File database manager implementation based on skip list. More...

#include <tkrzw_dbm_skip.h>

Classes
class	Iterator
	Iterator for each record. More...

struct	TuningParameters
	Tuning parameters for the database. More...

Public Types
enum	RestoreMode : int32_t { RESTORE_DEFAULT = 0 , RESTORE_SYNC = 1 , RESTORE_READ_ONLY = 2 , RESTORE_NOOP = 3 , RESTORE_NO_SHORTCUTS = 1 << 16 , RESTORE_WITH_HARDSYNC = 1 << 17 }
	Enumeration for restore modes. More...

typedef std::vector< std::string >(*	ReducerType) (const std::string &, const std::vector< std::string > &)
	Interface of a function to reduce records of the same key in the at-random build mode. More...

Public Types inherited from tkrzw::DBM
typedef std::function< std::string_view(std::string_view, std::string_view)>	RecordLambdaType
	Lambda function type to process a record. More...

Public Member Functions
	SkipDBM ()
	Default constructor. More...

	SkipDBM (std::unique_ptr< File > file)
	Constructor with a file object. More...

	~SkipDBM ()
	Destructor. More...

	SkipDBM (const SkipDBM &rhs)=delete
	Copy and assignment are disabled. More...

SkipDBM &	operator= (const SkipDBM &rhs)=delete

Status	Open (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT) override
	Opens a database file. More...

Status	OpenAdvanced (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT, const TuningParameters &tuning_params=TuningParameters())
	Opens a database file, in an advanced way. More...

Status	Close () override
	Closes the database file. More...

Status	Process (std::string_view key, RecordProcessor *proc, bool writable) override
	Processes a record with a processor. More...

Status	Set (std::string_view key, std::string_view value, bool overwrite=true, std::string *old_value=nullptr) override
	Sets a record of a key and a value. More...

Status	Remove (std::string_view key, std::string *old_value=nullptr) override
	Removes a record of a key. More...

Status	GetByIndex (int64_t index, std::string key=nullptr, std::string value=nullptr)
	Gets the key and the value of the record of an index. More...

Status	ProcessMulti (const std::vector< std::pair< std::string_view, DBM::RecordProcessor * >> &key_proc_pairs, bool writable) override
	Processes multiple records with processors. More...

Status	ProcessFirst (RecordProcessor *proc, bool writable) override
	Processes the first record with a processor. More...

Status	ProcessEach (RecordProcessor *proc, bool writable) override
	Processes each and every record in the database with a processor. More...

Status	Count (int64_t *count) override
	Gets the number of records. More...

Status	GetFileSize (int64_t *size) override
	Gets the current file size of the database. More...

Status	GetFilePath (std::string *path) override
	Gets the path of the database file. More...

Status	GetTimestamp (double *timestamp) override
	Gets the timestamp in seconds of the last modified time. More...

Status	Clear () override
	Removes all records. More...

Status	Rebuild () override
	Rebuilds the entire database. More...

Status	RebuildAdvanced (const TuningParameters &tuning_params=TuningParameters(), bool skip_broken_records=false, bool sync_hard=false)
	Rebuilds the entire database, in an advanced way. More...

Status	ShouldBeRebuilt (bool *tobe) override
	Checks whether the database should be rebuilt. More...

Status	Synchronize (bool hard, FileProcessor *proc=nullptr) override
	Synchronizes the content of the database to the file system. More...

Status	SynchronizeAdvanced (bool hard, FileProcessor *proc=nullptr, ReducerType reducer=nullptr)
	Synchronizes the content of the database to the file system. More...

std::vector< std::pair< std::string, std::string > >	Inspect () override
	Inspects the database. More...

bool	IsOpen () const override
	Checks whether the database is open. More...

bool	IsWritable () const override
	Checks whether the database is writable. More...

bool	IsHealthy () const override
	Checks whether the database condition is healthy. More...

bool	IsAutoRestored () const
	Checks whether the database has been restored automatically. More...

bool	IsOrdered () const override
	Checks whether ordered operations are supported. More...

std::unique_ptr< DBM::Iterator >	MakeIterator () override
	Makes an iterator for each record. More...

std::unique_ptr< DBM >	MakeDBM () const override
	Makes a new DBM object of the same concrete class. More...

UpdateLogger *	GetUpdateLogger () const override
	Gets the logger to write all update operations. More...

void	SetUpdateLogger (UpdateLogger *update_logger) override
	Sets the logger to write all update operations. More...

