This class implements LZ4 compression. More...

#include <gcs_message_stage_lz4.h>

Inheritance diagram for Gcs_message_stage_lz4:

Public Member Functions
Gcs_message_stage::stage_status	skip_apply (uint64_t const &original_payload_size) const override
	Check if the apply operation which affects outgoing packets should be executed (i.e. More...

std::unique_ptr< Gcs_stage_metadata >	get_stage_header () override

	Gcs_message_stage_lz4 ()
	Creates an instance of the stage with the default threshold in bytes set. More...

	Gcs_message_stage_lz4 (bool enabled, unsigned long long compress_threshold)
	Creates an instance of the stage with the given threshold in bytes. More...

	~Gcs_message_stage_lz4 () override=default

Stage_code	get_stage_code () const override
	Return the unique stage code. More...

void	set_threshold (unsigned long long threshold)
	Sets the threshold in bytes after which compression kicks in. More...

Public Member Functions inherited from Gcs_message_stage
	Gcs_message_stage ()

	Gcs_message_stage (bool enabled)

virtual	~Gcs_message_stage ()=default

std::pair< bool, std::vector< Gcs_packet > >	apply (Gcs_packet &&packet)
	Apply some transformation to the outgoing packet, and return a set of one, or more, transformed packets. More...

std::pair< Gcs_pipeline_incoming_result, Gcs_packet >	revert (Gcs_packet &&packet)
	Revert some transformation from the incoming packet, and return one, or none, transformed packet. More...

bool	is_enabled () const
	Return whether the message stage is enabled or not. More...

virtual bool	update_members_information (const Gcs_member_identifier &, const Gcs_xcom_nodes &)
	Update the list of members in the group as this may be required by some stages in the communication pipeline. More...

virtual Gcs_xcom_synode_set	get_snapshot () const

void	set_enabled (bool is_enabled)
	Enable or disable the message stage. More...

Static Public Member Functions
static constexpr unsigned long long	max_input_compression () noexcept
	Return the maximum payload size in bytes that can be compressed. More...

Static Public Attributes
static constexpr unsigned long long	DEFAULT_THRESHOLD = 1024
	The default threshold value in bytes. More...

Protected Member Functions
std::pair< bool, std::vector< Gcs_packet > >	apply_transformation (Gcs_packet &&packet) override
	Implements the logic of this stage's transformation to the packet, and returns a set of one, or more, transformed packets. More...

std::pair< Gcs_pipeline_incoming_result, Gcs_packet >	revert_transformation (Gcs_packet &&packet) override
	Implements the logic to revert this stage's transformation to the packet, and returns one, or none, transformed packet. More...

Gcs_message_stage::stage_status	skip_revert (const Gcs_packet &packet) const override
	Check if the revert operation which affects incoming packets should be executed (i.e. More...

Protected Member Functions inherited from Gcs_message_stage
void	encode (unsigned char *header, unsigned short header_length, unsigned long long old_payload_length)
	Encode the fixed part of the associated dynamic header information into the header buffer. More...

void	decode (const unsigned char header, unsigned short header_length, unsigned long long *old_payload_length)
	Decode the fixed part of the associated dynamic header information from the header buffer. More...

Private Attributes
unsigned long long	m_threshold
	This marks the threshold in bytes above which a message gets compressed. More...

Additional Inherited Members
Public Types inherited from Gcs_message_stage
enum class	stage_status : unsigned int { apply , skip , abort }

Detailed Description

This class implements LZ4 compression.

It is a stateless service class, thence it is thread safe.

Constructor & Destructor Documentation

◆ Gcs_message_stage_lz4() [1/2]

Gcs_message_stage_lz4::Gcs_message_stage_lz4 ( )

inlineexplicit

Creates an instance of the stage with the default threshold in bytes set.

◆ Gcs_message_stage_lz4() [2/2]

Gcs_message_stage_lz4::Gcs_message_stage_lz4	(	bool	enabled,
		unsigned long long	compress_threshold
	)

inlineexplicit

Creates an instance of the stage with the given threshold in bytes.

Parameters

enabled	enables this message stage
compress_threshold	messages with the payload larger than compress_threshold in bytes are compressed.

◆ ~Gcs_message_stage_lz4()

Gcs_message_stage_lz4::~Gcs_message_stage_lz4 ( )

overridedefault

Member Function Documentation

◆ apply_transformation()

std::pair< bool, std::vector< Gcs_packet > > Gcs_message_stage_lz4::apply_transformation ( Gcs_packet && packet )

overrideprotectedvirtual

Implements the logic of this stage's transformation to the packet, and returns a set of one, or more, transformed packets.

