Tkrzw
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tkrzw::TreeDBM Class Referencefinal

File database manager implementation based on B+ tree. More...

#include <tkrzw_dbm_tree.h>

Classes

class  Iterator
 Iterator for each record. More...
 
struct  TuningParameters
 Tuning parameters for the database. More...
 

Public Types

enum  PageUpdateMode : int32_t { PAGE_UPDATE_DEFAULT = 0 , PAGE_UPDATE_NONE = 1 , PAGE_UPDATE_WRITE = 2 }
 Enumeration for page update modes. 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

 TreeDBM ()
 Default constructor. More...
 
 TreeDBM (std::unique_ptr< File > file)
 Constructor with a file object. More...
 
 ~TreeDBM ()
 Destructor. More...
 
 TreeDBM (const TreeDBM &rhs)=delete
 Copy and assignment are disabled. More...
 
TreeDBMoperator= (const TreeDBM &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 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 GetTimestamp (double *timestamp) override
 Gets the timestamp in seconds of the last modified time. More...
 
Status GetFilePath (std::string *path) override
 Gets the path of the database file. 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...
 
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::IteratorMakeIterator () override
 Makes an iterator for each record. More...
 
std::unique_ptr< DBMMakeDBM () const override
 Makes a new DBM object of the same concrete class. More...
 
UpdateLoggerGetUpdateLogger () 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...
 
FileGetInternalFile () 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...
 
KeyComparator GetKeyComparator () const
 Gets the comparator of record keys. More...
 
Status ValidateHashBuckets ()
 Validate all buckets in the hash table. More...
 
Status ValidateRecords (int64_t record_base, int64_t end_offset)
 Validates records in a region. 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 Set (std::string_view key, std::string_view value, bool overwrite=true, std::string *old_value=nullptr)
 Sets a record of a key and a value. 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 Remove (std::string_view key, std::string *old_value=nullptr)
 Removes a record of a key. 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 Status ParseMetadata (std::string_view opaque, int64_t *num_records, int64_t *eff_data_size, int64_t *root_id, int64_t *first_id, int64_t *last_id, int64_t *num_leaf_nodes, int64_t *num_inner_nodes, int32_t *max_page_size, int32_t *max_branches, int32_t *tree_level, int32_t *key_comp_type, std::string *mini_opaque)
 Parses metadata on an opaque data sequence. More...
 
static Status RestoreDatabase (const std::string &old_file_path, const std::string &new_file_path, int64_t end_offset, std::string_view cipher_key="")
 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_ALIGN_POW = 10
 The default value of the alignment power. More...
 
static constexpr int64_t DEFAULT_NUM_BUCKETS = 131101
 The default value of the number of buckets. More...
 
static constexpr int32_t DEFAULT_FBP_CAPACITY = 2048
 The default value of the capacity of the free block pool. More...
 
static constexpr int32_t DEFAULT_MAX_PAGE_SIZE = 8130
 The default value of the max page size. More...
 
static constexpr int32_t DEFAULT_MAX_BRANCHES = 256
 The default value of the max branches. More...
 
static constexpr int32_t DEFAULT_MAX_CACHED_PAGES = 10000
 The default value of the maximum number of cached pages. More...
 
static constexpr int32_t OPAQUE_METADATA_SIZE = 10
 The size of the opaque metadata. 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 B+ tree.

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 Enumeration Documentation

◆ PageUpdateMode

Enumeration for page update modes.

Enumerator
PAGE_UPDATE_DEFAULT 

The default behavior: no operation or to succeed the current mode.

PAGE_UPDATE_NONE 

To do no operation.

PAGE_UPDATE_WRITE 

To write immediately.

Constructor & Destructor Documentation

◆ TreeDBM() [1/3]

tkrzw::TreeDBM::TreeDBM ( )

Default constructor.

MemoryMapParallelFile is used to handle the data.

◆ TreeDBM() [2/3]

tkrzw::TreeDBM::TreeDBM ( std::unique_ptr< File file)
explicit

Constructor with a file object.

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

◆ ~TreeDBM()

tkrzw::TreeDBM::~TreeDBM ( )

Destructor.

◆ TreeDBM() [3/3]

tkrzw::TreeDBM::TreeDBM ( const TreeDBM rhs)
explicitdelete

Copy and assignment are disabled.

Member Function Documentation

◆ Open()

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

Opens a database file.

Parameters
pathA path of the file.
writableIf true, the file is writable. If false, it is read-only.
optionsBit-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::TreeDBM::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
pathA path of the file.
writableIf true, the file is writable. If false, it is read-only.
optionsBit-sum options for opening the file.
tuning_paramsA structure for tuning parameters.
Returns
The result status.

Precondition: The database is not opened.

◆ Close()

Status tkrzw::TreeDBM::Close ( )
overridevirtual

Closes the database file.