File *	GetInternalFile () const
	Gets the pointer to the internal file object. More...

int64_t	GetEffectiveDataSize ()
	Gets the effective data size. More...

int32_t	GetDatabaseType ()
	Gets the database type. More...

Status	SetDatabaseType (uint32_t db_type)
	Sets the database type. More...

std::string	GetOpaqueMetadata ()
	Gets the opaque metadata. More...

Status	SetOpaqueMetadata (const std::string &opaque)
	Sets the opaque metadata. More...

Status	Revert ()
	Reverts all updates. More...

bool	IsUpdated ()
	Checks whether the database has been updated after being opened. More...

Status	MergeSkipDatabase (const std::string &src_path)
	Merges the contents of another skip database file. More...

Status	ValidateRecords ()
	Validates records. More...

Public Member Functions inherited from tkrzw::DBM
virtual	~DBM ()=default
	Destructor. More...

virtual Status	Process (std::string_view key, RecordLambdaType rec_lambda, bool writable)
	Processes a record with a lambda function. More...

virtual Status	Get (std::string_view key, std::string *value=nullptr)
	Gets the value of a record of a key. More...

virtual std::string	GetSimple (std::string_view key, std::string_view default_value="")
	Gets the value of a record of a key, in a simple way. More...

virtual Status	GetMulti (const std::vector< std::string_view > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with a string view vector. More...

virtual Status	GetMulti (const std::initializer_list< std::string_view > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with an initializer list. More...

virtual Status	GetMulti (const std::vector< std::string > &keys, std::map< std::string, std::string > *records)
	Gets the values of multiple records of keys, with a string vector. More...

virtual Status	SetMulti (const std::map< std::string_view, std::string_view > &records, bool overwrite=true)
	Sets multiple records, with a map of string views. More...

virtual Status	SetMulti (const std::initializer_list< std::pair< std::string_view, std::string_view >> &records, bool overwrite=true)
	Sets multiple records, with an initializer list. More...

virtual Status	SetMulti (const std::map< std::string, std::string > &records, bool overwrite=true)
	Sets multiple records, with a map of strings. More...

virtual Status	RemoveMulti (const std::vector< std::string_view > &keys)
	Removes records of keys, with a string view vector. More...

virtual Status	RemoveMulti (const std::initializer_list< std::string_view > &keys)
	Removes records of keys, with an initializer list. More...

virtual Status	RemoveMulti (const std::vector< std::string > &keys)
	Removes records of keys, with a string vector. More...

virtual Status	Append (std::string_view key, std::string_view value, std::string_view delim="")
	Appends data at the end of a record of a key. More...

virtual Status	AppendMulti (const std::map< std::string_view, std::string_view > &records, std::string_view delim="")
	Appends data to multiple records, with a map of string views. More...

virtual Status	AppendMulti (const std::initializer_list< std::pair< std::string_view, std::string_view >> &records, std::string_view delim="")
	Appends data to multiple records, with an initializer list. More...

virtual Status	AppendMulti (const std::map< std::string, std::string > &records, std::string_view delim="")
	Appends data to multiple records, with a map of strings. More...

virtual Status	CompareExchange (std::string_view key, std::string_view expected, std::string_view desired, std::string actual=nullptr, bool found=nullptr)
	Compares the value of a record and exchanges if the condition meets. More...

virtual Status	Increment (std::string_view key, int64_t increment=1, int64_t *current=nullptr, int64_t initial=0)
	Increments the numeric value of a record. More...

virtual int64_t	IncrementSimple (std::string_view key, int64_t increment=1, int64_t initial=0)
	Increments the numeric value of a record, in a simple way. More...

virtual Status	ProcessMulti (const std::vector< std::pair< std::string_view, RecordProcessor * >> &key_proc_pairs, bool writable)=0
	Processes multiple records with processors. More...

virtual Status	ProcessMulti (const std::vector< std::pair< std::string_view, RecordLambdaType >> &key_lambda_pairs, bool writable)
	Processes multiple records with lambda functions. More...

virtual Status	CompareExchangeMulti (const std::vector< std::pair< std::string_view, std::string_view >> &expected, const std::vector< std::pair< std::string_view, std::string_view >> &desired)
	Compares the values of records and exchanges if the condition meets. More...

virtual Status	Rekey (std::string_view old_key, std::string_view new_key, bool overwrite=true, bool copying=false, std::string *value=nullptr)
	Changes the key of a record. More...

virtual Status	ProcessFirst (RecordLambdaType rec_lambda, bool writable)
	Processes the first record with a lambda function. More...

virtual Status	PopFirst (std::string key=nullptr, std::string value=nullptr)
	Gets the first record and removes it. More...

