be sent after the rotate event.
[in]	log_pos	The start position of the binlog file.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ flush_net()

int Binlog_sender::flush_net ( )

inlineprivate

◆ get_binlog_end_pos()

std::pair< my_off_t, int > Binlog_sender::get_binlog_end_pos ( File_reader & reader )

private

It gets the end position of the binlog file.

Parameters

[in] reader File_reader of binlog will be checked

Returns

Pair :

Binlog end position - will be set to the end position of the reading binlog file. If this is an inactive file, it will be set to 0.
Status code - 0 (success), 1 (end execution)

Note: Function is responsible for flushing the net buffer, flushes before waiting and before returning 1 which means end of the execution (normal/error)

◆ grow_packet()

bool Binlog_sender::grow_packet ( size_t extra_size )

inlineprivate

This function SHALL grow the buffer of the packet if needed.

If the buffer used for the packet is large enough to accommodate the requested extra bytes, then this function does not do anything.

On the other hand, if the requested size is bigger than the available free bytes in the buffer, the buffer is extended by a constant factor (PACKET_GROW_FACTOR).

Parameters

extra_size The size in bytes that the caller wants to add to the buffer.

Returns: true if an error occurred, false otherwise.

◆ has_error()

bool Binlog_sender::has_error ( )

inlineprivate

◆ has_previous_gtid_log_event()

int Binlog_sender::has_previous_gtid_log_event	(	File_reader &	reader,
		bool *	found
	)

private

It checks if a binlog file has Previous_gtid_log_event.

Parameters

[in]	reader	File_reader of binlog will be checked
[out]	found	Found Previous_gtid_log_event or not

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ init()

void Binlog_sender::init ( )

private

◆ init_checksum_alg()

void Binlog_sender::init_checksum_alg ( )

private

◆ init_heartbeat_period()

void Binlog_sender::init_heartbeat_period ( )

private

◆ is_fatal_error()

bool Binlog_sender::is_fatal_error ( )

inlineprivate

◆ log_read_error_msg()

const char * Binlog_sender::log_read_error_msg ( Binlog_read_error::Error_type error )

private

Transform read error numbers to error messages.

◆ read_event()

int Binlog_sender::read_event	(	File_reader &	reader,
		uchar **	event_ptr,
		uint32 *	event_len
	)

inlineprivate

It reads an event from binlog file.

this function can set event_ptr either a valid buffer pointer or nullptr. nullptr means it arrives at the end of the binlog file if no error happens.

Parameters

[in]	reader	File_reader of the binlog file.
[out]	event_ptr	The buffer used to store the event.
[out]	event_len	Length of the event.

Return values

0	Succeed
1	Fail

◆ reset_transmit_packet()

int Binlog_sender::reset_transmit_packet	(	ushort	flags,
		size_t	event_len = `0`
	)

inlineprivate

◆ run()

void Binlog_sender::run ( )

It checks the dump request and sends events to the client until it finish all events(for mysqlbinlog) or encounters an error.

◆ send_binlog()

int Binlog_sender::send_binlog	(	File_reader &	reader,
		my_off_t	start_pos
	)

private

It dumps a binlog file.

Events are read and sent one by one. If it need to wait for new events, it will wait after already reading all events in the active log file.

Parameters

[in]	reader	File_reader of binlog will be sent
[in]	start_pos	Position requested by the slave's IO thread. Only the events after the position are sent.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_events()

int Binlog_sender::send_events	(	File_reader &	reader,
		my_off_t	end_pos
	)

private

It sends some events in a binlog file to the client.

Parameters

[in]	reader	File_reader of binlog will be sent
[in]	end_pos	Only the events before end_pos are sent

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_format_description_event()

int Binlog_sender::send_format_description_event	(	File_reader &	reader,
		my_off_t	start_pos
	)

private

When starting to dump a binlog file, Format_description_log_event is read and sent first.

If the requested position is after Format_description_log_event, log_pos field in the first Format_description_log_event has to be set to 0. So the slave will not increment its master's binlog position.

Parameters

[in]	reader	File_reader of the binlog will be dumpped
[in]	start_pos	Position requested by the slave's IO thread. Only the events after the position are sent.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_heartbeat_event()

int Binlog_sender::send_heartbeat_event ( my_off_t log_pos )

private

Checks if the heartbeat_version flag is set or not, and call the correct send_heartbeat_method accordingly.

Parameters

[in] log_pos The log position that events before it are sent.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_heartbeat_event_v1()

int Binlog_sender::send_heartbeat_event_v1 ( my_off_t log_pos )

private

It sends a heartbeat to the client.

