Implementation of Event_set_fetchable that fetches events from the relay log. More...

#include <event_set_fetchable_relay_log.h>

Inheritance diagram for mysql::csa::Event_set_fetchable_relay_log:

Public Types
using	Log_event_ptr = std::shared_ptr< Log_event >
	Shared pointer to a Log_event. More...

using	Return_status = mysql::utils::Return_status
	Type alias for return status. More...

using	Stream_type = ::binlog::Decompressing_event_object_istream
	Type alias for the decompressing event stream. More...

using	Stream_ptr = std::unique_ptr< Stream_type >
	Unique pointer to the decompressing stream. More...

Public Types inherited from mysql::csa::Event_set_fetchable
using	Fde_type = Format_description_log_event

using	Fde_ptr = Fde_type *

using	Log_event_ptr = std::shared_ptr< Log_event >

Public Member Functions
	Event_set_fetchable_relay_log (std::string filename, std::size_t start_file_pos, std::size_t end_file_pos, Relay_log_deleter_handle deleter, bool checksum_validation, bool is_trx, Log_event_ptr fde, bool streaming_open=false)
	Constructs an Event_set_fetchable_relay_log with relay log coordinates. More...

bool	wait_next () override
	Fetches the next event from the initialized internal stream. More...

std::optional< Managed_event >	fetch_next () override
	Fetches the next event if possible. More...

const std::string &	get_error_str () const override
	Retrieves the error message if any error occurred. More...

bool	is_done () const override
	Checks if the fetchable stream has finished without error. More...

bool	is_error () const override
	Checks if an error occurred in the fetchable stream. More...

bool	is_trx () const override
	Checks if this event set represents a transaction. More...

void	reset (bool reset_events) override
	Resets the state to allow fetching again, clearing error state. More...

void	set_success () override
	Callback notifying that task was executed successfully. More...

virtual	~Event_set_fetchable_relay_log () override
	Destructor. More...

std::string	to_string () const
	Returns a string representation of this batch's information. More...

Fde_ptr	get_fde () override
	Obtains non-owning pointer to current transaction FDE. More...

void	append_event_end (std::size_t end_file_pos, bool seal_after=false)
	Appends one published event boundary for stream-open batch. More...

void	seal_stream ()
	Seals stream-open batch. No more events will be appended. More...

void	set_stream_truncated ()
	Marks stream-open batch as truncated and wakes blocked readers. More...

Public Member Functions inherited from mysql::csa::Event_set_fetchable
virtual	~Event_set_fetchable ()=default
	Sets the end of the stream if needed. More...

Private Member Functions
bool	decompressing () const
	Checks if currently decompressing the internal stream (TPLE). More...

std::optional< Managed_event >	fetch_from_stream ()
	Fetches the next event from the stream. More...

bool	wait_for_event_availability ()
	Waits until stream has at least one more event available. More...

void	safe_close_reader ()
	Safely closes the reader if it is open. More...

void	safe_open_reader ()
	Safely opens the reader (closes if already open and reopens). More...

void	start_reading ()
	Starts reading from the file by opening it and creating the input stream. More...

Private Attributes
bool	m_is_initialized = false
	Flag indicating if the reader is open. More...

bool	m_is_done = false
	Flag indicating if processing is done (finished or error). More...

std::string	m_file_name {""}
	Name of the relay log file to read from. More...

std::size_t	m_start_file_pos {0}
	Starting file position for reading. More...

std::string	m_failure_msg {""}
	Detailed error message if any. More...

Return_status	m_status
	Status of the object. More...

Relay_log_deleter_handle	m_delete_file_handle
	Handle to the relay log deleter. More...

Stream_ptr	m_input_stream
	Decompressing stream object for handling compressed events. More...

Relaylog_file_reader	m_reader
	Relay log file reader used by the decompressing stream. More...

bool	m_is_trx {false}
	Flag indicating if this is a transaction. More...

bool	m_decompressing {false}
	Flag indicating if currently decompressing an internal event (TPLE). More...