virtual Status	PushLast (std::string_view value, double wtime=-1, std::string *key=nullptr)
	Adds a record with a key of the current timestamp. More...

virtual Status	ProcessEach (RecordLambdaType rec_lambda, bool writable)
	Processes each and every record in the database with a lambda function. More...

virtual int64_t	CountSimple ()
	Gets the number of records, in a simple way. More...

virtual int64_t	GetFileSizeSimple ()
	Gets the current file size of the database, in a simple way. More...

virtual std::string	GetFilePathSimple ()
	Gets the path of the database file, in a simple way. More...

virtual double	GetTimestampSimple ()
	Gets the timestamp of the last modified time, in a simple way. More...

virtual bool	ShouldBeRebuiltSimple ()
	Checks whether the database should be rebuilt, in a simple way. More...

virtual Status	CopyFileData (const std::string &dest_path, bool sync_hard=false)
	Copies the content of the database file to another file. More...

virtual Status	Export (DBM *dest_dbm)
	Exports all records to another database. More...

const std::type_info &	GetType () const
	Gets the type information of the actual class. More...

Static Public Member Functions
static std::vector< std::string >	ReduceRemove (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by removing REMOVING_VALUE and past values. More...

static std::vector< std::string >	ReduceToFirst (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by keeping the first value only. More...

static std::vector< std::string >	ReduceToSecond (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by keeping the second or first value only. More...

static std::vector< std::string >	ReduceToLast (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by keeping the last value only. More...

static std::vector< std::string >	ReduceConcat (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by concatenating all values. More...

static std::vector< std::string >	ReduceConcatWithNull (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by concatenating all values with null code. More...

static std::vector< std::string >	ReduceConcatWithTab (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by concatenating all values with tab. More...

static std::vector< std::string >	ReduceConcatWithLine (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by concatenating all values with linefeed. More...

static std::vector< std::string >	ReduceToTotal (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by totaling numeric expressions. More...

static std::vector< std::string >	ReduceToTotalBigEndian (const std::string &key, const std::vector< std::string > &values)
	Reduces the values of records of the same key by totaling big-endian binary expressions. More...

static Status	ReadMetadata (File file, int32_t cyclic_magic, int32_t pkg_major_version, int32_t pkg_minor_version, int32_t offset_width, int32_t step_unit, int32_t max_level, int32_t closure_flags, int64_t num_records, int64_t eff_data_size, int64_t file_size, int64_t mod_time, int32_t db_type, std::string opaque)
	Reads metadata from a database file. More...

static Status	RestoreDatabase (const std::string &old_file_path, const std::string &new_file_path)
	Restores a broken database as a new healthy database. More...

Static Public Attributes
static constexpr int32_t	DEFAULT_OFFSET_WIDTH = 4
	The default value of the offset width. More...

static constexpr int32_t	DEFAULT_STEP_UNIT = 4
	The default value of the step unit. More...

static constexpr int32_t	DEFAULT_MAX_LEVEL = 14
	The default value of the maximum level. More...

static constexpr int64_t	DEFAULT_SORT_MEM_SIZE = 256LL << 20
	The default value of the memory size used for sorting. More...

static constexpr int32_t	DEFAULT_MAX_CACHED_RECORDS = 65536
	The default value of the maximum cached records. More...

static constexpr int32_t	OPAQUE_METADATA_SIZE = 64
	The size of the opaque metadata. More...

static const std::string	REMOVING_VALUE
	The special removing value. More...

Static Public Attributes inherited from tkrzw::DBM
static const std::string_view	ANY_DATA
	The special string_view value to represent any data. More...

Detailed Description

File database manager implementation based on skip list.

All operations are thread-safe; Multiple threads can access the same database concurrently. Every opened database must be closed explicitly to avoid data corruption.

Member Typedef Documentation

◆ ReducerType

typedef std::vector<std::string>(* tkrzw::SkipDBM::ReducerType) (const std::string &, const std::vector< std::string > &)

Interface of a function to reduce records of the same key in the at-random build mode.

The first parameter is the key. The second parameter is a vecgtor of record values. The return value is a vector of new values which are stored in the database.

Member Enumeration Documentation

◆ RestoreMode

enum tkrzw::SkipDBM::RestoreMode : int32_t

Enumeration for restore modes.

Currently, RESTORE_DEFAULT and RESTORE_SYNC has the same meaning, and RESTORE_NO_SHORTCUTS is ignored.