Parameters

[in] log_pos The log position that events before it are sent.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_heartbeat_event_v2()

int Binlog_sender::send_heartbeat_event_v2 ( my_off_t log_pos )

private

It sends a heartbeat to the client, for the cases when the flag USE_HEARTBEAT_EVENT_V2 is set.

Parameters

[in] log_pos The log position that events before it are sent.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ send_packet()

int Binlog_sender::send_packet ( )

inlineprivate

◆ send_packet_and_flush()

int Binlog_sender::send_packet_and_flush ( )

inlineprivate

◆ set_error()

void Binlog_sender::set_error	(	int	errorno,
		const char *	errmsg
	)

inlineprivate

◆ set_fatal_error()

void Binlog_sender::set_fatal_error ( const char * errmsg )

inlineprivate

◆ set_last_file()

void Binlog_sender::set_last_file ( const char * log_file )

inlineprivate

◆ set_last_pos()

void Binlog_sender::set_last_pos ( my_off_t log_pos )

inlineprivate

◆ set_prev_event_type()

void Binlog_sender::set_prev_event_type ( mysql::binlog::event::Log_event_type type )

inline

Sets the value of the previously processed event.

Parameters

type	The last processed event type.

◆ set_unknown_error()

void Binlog_sender::set_unknown_error ( const char * errmsg )

inlineprivate

◆ shrink_packet()

bool Binlog_sender::shrink_packet ( )

inlineprivate

This function SHALL shrink the size of the buffer used.

If less than half of the buffer was used in the last N (PACKET_SHRINK_COUNTER_THRESHOLD) consecutive times this function was called, then the buffer gets shrunk by a constant factor (PACKET_SHRINK_FACTOR).

The buffer is never shrunk less than a minimum size (PACKET_MIN_SIZE).

◆ skip_event()

bool Binlog_sender::skip_event	(	const uchar *	event_ptr,
		bool	in_exclude_group
	)

inlineprivate

It checks if the event is in m_exclude_gtid.

Clients may request to exclude some GTIDs. The events include in the GTID groups will be skipped. We call below events sequence as a goup, Gtid_log_event BEGIN ... COMMIT or ROLLBACK

or Gtid_log_event DDL statement

Parameters

[in]	event_ptr	Buffer of the event
[in]	in_exclude_group	If it is in a exclude group

Returns: It returns true if it should be skipped, otherwise false is turned.

◆ stop_waiting_for_update()

bool Binlog_sender::stop_waiting_for_update ( my_off_t log_pos ) const

private

Checks whether thread should continue awaiting new events.

Parameters

log_pos Last processed (sent) event id

◆ wait_new_events()

int Binlog_sender::wait_new_events ( my_off_t log_pos )

private

It waits until receiving an update_cond signal.

It will send heartbeat periodically if m_heartbeat_period is set.

Parameters

[in] log_pos The end position of the last event it already sent. It is required by heartbeat events.

Returns: It returns 0 if succeeds, otherwise 1 is returned.

◆ wait_with_heartbeat()

int Binlog_sender::wait_with_heartbeat ( my_off_t log_pos )

inlineprivate

◆ wait_without_heartbeat()

int Binlog_sender::wait_without_heartbeat ( my_off_t log_pos )

inlineprivate

Member Data Documentation

◆ m_check_previous_gtid_event

bool Binlog_sender::m_check_previous_gtid_event

private

◆ m_diag_area

Diagnostics_area Binlog_sender::m_diag_area

private

◆ m_errmsg

const char* Binlog_sender::m_errmsg

private

◆ m_errmsg_buf

char Binlog_sender::m_errmsg_buf[MYSQL_ERRMSG_SIZE]

private

◆ m_errno

int Binlog_sender::m_errno

private

◆ m_event_checksum_alg

mysql::binlog::event::enum_binlog_checksum_alg Binlog_sender::m_event_checksum_alg

private

◆ m_event_count

int Binlog_sender::m_event_count

private

◆ m_exclude_gtid

Gtid_set* Binlog_sender::m_exclude_gtid

private

◆ m_flag

uint32 Binlog_sender::m_flag

private

◆ m_gtid_clear_fd_created_flag

bool Binlog_sender::m_gtid_clear_fd_created_flag

private

◆ m_half_buffer_size_req_counter

ushort Binlog_sender::m_half_buffer_size_req_counter

private

◆ m_heartbeat_period

std::chrono::nanoseconds Binlog_sender::m_heartbeat_period

private

◆ m_last_event_sent_ts

std::chrono::nanoseconds Binlog_sender::m_last_event_sent_ts

private

◆ m_last_file

const char* Binlog_sender::m_last_file

private

◆ m_last_file_buf

char Binlog_sender::m_last_file_buf[FN_REFLEN]

