mysql::csa::Relay_log_adaptive_reader Class Reference

Iterates over relay log and returns fetchable Jobs This reader reads consecutive events from the relay log and caches events. More...

#include <relay_log_adaptive_reader.h>

Inheritance diagram for mysql::csa::Relay_log_adaptive_reader:

Public Member Functions
	Relay_log_adaptive_reader (int instance_id, Relay_log_info *rli, std::size_t max_read_event_bytes, std::size_t max_read_payload_bytes)
virtual	~Relay_log_adaptive_reader () override
	Relay_log_adaptive_reader (const Relay_log_adaptive_reader &)=delete
Relay_log_adaptive_reader &	operator= (const Relay_log_adaptive_reader &)=delete
	Relay_log_adaptive_reader (Relay_log_adaptive_reader &&)=delete
Relay_log_adaptive_reader &	operator= (Relay_log_adaptive_reader &&)=delete
Job_ptr	read () override
	Reads the next Job (full transaction) from the relay log and supplies a fetchable job object. More...
bool	is_stopped () const override
	Checks whether CSA is stopped. More...
bool	is_error () const override
	Checks whether reader errored out True - reader errored out. More...
void	stop () override
	Awakes and stops the reader. More...
Public Member Functions inherited from mysql::csa::Reader
virtual	~Reader ()=default
	Destructor. More...

Private Types
using	Transaction_boundary_parser = mysql::binlog::event::Transaction_boundary_parser

Private Member Functions
void	tune ()
	Tunes reader parameters based on CSA statistics. More...

Private Attributes
Relay_log_info *	m_rli {nullptr}
	Pointer to the relay log context of applier thread that launches CSA. More...
Event_reader_controller *	m_reader {nullptr}
	Applier reader, object used to read event METADATA (non owning pointer) More...
Log_purge_controller_sptr	m_shared_controller
	Owning pointer of applier reader. More...
Relay_log_deleter_handle	m_delete_handler {nullptr}
	Deleter for the current file. More...
Log_prefetcher_sptr	m_prefetcher
std::shared_ptr< Log_event >	m_current_fde
	Current FDE pointer. Source's FDEs are attached to transactions. More...
Transaction_boundary_parser	m_transaction_boundary_parser
std::shared_ptr< Fetchable_transaction >	m_active_fetchable_transaction
Event_file_metadata	m_start_batch_metadata
Reader_controller_read_type	m_read_type {Reader_controller_read_type::event}
Reader_controller_read_type	m_next_read_type
Event_set_fetchable_cache *	m_open_cache_batch {nullptr}
Event_set_fetchable_relay_log *	m_open_stream_batch {nullptr}
std::size_t	m_current_transaction_max_event_length {0}
bool	m_is_in_trx {false}
int64_t	m_prev_seq {-1}
	Previous sequence number recorded to validate timestamps. More...
bool	m_is_error {false}
	Internal error flag. More...
bool	m_stopped {false}
	Stop flag, set externally or by reached until condition. More...
unsigned int	m_instance_id {0}
	Unique instance id for statistics monitoring. More...
scheduler::Statistics_instance_monitor_ref	m_stat_monitor
	Statistics monitoring object for the current instance. More...
Resource_instance_monitor_ref	m_resource_monitor
	Resource monitoring object for the current instance. More...
std::size_t	m_max_read_event_bytes {tune::provider_max_read_event_bytes}
	The maximum number of bytes that this reader can cache for a single transaction with decoding. More...
std::size_t	m_max_read_payload_bytes {tune::provider_max_read_payload_bytes}
	The maximum number of bytes that this reader can cache for a single transaction without decoding. More...
std::unique_ptr< Channel >	m_channel
	Owning pointer to channel object. More...
double	m_worker_min_load_threshold {0.3}
	Threshold below which we ask workers to read transactions in order to increase reader and receiver throughput. More...
double	m_worker_max_load_threshold {0.8}
	Threshold above which we go back to previous settings. More...
Sliding_window_counter	m_thp_task_exec_time {0}
	Used to calculate workers load. More...
Sliding_window_counter	m_thp_worker_exec_time {0}
	Used to calculate workers load. More...
std::chrono::time_point< std::chrono::system_clock >	m_last_tune_time
	Time point at which we tuned parameters for the last time. More...
long int	m_tune_period_ms {5000}
	We tune parameters each m_tune_period_ms milliseconds. More...