Enumerator
RESTORE_DEFAULT	The default behavior: to restore as many records as possible.
RESTORE_SYNC	To restore to the last synchronized state.
RESTORE_READ_ONLY	To make the database read-only.
RESTORE_NOOP	To do nothing.
RESTORE_NO_SHORTCUTS	Additional bit to not apply shortcuts.
RESTORE_WITH_HARDSYNC	Additional bit to do physical synchronization.

Constructor & Destructor Documentation

◆ SkipDBM() [1/3]

tkrzw::SkipDBM::SkipDBM ( )

Default constructor.

MemoryMapParallelFile is used to handle the data.

◆ SkipDBM() [2/3]

tkrzw::SkipDBM::SkipDBM ( std::unique_ptr< File > file )

explicit

Constructor with a file object.

Parameters

file	The file object to handle the data. The ownership is taken.

◆ ~SkipDBM()

tkrzw::SkipDBM::~SkipDBM ( )

Destructor.

◆ SkipDBM() [3/3]

tkrzw::SkipDBM::SkipDBM ( const SkipDBM & rhs )

explicitdelete

Copy and assignment are disabled.

Member Function Documentation

◆ Open()

Status tkrzw::SkipDBM::Open	(	const std::string &	path,
		bool	writable,
		int32_t	options = `File::OPEN_DEFAULT`
	)

overridevirtual

Opens a database file.

Parameters

path	A path of the file.
writable	If true, the file is writable. If false, it is read-only.
options	Bit-sum options of File::OpenOption enums for opening the file.

Returns: The result status.

Precondition: The database is not opened.

Implements tkrzw::DBM.

◆ OpenAdvanced()

Status tkrzw::SkipDBM::OpenAdvanced	(	const std::string &	path,
		bool	writable,
		int32_t	options = `File::OPEN_DEFAULT`,
		const TuningParameters &	tuning_params = `TuningParameters()`
	)

Opens a database file, in an advanced way.

Parameters

path	A path of the file.
writable	If true, the file is writable. If false, it is read-only.
options	Bit-sum options for opening the file.
tuning_params	A structure for tuning parameters.

Returns: The result status.

Precondition: The database is not opened.

◆ Close()

Status tkrzw::SkipDBM::Close ( )

overridevirtual

Closes the database file.

Returns: The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ Process()

Status tkrzw::SkipDBM::Process	(	std::string_view	key,
		RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes a record with a processor.

Parameters

key	The key of the record.
proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

Precondition: The database is opened. The writable parameter should be consistent to the open mode.

If the specified record exists, the ProcessFull of the processor is called. Otherwise, the ProcessEmpty of the processor is called. Inserted records are not visible until the database is synchronized. The database allows duplication of keys. Duplication can be solved by the reducer applied when the database is synchronized. Removing records is implemented as inserting a special value REMOVING_VALUE, which is handled when the database is synchronized.

Implements tkrzw::DBM.

◆ Set()

Status tkrzw::SkipDBM::Set	(	std::string_view	key,
		std::string_view	value,
		bool	overwrite = `true`,
		std::string *	old_value = `nullptr`
	)

overridevirtual

Sets a record of a key and a value.

Parameters

key	The key of the record.
value	The value of the record.
overwrite	Whether to overwrite the existing value if there's a record with the same key. If true, the existing value is ovewritten by the new value. If false, the operation is given up and an error status is returned.
old_value	The pointer to a string object to contain the old value. Assignment is done even on the duplication error. If it is nullptr, it is ignored.

Returns: The result status. If overwriting is abandoned, DUPLICATION_ERROR is returned.

Precondition: The database is opened as writable.

Reimplemented from tkrzw::DBM.

◆ Remove()

Status tkrzw::SkipDBM::Remove	(	std::string_view	key,
		std::string *	old_value = `nullptr`
	)

overridevirtual

Removes a record of a key.

Parameters

key	The key of the record.

Returns: The result status. If there's no matching record, NOT_FOUND_ERROR is returned.

Parameters

old_value The pointer to a string object to contain the old value. If it is nullptr, it is ignored.

Even if there's no matching record, this doesn't report failure.

Precondition: The database is opened as writable.

Reimplemented from tkrzw::DBM.

◆ GetByIndex()

Status tkrzw::SkipDBM::GetByIndex	(	int64_t	index,
		std::string *	key = `nullptr`,
		std::string *	value = `nullptr`
	)

Gets the key and the value of the record of an index.

Parameters

index	The index of the record to retrieve.
key	The pointer to a string object to contain the record key. If it is nullptr, the key data is ignored.
value	The pointer to a string object to contain the record value. If it is nullptr, the value data is ignored.

Returns: The result status.

