File metadata to be stored in and retrieved from the RocksDB database. More...

#include <metadata.hpp>

Public Member Functions
	Metadata (void)
	Construct a new empty Metadata object. More...

	Metadata (const std::string &serialized)
	Construct a new Metadata object from serialized string. More...

	Metadata (const Metadata &other)
	Copy construct a new Metadata object. More...

Metadata &	operator= (const Metadata &other)
	Copy assign a new Metadata object. More...

	Metadata (Metadata &&other)
	Move construct a new Metadata object. More...

Metadata &	operator= (Metadata &&other)
	Move assign a new Metadata object. More...

	~Metadata (void)=default
	Destroy the Metadata object. More...

	Metadata (std::string path, std::shared_ptr< rocksdb::DB > db, Tier *tptr=nullptr)
	Construct a new Metadata object. Try to retrieve data from db. If not found and tptr != nullptr, new metadata object is initialized and put into the database. If not found and tptr == nullptr, metadata is left undefined and not_found_ is set to true. More...

void	update (std::string relative_path, std::shared_ptr< rocksdb::DB > db, std::string *old_key=nullptr)
	Put metadata into database with relative_path as the key. More...

void	touch (void)
	Increment access_count_. More...

std::string	tier_path (void) const
	Get path to tier root. More...

void	tier_path (const std::string &path)
	Set path to tier root. More...

bool	pinned (void) const
	Test if metadata has pinned flag set. More...

void	pinned (bool val)
	Set pinned flag. More...

double	popularity (void) const
	Get popularity. More...

bool	not_found (void) const
	Test if metadata was found in database. More...

std::string	dump_stats (void) const
	Return metadata as formatted string. More...

Private Member Functions
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
	Serialize method for boost::serialize. More...

Private Attributes
uintmax_t	access_count_ = 0
	Number of times the file was accessed since last tiering. Resets to 0 after each popularity calculation. More...

double	popularity_ = MULTIPLIER * AVG_USAGE
	Moving average of file usage frequency in accesses per hour. Used to sort list of files to determine which tiers they belong in. More...

bool	not_found_ = false
	Set to true when the file metadata could not be retrieved from the database. More...

bool	pinned_ = false
	Flag to determine whether to ignore file while tiering. When true, the file stays in the tier it is in. More...

std::string	tier_path_
	The backend path of the tier. This + relative path is the real location of the file. More...

Friends
class	boost::serialization::access

class	File

class	MetadataViewer

Detailed Description

File metadata to be stored in and retrieved from the RocksDB database.

Constructor & Destructor Documentation

◆ Metadata() [1/5]

Metadata::Metadata ( void )

Construct a new empty Metadata object.

◆ Metadata() [2/5]

Metadata::Metadata ( const std::string & serialized )

Construct a new Metadata object from serialized string.

Parameters

serialized Serialized string representing Metadata object

◆ Metadata() [3/5]

Metadata::Metadata ( const Metadata & other )

Copy construct a new Metadata object.

Parameters

other

◆ Metadata() [4/5]

Metadata::Metadata ( Metadata && other )

Move construct a new Metadata object.

Parameters

other

◆ ~Metadata()

Metadata::~Metadata ( void )

default

Destroy the Metadata object.

◆ Metadata() [5/5]

Metadata::Metadata	(	std::string	path,
		std::shared_ptr< rocksdb::DB >	db,
		Tier *	tptr = `nullptr`
	)

Construct a new Metadata object. Try to retrieve data from db. If not found and tptr != nullptr, new metadata object is initialized and put into the database. If not found and tptr == nullptr, metadata is left undefined and not_found_ is set to true.

Parameters

path
db
tptr

Member Function Documentation

◆ dump_stats()

std::string Metadata::dump_stats ( void ) const

Return metadata as formatted string.

Returns: std::string

◆ not_found()

bool Metadata::not_found ( void ) const

Test if metadata was found in database.

Returns: true metadata was not found; false metadata was found

◆ operator=() [1/2]

Metadata & Metadata::operator= ( const Metadata & other )

Copy assign a new Metadata object.

Parameters

other

Returns: Metadata&

◆ operator=() [2/2]

Metadata & Metadata::operator= ( Metadata && other )

Move assign a new Metadata object.

Parameters

other

Returns: Metadata&

◆ pinned() [1/2]

void Metadata::pinned ( bool val )

Set pinned flag.

Parameters

val

◆ pinned() [2/2]

bool Metadata::pinned ( void ) const

Test if metadata has pinned flag set.

Returns: true File corresponding to metadata is pinned; false File corresponding to metadata is not pinned

◆ popularity()

double Metadata::popularity ( void ) const

Get popularity.

Returns: double Popularity of file

◆ serialize()

template<class Archive >

void Metadata::serialize	(	Archive &	ar,
		const unsigned int	version
	)

inlineprivate

Serialize method for boost::serialize.

Template Parameters

Archive Template type

Parameters

ar	Internal boost::serialize object
version	boost::serialize version (unused)

◆ tier_path() [1/2]

void Metadata::tier_path ( const std::string & path )

Set path to tier root.

Parameters

path

◆ tier_path() [2/2]

std::string Metadata::tier_path ( void ) const

Get path to tier root.

Returns: std::string

◆ touch()

void Metadata::touch ( void )

Increment access_count_.

◆ update()

void Metadata::update	(	std::string	relative_path,
		std::shared_ptr< rocksdb::DB >	db,
		std::string *	old_key = `nullptr`
	)

Put metadata into database with relative_path as the key.

Parameters

relative_path	Database key
db	Pointer to RocksDB database
old_key	string pointer to old key to remove if not nullptr

Member Data Documentation

◆ access_count_

uintmax_t Metadata::access_count_ = 0

private

Number of times the file was accessed since last tiering. Resets to 0 after each popularity calculation.

◆ not_found_

bool Metadata::not_found_ = false

private

Set to true when the file metadata could not be retrieved from the database.

◆ pinned_

bool Metadata::pinned_ = false

private

Flag to determine whether to ignore file while tiering. When true, the file stays in the tier it is in.

◆ popularity_

double Metadata::popularity_ = MULTIPLIER * AVG_USAGE

private

Moving average of file usage frequency in accesses per hour. Used to sort list of files to determine which tiers they belong in.

◆ tier_path_

std::string Metadata::tier_path_

private

The backend path of the tier. This + relative path is the real location of the file.

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

src/incl/metadata.hpp
src/impl/autotierfs/metadata.cpp

Public Member Functions

Private Member Functions

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Metadata() [1/5]

◆ Metadata() [2/5]

◆ Metadata() [3/5]

◆ Metadata() [4/5]

◆ ~Metadata()

◆ Metadata() [5/5]

Member Function Documentation

◆ dump_stats()

◆ not_found()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ pinned() [1/2]

◆ pinned() [2/2]

◆ popularity()

◆ serialize()

◆ tier_path() [1/2]

◆ tier_path() [2/2]

◆ touch()

◆ update()

Member Data Documentation

◆ access_count_

◆ not_found_

◆ pinned_

◆ popularity_

◆ tier_path_