Detailed Description

Iterates over relay log and returns fetchable Jobs This reader reads consecutive events from the relay log and caches events.

When 'max_read_event_bytes' is reached for a single transaction, the reader switches to "metadata" mode. From this point, it will read only event metadata from the relay log and supply event set batches that are able to fetch themselves from the relay log on demand (durring apply)

Member Typedef Documentation

Transaction_boundary_parser

using mysql::csa::Relay_log_adaptive_reader::Transaction_boundary_parser = mysql::binlog::event::Transaction_boundary_parser

private

Constructor & Destructor Documentation

Relay_log_adaptive_reader() [1/3]

mysql::csa::Relay_log_adaptive_reader::Relay_log_adaptive_reader	(	int	instance_id,
		Relay_log_info *	rli,
		std::size_t	max_read_event_bytes,
		std::size_t	max_read_payload_bytes
	)

Parameters

instance_id	Instance (channel) id
rli	RLI for the channel
max_read_event_bytes	The maximum number of bytes in a transaction which reader can read, decode and cache
max_read_payload_bytes	The maximum number of bytes in a transaction which reader can read and cache payload

~Relay_log_adaptive_reader()

mysql::csa::Relay_log_adaptive_reader::~Relay_log_adaptive_reader ( )

overridevirtual

Relay_log_adaptive_reader() [2/3]

mysql::csa::Relay_log_adaptive_reader::Relay_log_adaptive_reader ( const Relay_log_adaptive_reader &  )

delete

Relay_log_adaptive_reader() [3/3]

mysql::csa::Relay_log_adaptive_reader::Relay_log_adaptive_reader ( Relay_log_adaptive_reader &&  )

delete

Member Function Documentation

is_error()

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

overridevirtual

Checks whether reader errored out True - reader errored out.

False - no error.

Implements mysql::csa::Reader.

is_stopped()

bool mysql::csa::Relay_log_adaptive_reader::is_stopped ( ) const

overridevirtual

Checks whether CSA is stopped.

True if stop was requested, false otherwise

Implements mysql::csa::Reader.

operator=() [1/2]

Relay_log_adaptive_reader & mysql::csa::Relay_log_adaptive_reader::operator= ( const Relay_log_adaptive_reader &  )

delete

operator=() [2/2]

Relay_log_adaptive_reader & mysql::csa::Relay_log_adaptive_reader::operator= ( Relay_log_adaptive_reader &&  )

delete

read()

Job_ptr mysql::csa::Relay_log_adaptive_reader::read ( )

overridevirtual

Reads the next Job (full transaction) from the relay log and supplies a fetchable job object.

This function may block for a while in case it is reading from an active relay log and when being outside of transaction boundary.

Returns

Pointer to Job in case reading succeeded. Empty pointer in case of failure or stop of the reader

Implements mysql::csa::Reader.

stop()

void mysql::csa::Relay_log_adaptive_reader::stop ( )

overridevirtual

Awakes and stops the reader.

Implements mysql::csa::Reader.

tune()

void mysql::csa::Relay_log_adaptive_reader::tune ( )

private

Tunes reader parameters based on CSA statistics.

Member Data Documentation

m_active_fetchable_transaction

std::shared_ptr<Fetchable_transaction> mysql::csa::Relay_log_adaptive_reader::m_active_fetchable_transaction

private

m_channel

std::unique_ptr<Channel> mysql::csa::Relay_log_adaptive_reader::m_channel

private

Owning pointer to channel object.

m_current_fde

std::shared_ptr<Log_event> mysql::csa::Relay_log_adaptive_reader::m_current_fde

private

Current FDE pointer. Source's FDEs are attached to transactions.

m_current_transaction_max_event_length

std::size_t mysql::csa::Relay_log_adaptive_reader::m_current_transaction_max_event_length {0}

private

m_delete_handler

Relay_log_deleter_handle mysql::csa::Relay_log_adaptive_reader::m_delete_handler {nullptr}

private

Deleter for the current file.

m_instance_id

unsigned int mysql::csa::Relay_log_adaptive_reader::m_instance_id {0}

private

Unique instance id for statistics monitoring.

m_is_error

bool mysql::csa::Relay_log_adaptive_reader::m_is_error {false}

private

Internal error flag.

m_is_in_trx

bool mysql::csa::Relay_log_adaptive_reader::m_is_in_trx {false}

private

m_last_tune_time

std::chrono::time_point<std::chrono::system_clock> mysql::csa::Relay_log_adaptive_reader::m_last_tune_time

private

Initial value:

{
      std::chrono::system_clock::now()}

Time point at which we tuned parameters for the last time.

m_max_read_event_bytes

std::size_t mysql::csa::Relay_log_adaptive_reader::m_max_read_event_bytes {tune::provider_max_read_event_bytes}

private

The maximum number of bytes that this reader can cache for a single transaction with decoding.