Precondition: The database is opened.

◆ ProcessMulti()

Status tkrzw::SkipDBM::ProcessMulti	(	const std::vector< std::pair< std::string_view, DBM::RecordProcessor * >> &	key_proc_pairs,
		bool	writable
	)

override

Processes multiple records with processors.

Parameters

key_proc_pairs	Pairs of the keys and their processor objects.
writable	True if the processors can edit the records.

Returns: The result status.

Precondition: The database is opened. The writable parameter should be consistent to the open mode.

If the specified record exists, the ProcessFull of the processor is called. Otherwise, the ProcessEmpty of the processor is called.

◆ ProcessFirst()

Status tkrzw::SkipDBM::ProcessFirst	(	RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes the first record with a processor.

Parameters

proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

Precondition: The database is opened. The writable parameter should be consistent to the open mode.

If the first record exists, the ProcessFull of the processor is called. Otherwise, this method fails and no method of the processor is called. The first record has the lowest key of all.

Implements tkrzw::DBM.

◆ ProcessEach()

Status tkrzw::SkipDBM::ProcessEach	(	RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes each and every record in the database with a processor.

Parameters

proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

Precondition: The database is opened. The writable parameter should be consistent to the open mode.

The ProcessFull of the processor is called repeatedly for each record. The ProcessEmpty of the processor is called once before the iteration and once after the iteration.

Implements tkrzw::DBM.

◆ Count()

Status tkrzw::SkipDBM::Count ( int64_t * count )

overridevirtual

Gets the number of records.

Parameters

count The pointer to an integer object to contain the result count.

Returns: The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ GetFileSize()

Status tkrzw::SkipDBM::GetFileSize ( int64_t * size )

overridevirtual

Gets the current file size of the database.

Parameters

size	The pointer to an integer object to contain the result size.

Returns: The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ GetFilePath()

Status tkrzw::SkipDBM::GetFilePath ( std::string * path )

overridevirtual

Gets the path of the database file.

Parameters

path	The pointer to a string object to contain the result path.

Returns: The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ GetTimestamp()

Status tkrzw::SkipDBM::GetTimestamp ( double * timestamp )

overridevirtual

Gets the timestamp in seconds of the last modified time.

Parameters

timestamp The pointer to a double object to contain the timestamp.

Returns: The result status.

Precondition: The database is opened.

The timestamp is updated when the database opened in the writable mode is closed or synchronized, even if no updating opertion is done.

Implements tkrzw::DBM.

◆ Clear()

Status tkrzw::SkipDBM::Clear ( )

overridevirtual

Removes all records.

Returns: The result status.

Precondition: The database is opened as writable.

Implements tkrzw::DBM.

◆ Rebuild()

Status tkrzw::SkipDBM::Rebuild ( )

overridevirtual

Rebuilds the entire database.

Returns: The result status.

Precondition: The database is opened as writable.

Rebuilding a database is useful to optimize the size of the file. All tuning parameters are succeeded or calculated implicitly.

Implements tkrzw::DBM.

◆ RebuildAdvanced()

Status tkrzw::SkipDBM::RebuildAdvanced	(	const TuningParameters &	tuning_params = `TuningParameters()`,
		bool	skip_broken_records = `false`,
		bool	sync_hard = `false`
	)

Rebuilds the entire database, in an advanced way.

Parameters

tuning_params	A structure for tuning parameters. The default value of each parameter means that the current setting is succeeded or calculated implicitly.
skip_broken_records	If true, the operation continues even if there are broken records which can be skipped. This is not used currently.
sync_hard	True to do physical synchronization with the hardware before finishing the rebuilt file.

Returns: The result status.

Precondition: The database is opened as writable.

Rebuilding a database is useful to optimize the size of the file.

◆ ShouldBeRebuilt()

Status tkrzw::SkipDBM::ShouldBeRebuilt ( bool * tobe )

overridevirtual

Checks whether the database should be rebuilt.

Parameters

tobe	The pointer to a boolean object to contain the result decision.

Returns: The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ Synchronize()

Status tkrzw::SkipDBM::Synchronize	(	bool	hard,
		FileProcessor *	proc = `nullptr`
	)

overridevirtual

Synchronizes the content of the database to the file system.

Parameters

hard	True to do physical synchronization with the hardware or false to do only logical synchronization with the file system.
proc	The pointer to the file processor object, whose Process method is called while the content of the file is synchronized. If it is nullptr, it is ignored.

Returns: The result status.

Precondition: The database is opened as writable.