Log_event_ptr	m_fde_base {}
	owning pointer to FDE. More...

Fde_ptr	m_fde {}
	non-owning pointer to FDE. More...

std::mutex	m_stream_mutex
	Stream synchronization state. More...

std::condition_variable	m_stream_cv

std::size_t	m_published_end_file_pos {0}

bool	m_stream_open {false}

bool	m_stream_sealed {true}

bool	m_stream_truncated {false}

Detailed Description

Implementation of Event_set_fetchable that fetches events from the relay log.

If the stream is compressed, the fetching function will perform decompression. Objects of this class are created by the relay log reader and used to fetch consecutive parts of a transaction (relay log events). Typically, a transaction will contain as many event sets as the number of files it spans.

Note: Each object initializes its own reader and sets it to the position of the first event metadata it contains.

Member Typedef Documentation

◆ Log_event_ptr

using mysql::csa::Event_set_fetchable_relay_log::Log_event_ptr = std::shared_ptr<Log_event>

Shared pointer to a Log_event.

◆ Return_status

using mysql::csa::Event_set_fetchable_relay_log::Return_status = mysql::utils::Return_status

Type alias for return status.

◆ Stream_ptr

using mysql::csa::Event_set_fetchable_relay_log::Stream_ptr = std::unique_ptr<Stream_type>

Unique pointer to the decompressing stream.

◆ Stream_type

using mysql::csa::Event_set_fetchable_relay_log::Stream_type = ::binlog::Decompressing_event_object_istream

Type alias for the decompressing event stream.

Constructor & Destructor Documentation

◆ Event_set_fetchable_relay_log()

mysql::csa::Event_set_fetchable_relay_log::Event_set_fetchable_relay_log	(	std::string	filename,
		std::size_t	start_file_pos,
		std::size_t	end_file_pos,
		Relay_log_deleter_handle	deleter,
		bool	checksum_validation,
		bool	is_trx,
		Event_set_fetchable::Log_event_ptr	fde,
		bool	streaming_open = `false`
	)

Constructs an Event_set_fetchable_relay_log with relay log coordinates.

The coordinates must remain valid until the transaction is applied or deemed non-appliable. Uses a relay log deleter handler to ensure the file is not deleted while in use.

Parameters

filename	The name of the relay log file.
start_file_pos	The starting position in the file.
end_file_pos	The "end" position for this event set.
deleter	Handle to the relay log deleter.
checksum_validation	Flag to enable checksum validation.
is_trx	Flag indicating if this set represents a transaction.
fde	Shared pointer to FDE for this event set.
streaming_open	If true, this set is stream-open and accepts incremental end position updates.

◆ ~Event_set_fetchable_relay_log()

mysql::csa::Event_set_fetchable_relay_log::~Event_set_fetchable_relay_log ( )

overridevirtual

Destructor.

Member Function Documentation

◆ append_event_end()

void mysql::csa::Event_set_fetchable_relay_log::append_event_end	(	std::size_t	end_file_pos,
		bool	seal_after = `false`
	)

Appends one published event boundary for stream-open batch.

Parameters

end_file_pos	End position (exclusive) for the next available event.
seal_after	When true, the batch is sealed together with publish.

◆ decompressing()

bool mysql::csa::Event_set_fetchable_relay_log::decompressing ( ) const

private

Checks if currently decompressing the internal stream (TPLE).

Returns: true if decompressing, false otherwise.

◆ fetch_from_stream()

std::optional< Managed_event > mysql::csa::Event_set_fetchable_relay_log::fetch_from_stream ( )

private

Fetches the next event from the stream.

Returns: Managed_event or empty optional in case of stream end or error.

◆ fetch_next()

std::optional< Managed_event > mysql::csa::Event_set_fetchable_relay_log::fetch_next ( )

overridevirtual

Fetches the next event if possible.

Callers are expected to wait for availability with wait_next() first when the underlying implementation supports streaming updates.