Parameters

[in] packet The packet upon which the transformation should be applied

Return values

{true,_}	If there was an error applying the transformation
{false,P}	If the transformation was successful, and produced the set of transformed packets P

Implements Gcs_message_stage.

◆ get_stage_code()

Stage_code Gcs_message_stage_lz4::get_stage_code ( ) const

inlineoverridevirtual

Return the unique stage code.

Returns: the stage code.

Implements Gcs_message_stage.

Reimplemented in Gcs_message_stage_lz4_v2, and Gcs_message_stage_lz4_v3.

◆ get_stage_header()

std::unique_ptr< Gcs_stage_metadata > Gcs_message_stage_lz4::get_stage_header ( )

overridevirtual

Implements Gcs_message_stage.

◆ max_input_compression()

static constexpr unsigned long long Gcs_message_stage_lz4::max_input_compression ( )

inlinestaticconstexprnoexcept

Return the maximum payload size in bytes that can be compressed.

◆ revert_transformation()

std::pair< Gcs_pipeline_incoming_result, Gcs_packet > Gcs_message_stage_lz4::revert_transformation ( Gcs_packet && packet )

overrideprotectedvirtual

Implements the logic to revert this stage's transformation to the packet, and returns one, or none, transformed packet.

Parameters

[in] packet The packet upon which the transformation should be reverted

Return values

{ERROR,_}	If there was an error reverting the transformation
{OK_NO_PACKET,NP}	If the transformation was reverted, but produced no packet
{OK_PACKET,P}	If the transformation was reverted, and produced the packet P

Implements Gcs_message_stage.

◆ set_threshold()

void Gcs_message_stage_lz4::set_threshold ( unsigned long long threshold )

inline

Sets the threshold in bytes after which compression kicks in.

Parameters

threshold if the payload exceeds these many bytes, then the message is compressed.

◆ skip_apply()

Gcs_message_stage::stage_status Gcs_message_stage_lz4::skip_apply ( uint64_t const & original_payload_size ) const

overridevirtual

Check if the apply operation which affects outgoing packets should be executed (i.e.

applied), skipped or aborted.

If the outcome is code apply or code skip, the stage will process or skip the message, respectively. However, if the outcome is code abort, the message will be discarded and an error will be reported thus stopping the pipeline execution.

For example, if a packet's length is less than a pre-defined threshold the packet is not compressed.

Parameters

original_payload_size The size of the packet to which the transformation should be applied.

Returns: a status specifying whether the transformation should be executed, skipped or aborted

Implements Gcs_message_stage.

◆ skip_revert()

Gcs_message_stage::stage_status Gcs_message_stage_lz4::skip_revert ( const Gcs_packet & packet ) const

overrideprotectedvirtual

Check if the revert operation which affects incoming packets should be executed (i.e.

applied), skipped or aborted.

If the outcome is code apply or code skip, the stage will process or skip the message, respectively. However, if the outcome is code abort, the message will be discarded and an error will be reported thus stopping the pipeline execution.

For example, if the packet length is greater than the maximum allowed compressed information an error is returned.

Parameters

packet The packet upon which the transformation should be applied

Returns: a status specifying whether the transformation should be executed, skipped or aborted

Implements Gcs_message_stage.

Member Data Documentation

◆ DEFAULT_THRESHOLD

constexpr unsigned long long Gcs_message_stage_lz4::DEFAULT_THRESHOLD = 1024

staticconstexpr

The default threshold value in bytes.

◆ m_threshold

unsigned long long Gcs_message_stage_lz4::m_threshold

private

This marks the threshold in bytes above which a message gets compressed.

Messages that are smaller than this threshold are not compressed.

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

plugin/group_replication/libmysqlgcs/src/bindings/xcom/gcs_message_stage_lz4.h
plugin/group_replication/libmysqlgcs/src/bindings/xcom/gcs_message_stage_lz4.cc

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Gcs_message_stage_lz4() [1/2]

◆ Gcs_message_stage_lz4() [2/2]

◆ ~Gcs_message_stage_lz4()

Member Function Documentation

◆ apply_transformation()

◆ get_stage_code()

◆ get_stage_header()

◆ max_input_compression()

◆ revert_transformation()

◆ set_threshold()

◆ skip_apply()

◆ skip_revert()

Member Data Documentation

◆ DEFAULT_THRESHOLD

◆ m_threshold