All inserted records are written in the database file and they become visible. This operation rebuilds the entire database by merging the existing records and inserted records. No reducer is applied to records so that all records with duplicated keys are kept intact.

Implements tkrzw::DBM.

◆ SynchronizeAdvanced()

Status tkrzw::SkipDBM::SynchronizeAdvanced	(	bool	hard,
		FileProcessor *	proc = `nullptr`,
		ReducerType	reducer = `nullptr`
	)

Synchronizes the content of the database to the file system.

Parameters

hard	True to do physical synchronization with the hardware or false to do only logical synchronization with the file system.
proc	The pointer to the file processor object, whose Process method is called while the content of the file is synchronized. If it is nullptr, it is ignored.

Returns: The result status.

Parameters

reducer A reducer applied before stroing records. If it is nullptr, no reducer is applied and all records are kept intact.

Returns: The result status.

Precondition: The database is opened as writable.

All inserted records are written in the database file and they become visible. This operation rebuilds the entire database by merging the existing records and inserted records. Records of the same key given to the reducer are ordered in a way that the old value comes earlier than the new value. Thus, if you want to keep the old value, ReduceToFirst should be set. If you want to replace the old value with the new value, ReduceToLast should be set.

◆ Inspect()

std::vector<std::pair<std::string, std::string> > tkrzw::SkipDBM::Inspect ( )

overridevirtual

Inspects the database.

Returns: A vector of pairs of a property name and its value.

Implements tkrzw::DBM.

◆ IsOpen()

bool tkrzw::SkipDBM::IsOpen ( ) const

overridevirtual

Checks whether the database is open.

Returns: True if the database is open, or false if not.

Implements tkrzw::DBM.

◆ IsWritable()

bool tkrzw::SkipDBM::IsWritable ( ) const

overridevirtual

Checks whether the database is writable.

Returns: True if the database is writable, or false if not.

Implements tkrzw::DBM.

◆ IsHealthy()

bool tkrzw::SkipDBM::IsHealthy ( ) const

overridevirtual

Checks whether the database condition is healthy.

Returns: True if the database condition is healthy, or false if not.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ IsAutoRestored()

bool tkrzw::SkipDBM::IsAutoRestored ( ) const

Checks whether the database has been restored automatically.

Returns: True if the database condition has been restored by the last Open method.

Precondition: The database is opened.

◆ IsOrdered()

bool tkrzw::SkipDBM::IsOrdered ( ) const

overridevirtual

Checks whether ordered operations are supported.

Returns: Always true. Ordered operations are supported.

Implements tkrzw::DBM.

◆ MakeIterator()

std::unique_ptr<DBM::Iterator> tkrzw::SkipDBM::MakeIterator ( )

overridevirtual

Makes an iterator for each record.

Returns: The iterator for each record.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ MakeDBM()

std::unique_ptr<DBM> tkrzw::SkipDBM::MakeDBM ( ) const

overridevirtual

Makes a new DBM object of the same concrete class.

Returns: The new DBM object.

Implements tkrzw::DBM.

◆ GetUpdateLogger()

UpdateLogger* tkrzw::SkipDBM::GetUpdateLogger ( ) const

overridevirtual

Gets the logger to write all update operations.

Returns: The update logger if it has been set or nullptr if it hasn't.

Implements tkrzw::DBM.

◆ SetUpdateLogger()

void tkrzw::SkipDBM::SetUpdateLogger ( UpdateLogger * update_logger )

overridevirtual

Sets the logger to write all update operations.

Parameters

update_logger The pointer to the update logger object. Ownership is not taken. If it is nullptr, no logger is used.

Implements tkrzw::DBM.

◆ GetInternalFile()

File* tkrzw::SkipDBM::GetInternalFile ( ) const

Gets the pointer to the internal file object.

Returns: The pointer to the internal file object.

Accessing the internal file viorates encapsulation policy. This should be used only for testing and debugging.

◆ GetEffectiveDataSize()

int64_t tkrzw::SkipDBM::GetEffectiveDataSize ( )

Gets the effective data size.

Returns: The effective data size, or -1 on failure.

Precondition: The database is opened.

The effective data size means the total size of the keys and the values.

◆ GetDatabaseType()

int32_t tkrzw::SkipDBM::GetDatabaseType ( )

Gets the database type.

Returns: The database type, or -1 on failure.

Precondition: The database is opened.

◆ SetDatabaseType()

Status tkrzw::SkipDBM::SetDatabaseType ( uint32_t db_type )

Sets the database type.

Parameters

db_type The database type.

Returns: The result status.

Precondition: The database is opened as writable.