When this limit is reached, reader switches to payload cache read mode.

m_max_read_payload_bytes

std::size_t mysql::csa::Relay_log_adaptive_reader::m_max_read_payload_bytes {tune::provider_max_read_payload_bytes}

private

The maximum number of bytes that this reader can cache for a single transaction without decoding.

When this limit is reached, reader switches to reading of transaction metadata

m_next_read_type

Reader_controller_read_type mysql::csa::Relay_log_adaptive_reader::m_next_read_type

private

Initial value:

{
      Reader_controller_read_type::event}

m_open_cache_batch

Event_set_fetchable_cache* mysql::csa::Relay_log_adaptive_reader::m_open_cache_batch {nullptr}

private

m_open_stream_batch

Event_set_fetchable_relay_log* mysql::csa::Relay_log_adaptive_reader::m_open_stream_batch {nullptr}

private

m_prefetcher

Log_prefetcher_sptr mysql::csa::Relay_log_adaptive_reader::m_prefetcher

private

m_prev_seq

int64_t mysql::csa::Relay_log_adaptive_reader::m_prev_seq {-1}

private

Previous sequence number recorded to validate timestamps.

m_read_type

Reader_controller_read_type mysql::csa::Relay_log_adaptive_reader::m_read_type {Reader_controller_read_type::event}

private

m_reader

Event_reader_controller* mysql::csa::Relay_log_adaptive_reader::m_reader {nullptr}

private

Applier reader, object used to read event METADATA (non owning pointer)

m_resource_monitor

Resource_instance_monitor_ref mysql::csa::Relay_log_adaptive_reader::m_resource_monitor

private

Resource monitoring object for the current instance.

m_rli

Relay_log_info* mysql::csa::Relay_log_adaptive_reader::m_rli {nullptr}

private

Pointer to the relay log context of applier thread that launches CSA.

It contains pointer to the actual relay log object needed for reading transactions

m_shared_controller

Log_purge_controller_sptr mysql::csa::Relay_log_adaptive_reader::m_shared_controller

private

Owning pointer of applier reader.

m_start_batch_metadata

Event_file_metadata mysql::csa::Relay_log_adaptive_reader::m_start_batch_metadata

private

m_stat_monitor

scheduler::Statistics_instance_monitor_ref mysql::csa::Relay_log_adaptive_reader::m_stat_monitor

private

Statistics monitoring object for the current instance.

m_stopped

bool mysql::csa::Relay_log_adaptive_reader::m_stopped {false}

private

Stop flag, set externally or by reached until condition.

m_thp_task_exec_time

Sliding_window_counter mysql::csa::Relay_log_adaptive_reader::m_thp_task_exec_time {0}

private

Used to calculate workers load.

m_thp_worker_exec_time

Sliding_window_counter mysql::csa::Relay_log_adaptive_reader::m_thp_worker_exec_time {0}

private

Used to calculate workers load.

m_transaction_boundary_parser

Transaction_boundary_parser mysql::csa::Relay_log_adaptive_reader::m_transaction_boundary_parser

private

Initial value:

{
      Transaction_boundary_parser::TRX_BOUNDARY_PARSER_APPLIER}

m_tune_period_ms

long int mysql::csa::Relay_log_adaptive_reader::m_tune_period_ms {5000}

private

We tune parameters each m_tune_period_ms milliseconds.

m_worker_max_load_threshold

double mysql::csa::Relay_log_adaptive_reader::m_worker_max_load_threshold {0.8}

private

Threshold above which we go back to previous settings.

m_worker_min_load_threshold

double mysql::csa::Relay_log_adaptive_reader::m_worker_min_load_threshold {0.3}

private

Threshold below which we ask workers to read transactions in order to increase reader and receiver throughput.

---

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

• sql/changestreams/apply/storage/relay_log/relay_log_adaptive_reader.h
• sql/changestreams/apply/storage/relay_log/relay_log_adaptive_reader.cpp