Returns: Managed_event object or an empty optional if the stream ended (with or without error).

Implements mysql::csa::Event_set_fetchable.

◆ get_error_str()

const std::string & mysql::csa::Event_set_fetchable_relay_log::get_error_str ( ) const

overridevirtual

Retrieves the error message if any error occurred.

Returns: Const reference to the error message string.

Implements mysql::csa::Event_set_fetchable.

◆ get_fde()

Event_set_fetchable::Fde_ptr mysql::csa::Event_set_fetchable_relay_log::get_fde ( )

overridevirtual

Obtains non-owning pointer to current transaction FDE.

Returns: Non-owning pointer to FDE

Implements mysql::csa::Event_set_fetchable.

◆ is_done()

bool mysql::csa::Event_set_fetchable_relay_log::is_done ( ) const

overridevirtual

Checks if the fetchable stream has finished without error.

Returns: true if finished without error, false otherwise.

Implements mysql::csa::Event_set_fetchable.

◆ is_error()

bool mysql::csa::Event_set_fetchable_relay_log::is_error ( ) const

overridevirtual

Checks if an error occurred in the fetchable stream.

Returns: true if an error occurred, false otherwise.

Implements mysql::csa::Event_set_fetchable.

◆ is_trx()

bool mysql::csa::Event_set_fetchable_relay_log::is_trx ( ) const

overridevirtual

Checks if this event set represents a transaction.

Returns: true if it contains a transaction, false otherwise.

Implements mysql::csa::Event_set_fetchable.

◆ reset()

void mysql::csa::Event_set_fetchable_relay_log::reset ( bool reset_events )

overridevirtual

Resets the state to allow fetching again, clearing error state.

Leaves the reader closed to conserve file descriptors.

Parameters

reset_events When true events states need to be reset

Implements mysql::csa::Event_set_fetchable.

◆ safe_close_reader()

void mysql::csa::Event_set_fetchable_relay_log::safe_close_reader ( )

private

Safely closes the reader if it is open.

◆ safe_open_reader()

void mysql::csa::Event_set_fetchable_relay_log::safe_open_reader ( )

private

Safely opens the reader (closes if already open and reopens).

◆ seal_stream()

void mysql::csa::Event_set_fetchable_relay_log::seal_stream ( )

Seals stream-open batch. No more events will be appended.

◆ set_stream_truncated()

void mysql::csa::Event_set_fetchable_relay_log::set_stream_truncated ( )

Marks stream-open batch as truncated and wakes blocked readers.

◆ set_success()

void mysql::csa::Event_set_fetchable_relay_log::set_success ( )

overridevirtual

Callback notifying that task was executed successfully.

Reimplemented from mysql::csa::Event_set_fetchable.

◆ start_reading()

void mysql::csa::Event_set_fetchable_relay_log::start_reading ( )

private

Starts reading from the file by opening it and creating the input stream.

◆ to_string()

std::string mysql::csa::Event_set_fetchable_relay_log::to_string ( ) const

Returns a string representation of this batch's information.

Returns: String containing basic information about the batch.

◆ wait_for_event_availability()

bool mysql::csa::Event_set_fetchable_relay_log::wait_for_event_availability ( )

private

Waits until stream has at least one more event available.

Return values

true	At least one more event can be fetched.
false	Stream is sealed/truncated/error and no more fetch is possible.

◆ wait_next()

bool mysql::csa::Event_set_fetchable_relay_log::wait_next ( )

overridevirtual

Fetches the next event from the initialized internal stream.

Returns: Managed_event or empty optional in case of stream end or error. Error can be checked with 'is_error'.

Implements mysql::csa::Event_set_fetchable.

Member Data Documentation

◆ m_decompressing

bool mysql::csa::Event_set_fetchable_relay_log::m_decompressing {false}

private

Flag indicating if currently decompressing an internal event (TPLE).

◆ m_delete_file_handle

Relay_log_deleter_handle mysql::csa::Event_set_fetchable_relay_log::m_delete_file_handle

private

Handle to the relay log deleter.