This data is just for applications and not used by the database implementation.

◆ GetOpaqueMetadata()

std::string tkrzw::SkipDBM::GetOpaqueMetadata ( )

Gets the opaque metadata.

Returns: The opaque metadata, or an empty string on failure.

Precondition: The database is opened.

◆ SetOpaqueMetadata()

Status tkrzw::SkipDBM::SetOpaqueMetadata ( const std::string & opaque )

Sets the opaque metadata.

Parameters

opaque The opaque metadata, of which leading 64 bytes are stored in the file.

Returns: The result status.

Precondition: The database is opened as writable.

This data is just for applications and not used by the database implementation.

◆ Revert()

Status tkrzw::SkipDBM::Revert ( )

Reverts all updates.

Precondition: The database is opened as writable and not finished.

All inserted records are discarded and the contents are returned to the state when the database was synchronized at the last time.

◆ IsUpdated()

bool tkrzw::SkipDBM::IsUpdated ( )

Checks whether the database has been updated after being opened.

Returns: True if the database has been updated after being opened.

Precondition: The database is opened.

◆ MergeSkipDatabase()

Status tkrzw::SkipDBM::MergeSkipDatabase ( const std::string & src_path )

Merges the contents of another skip database file.

Parameters

src_path A path to the source database file.

Returns: The result status.

Precondition: The database is opened as writable.

Merged records are shown after the database is synchronized. Among records of the same key, synchronized existing records come first, added records come second, and unsynchronized existing records come last.

◆ ValidateRecords()

Status tkrzw::SkipDBM::ValidateRecords ( )

Validates records.

Returns: The result status.

◆ ReduceRemove()

static std::vector<std::string> tkrzw::SkipDBM::ReduceRemove	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by removing REMOVING_VALUE and past values.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing surviving values.

◆ ReduceToFirst()

static std::vector<std::string> tkrzw::SkipDBM::ReduceToFirst	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by keeping the first value only.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing the first value.

◆ ReduceToSecond()

static std::vector<std::string> tkrzw::SkipDBM::ReduceToSecond	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by keeping the second or first value only.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing the first value.

◆ ReduceToLast()

static std::vector<std::string> tkrzw::SkipDBM::ReduceToLast	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by keeping the last value only.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing the last value.

◆ ReduceConcat()

static std::vector<std::string> tkrzw::SkipDBM::ReduceConcat	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by concatenating all values.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vectro containing the concatenated values.

◆ ReduceConcatWithNull()

static std::vector<std::string> tkrzw::SkipDBM::ReduceConcatWithNull	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by concatenating all values with null code.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vectro containing the concatenated values.

◆ ReduceConcatWithTab()

static std::vector<std::string> tkrzw::SkipDBM::ReduceConcatWithTab	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by concatenating all values with tab.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vectro containing the concatenated values.

◆ ReduceConcatWithLine()

static std::vector<std::string> tkrzw::SkipDBM::ReduceConcatWithLine	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by concatenating all values with linefeed.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vectro containing the concatenated values.

◆ ReduceToTotal()

static std::vector<std::string> tkrzw::SkipDBM::ReduceToTotal	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by totaling numeric expressions.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing the total numeric expression.

◆ ReduceToTotalBigEndian()

static std::vector<std::string> tkrzw::SkipDBM::ReduceToTotalBigEndian	(	const std::string &	key,
		const std::vector< std::string > &	values
	)

static

Reduces the values of records of the same key by totaling big-endian binary expressions.

Parameters

key	The common key of the records.
values	The values of the records of the same key.

Returns: A vector containing the total big-endian binary expression.

◆ ReadMetadata()

static Status tkrzw::SkipDBM::ReadMetadata	(	File *	file,
		int32_t *	cyclic_magic,
		int32_t *	pkg_major_version,
		int32_t *	pkg_minor_version,
		int32_t *	offset_width,
		int32_t *	step_unit,
		int32_t *	max_level,
		int32_t *	closure_flags,
		int64_t *	num_records,
		int64_t *	eff_data_size,
		int64_t *	file_size,
		int64_t *	mod_time,
		int32_t *	db_type,
		std::string *	opaque
	)

static

Reads metadata from a database file.

Parameters

file	A file object having opened the database file.
cyclic_magic	The pointer to a variable to store the cyclic magic data.
pkg_major_version	The pointer to a variable to store the package major version.
pkg_minor_version	The pointer to a variable to store the package minor version.
offset_width	The pointer to a variable to store the offset width.
step_unit	The pointer to a variable to store the step unit.
max_level	The pointer to a variable to store the max level.
closure_flags	The pointer to a variable to store the closure flags.
num_records	The pointer to a variable to store the number of records.
eff_data_size	The pointer to a variable to store the effective data size.
file_size	The pointer to a variable to store the file size.
mod_time	The pointer to a variable to store the last modified time.
db_type	The pointer to a variable to store the database type.
opaque	The pointer to a variable to store the opaque data.