private

◆ m_last_pos

my_off_t Binlog_sender::m_last_pos

private

◆ m_linfo

Log_info Binlog_sender::m_linfo

private

◆ m_new_shrink_size

size_t Binlog_sender::m_new_shrink_size

private

◆ m_observe_transmission

bool Binlog_sender::m_observe_transmission

private

◆ m_packet

String& Binlog_sender::m_packet

private

◆ m_prev_event_type

mysql::binlog::event::Log_event_type Binlog_sender::m_prev_event_type

private

Type of the previously processed event.

◆ m_slave_checksum_alg

mysql::binlog::event::enum_binlog_checksum_alg Binlog_sender::m_slave_checksum_alg

private

◆ m_start_file

const char* Binlog_sender::m_start_file

private

◆ m_start_pos

my_off_t Binlog_sender::m_start_pos

private

◆ m_thd

THD* Binlog_sender::m_thd

private

◆ m_transmit_started

bool Binlog_sender::m_transmit_started

private

◆ m_using_gtid_protocol

bool Binlog_sender::m_using_gtid_protocol

private

◆ m_wait_new_events

bool Binlog_sender::m_wait_new_events

private

◆ PACKET_GROW_FACTOR

const float Binlog_sender::PACKET_GROW_FACTOR = 2.0

staticprivate

How much to grow the buffer each time we need to accommodate more bytes than it currently can hold.

◆ PACKET_MAX_SIZE

const uint32 Binlog_sender::PACKET_MAX_SIZE = UINT_MAX32

staticprivate

◆ PACKET_MIN_SIZE

const uint32 Binlog_sender::PACKET_MIN_SIZE = 4096

staticprivate

The minimum size of the buffer.

◆ PACKET_SHRINK_COUNTER_THRESHOLD

const ushort Binlog_sender::PACKET_SHRINK_COUNTER_THRESHOLD = 100

staticprivate

◆ PACKET_SHRINK_FACTOR

const float Binlog_sender::PACKET_SHRINK_FACTOR = 0.5

staticprivate

The dual of PACKET_GROW_FACTOR.

How much to shrink the buffer each time it is deemed to being underused.

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

sql/rpl_binlog_sender.h
sql/rpl_binlog_sender.cc

Classes

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Typedef Documentation

◆ File_reader

Constructor & Destructor Documentation

◆ Binlog_sender()

◆ ~Binlog_sender()

Member Function Documentation

◆ after_send_hook()

◆ before_send_hook()

◆ calc_event_checksum()

◆ calc_grow_buffer_size()

◆ calc_shrink_buffer_size()

◆ check_event_count()

◆ check_event_type()

◆ check_start_file()

◆ cleanup()

◆ event_checksum_on()

◆ fake_rotate_event()

◆ flush_net()

◆ get_binlog_end_pos()

◆ grow_packet()

◆ has_error()

◆ has_previous_gtid_log_event()

◆ init()

◆ init_checksum_alg()

◆ init_heartbeat_period()

◆ is_fatal_error()

◆ log_read_error_msg()

◆ read_event()

◆ reset_transmit_packet()

◆ run()

◆ send_binlog()

◆ send_events()

◆ send_format_description_event()

◆ send_heartbeat_event()

◆ send_heartbeat_event_v1()

◆ send_heartbeat_event_v2()

◆ send_packet()

◆ send_packet_and_flush()

◆ set_error()

◆ set_fatal_error()

◆ set_last_file()

◆ set_last_pos()

◆ set_prev_event_type()

◆ set_unknown_error()

◆ shrink_packet()

◆ skip_event()

◆ stop_waiting_for_update()

◆ wait_new_events()

◆ wait_with_heartbeat()

◆ wait_without_heartbeat()

Member Data Documentation

◆ m_check_previous_gtid_event

◆ m_diag_area

◆ m_errmsg

◆ m_errmsg_buf

◆ m_errno

◆ m_event_checksum_alg

◆ m_event_count

◆ m_exclude_gtid

◆ m_flag

◆ m_gtid_clear_fd_created_flag

◆ m_half_buffer_size_req_counter

◆ m_heartbeat_period

◆ m_last_event_sent_ts

◆ m_last_file

◆ m_last_file_buf

◆ m_last_pos

◆ m_linfo

◆ m_new_shrink_size

◆ m_observe_transmission

◆ m_packet

◆ m_prev_event_type

◆ m_slave_checksum_alg