◆ m_failure_msg

std::string mysql::csa::Event_set_fetchable_relay_log::m_failure_msg {""}

private

Detailed error message if any.

◆ m_fde

Fde_ptr mysql::csa::Event_set_fetchable_relay_log::m_fde {}

private

non-owning pointer to FDE.

◆ m_fde_base

Log_event_ptr mysql::csa::Event_set_fetchable_relay_log::m_fde_base {}

private

owning pointer to FDE.

◆ m_file_name

std::string mysql::csa::Event_set_fetchable_relay_log::m_file_name {""}

private

Name of the relay log file to read from.

◆ m_input_stream

Stream_ptr mysql::csa::Event_set_fetchable_relay_log::m_input_stream

private

Decompressing stream object for handling compressed events.

◆ m_is_done

bool mysql::csa::Event_set_fetchable_relay_log::m_is_done = false

private

Flag indicating if processing is done (finished or error).

◆ m_is_initialized

bool mysql::csa::Event_set_fetchable_relay_log::m_is_initialized = false

private

Flag indicating if the reader is open.

◆ m_is_trx

bool mysql::csa::Event_set_fetchable_relay_log::m_is_trx {false}

private

Flag indicating if this is a transaction.

◆ m_published_end_file_pos

std::size_t mysql::csa::Event_set_fetchable_relay_log::m_published_end_file_pos {0}

private

◆ m_reader

Relaylog_file_reader mysql::csa::Event_set_fetchable_relay_log::m_reader

private

Relay log file reader used by the decompressing stream.

◆ m_start_file_pos

std::size_t mysql::csa::Event_set_fetchable_relay_log::m_start_file_pos {0}

private

Starting file position for reading.

◆ m_status

Return_status mysql::csa::Event_set_fetchable_relay_log::m_status

private

Status of the object.

◆ m_stream_cv

std::condition_variable mysql::csa::Event_set_fetchable_relay_log::m_stream_cv

private

◆ m_stream_mutex

std::mutex mysql::csa::Event_set_fetchable_relay_log::m_stream_mutex

mutableprivate

Stream synchronization state.

◆ m_stream_open

bool mysql::csa::Event_set_fetchable_relay_log::m_stream_open {false}

private

◆ m_stream_sealed

bool mysql::csa::Event_set_fetchable_relay_log::m_stream_sealed {true}

private

◆ m_stream_truncated

bool mysql::csa::Event_set_fetchable_relay_log::m_stream_truncated {false}

private

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

sql/changestreams/apply/storage/relay_log/event_set_fetchable_relay_log.h
sql/changestreams/apply/storage/relay_log/event_set_fetchable_relay_log.cpp

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ Log_event_ptr

◆ Return_status

◆ Stream_ptr

◆ Stream_type

Constructor & Destructor Documentation

◆ Event_set_fetchable_relay_log()

◆ ~Event_set_fetchable_relay_log()

Member Function Documentation

◆ append_event_end()

◆ decompressing()

◆ fetch_from_stream()

◆ fetch_next()

◆ get_error_str()

◆ get_fde()

◆ is_done()

◆ is_error()

◆ is_trx()

◆ reset()

◆ safe_close_reader()

◆ safe_open_reader()

◆ seal_stream()

◆ set_stream_truncated()

◆ set_success()

◆ start_reading()

◆ to_string()

◆ wait_for_event_availability()

◆ wait_next()

Member Data Documentation

◆ m_decompressing

◆ m_delete_file_handle

◆ m_failure_msg

◆ m_fde

◆ m_fde_base

◆ m_file_name

◆ m_input_stream

◆ m_is_done

◆ m_is_initialized

◆ m_is_trx

◆ m_published_end_file_pos

◆ m_reader

◆ m_start_file_pos

◆ m_status

◆ m_stream_cv

◆ m_stream_mutex

◆ m_stream_open

◆ m_stream_sealed

◆ m_stream_truncated