Returns: The result status.

If the leading magic data is inconsistent, it returns failure. If the cyclic magic data is inconsistent, it returns success and -1 is assigned to cyclic_magic.

◆ RestoreDatabase()

static Status tkrzw::SkipDBM::RestoreDatabase	(	const std::string &	old_file_path,
		const std::string &	new_file_path
	)

static

Restores a broken database as a new healthy database.

Parameters

old_file_path	The path of the broken database.
new_file_path	The path of the new database to be created.

Returns: The result status.

Member Data Documentation

◆ DEFAULT_OFFSET_WIDTH

constexpr int32_t tkrzw::SkipDBM::DEFAULT_OFFSET_WIDTH = 4

staticconstexpr

The default value of the offset width.

◆ DEFAULT_STEP_UNIT

constexpr int32_t tkrzw::SkipDBM::DEFAULT_STEP_UNIT = 4

staticconstexpr

The default value of the step unit.

◆ DEFAULT_MAX_LEVEL

constexpr int32_t tkrzw::SkipDBM::DEFAULT_MAX_LEVEL = 14

staticconstexpr

The default value of the maximum level.

◆ DEFAULT_SORT_MEM_SIZE

constexpr int64_t tkrzw::SkipDBM::DEFAULT_SORT_MEM_SIZE = 256LL << 20

staticconstexpr

The default value of the memory size used for sorting.

◆ DEFAULT_MAX_CACHED_RECORDS

constexpr int32_t tkrzw::SkipDBM::DEFAULT_MAX_CACHED_RECORDS = 65536

staticconstexpr

The default value of the maximum cached records.

◆ OPAQUE_METADATA_SIZE

constexpr int32_t tkrzw::SkipDBM::OPAQUE_METADATA_SIZE = 64

staticconstexpr

The size of the opaque metadata.

◆ REMOVING_VALUE

const std::string tkrzw::SkipDBM::REMOVING_VALUE

static

The special removing value.

Classes

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ ReducerType

Member Enumeration Documentation

◆ RestoreMode

Constructor & Destructor Documentation

◆ SkipDBM() [1/3]

◆ SkipDBM() [2/3]

◆ ~SkipDBM()

◆ SkipDBM() [3/3]

Member Function Documentation

◆ Open()

◆ OpenAdvanced()

◆ Close()

◆ Process()

◆ Set()

◆ Remove()

◆ GetByIndex()

◆ ProcessMulti()

◆ ProcessFirst()

◆ ProcessEach()

◆ Count()

◆ GetFileSize()

◆ GetFilePath()

◆ GetTimestamp()

◆ Clear()

◆ Rebuild()

◆ RebuildAdvanced()

◆ ShouldBeRebuilt()

◆ Synchronize()

◆ SynchronizeAdvanced()

◆ Inspect()

◆ IsOpen()

◆ IsWritable()

◆ IsHealthy()

◆ IsAutoRestored()

◆ IsOrdered()

◆ MakeIterator()

◆ MakeDBM()

◆ GetUpdateLogger()

◆ SetUpdateLogger()

◆ GetInternalFile()

◆ GetEffectiveDataSize()

◆ GetDatabaseType()

◆ SetDatabaseType()

◆ GetOpaqueMetadata()

◆ SetOpaqueMetadata()

◆ Revert()

◆ IsUpdated()

◆ MergeSkipDatabase()

◆ ValidateRecords()

◆ ReduceRemove()

◆ ReduceToFirst()

◆ ReduceToSecond()

◆ ReduceToLast()

◆ ReduceConcat()

◆ ReduceConcatWithNull()

◆ ReduceConcatWithTab()

◆ ReduceConcatWithLine()

◆ ReduceToTotal()

◆ ReduceToTotalBigEndian()

◆ ReadMetadata()

◆ RestoreDatabase()

Member Data Documentation

◆ DEFAULT_OFFSET_WIDTH

◆ DEFAULT_STEP_UNIT

◆ DEFAULT_MAX_LEVEL

◆ DEFAULT_SORT_MEM_SIZE

◆ DEFAULT_MAX_CACHED_RECORDS

◆ OPAQUE_METADATA_SIZE

◆ REMOVING_VALUE