Returns
The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ Process()

Status tkrzw::TreeDBM::Process ( std::string_view  key,
RecordProcessor proc,
bool  writable 
)
overridevirtual

Processes a record with a processor.

Parameters
keyThe key of the record.
procThe pointer to the processor object.
writableTrue 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.

Implements tkrzw::DBM.

◆ ProcessMulti()

Status tkrzw::TreeDBM::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_pairsPairs of the keys and their processor objects.
writableTrue 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::TreeDBM::ProcessFirst ( RecordProcessor proc,
bool  writable 
)
overridevirtual

Processes the first record with a processor.

Parameters
procThe pointer to the processor object.
writableTrue 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::TreeDBM::ProcessEach ( RecordProcessor proc,
bool  writable 
)
overridevirtual

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

Parameters
procThe pointer to the processor object.
writableTrue 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::TreeDBM::Count ( int64_t *  count)
overridevirtual

Gets the number of records.

Parameters
countThe 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::TreeDBM::GetFileSize ( int64_t *  size)
overridevirtual

Gets the current file size of the database.

Parameters
sizeThe pointer to an integer object to contain the result size.
Returns
The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ GetTimestamp()

Status tkrzw::TreeDBM::GetTimestamp ( double *  timestamp)
overridevirtual

Gets the timestamp in seconds of the last modified time.

Parameters
timestampThe 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.

◆ GetFilePath()

Status tkrzw::TreeDBM::GetFilePath ( std::string *  path)
overridevirtual

Gets the path of the database file.

Parameters
pathThe pointer to a string object to contain the result path.
Returns
The result status.

Precondition: The database is opened.

Implements tkrzw::DBM.

◆ Clear()

Status tkrzw::TreeDBM::Clear ( )
overridevirtual

Removes all records.

Returns
The result status.

Precondition: The database is opened as writable.

Implements tkrzw::DBM.

◆ Rebuild()

Status tkrzw::TreeDBM::Rebuild ( )
overridevirtual

Rebuilds the entire database.

Returns
The result status.

Precondition: The database is opened as writable.

Rebuilding a database is useful to reduce the size of the file by solving fragmentation. All tuning parameters are succeeded or calculated implicitly.

Implements tkrzw::DBM.

◆ RebuildAdvanced()

Status tkrzw::TreeDBM::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_paramsA structure for tuning parameters. The default value of each parameter means that the current setting is succeeded or calculated implicitly.
skip_broken_recordsIf true, the operation continues even if there are broken records which can be skipped.
sync_hardTrue 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 reduce the size of the file by solving fragmentation. Tuning parameters for the underlying hash database are reflected on the rebuilt file on the spot. Tuning parameters for B+ tree are reflected gradually while updating the database later. The comparator of record keys cannot be changed.

◆ ShouldBeRebuilt()

Status tkrzw::TreeDBM::ShouldBeRebuilt ( bool *  tobe)
overridevirtual

Checks whether the database should be rebuilt.

Parameters
tobeThe 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::TreeDBM::Synchronize ( bool  hard,
FileProcessor proc = nullptr 
)
overridevirtual

Synchronizes the content of the database to the file system.

Parameters
hardTrue to do physical synchronization with the hardware or false to do only logical synchronization with the file system.
procThe 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.

Implements tkrzw::DBM.

◆ Inspect()

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

Inspects the database.

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

Implements tkrzw::DBM.

◆ IsOpen()

bool tkrzw::TreeDBM::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::TreeDBM::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::TreeDBM::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::TreeDBM::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::TreeDBM::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::TreeDBM::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::TreeDBM::MakeDBM ( ) const
overridevirtual

Makes a new DBM object of the same concrete class.

Returns
The new DBM object.

Implements tkrzw::DBM.

◆ GetUpdateLogger()

UpdateLogger* tkrzw::TreeDBM::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::TreeDBM::SetUpdateLogger ( UpdateLogger update_logger)
overridevirtual

Sets the logger to write all update operations.

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

Precondition: The database is not opened.

Implements tkrzw::DBM.

◆ GetInternalFile()

File* tkrzw::TreeDBM::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::TreeDBM::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. This figure might deviate if auto restore happens.

◆ GetDatabaseType()

int32_t tkrzw::TreeDBM::GetDatabaseType ( )

Gets the database type.

Returns
The database type, or -1 on failure.

Precondition: The database is opened.

◆ SetDatabaseType()

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

Sets the database type.

Parameters
db_typeThe 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::TreeDBM::GetOpaqueMetadata ( )

Gets the opaque metadata.

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

Precondition: The database is opened.

◆ SetOpaqueMetadata()

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

Sets the opaque metadata.

Parameters
opaqueThe opaque metadata, of which leading 16 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.

◆ GetKeyComparator()

KeyComparator tkrzw::TreeDBM::GetKeyComparator ( ) const

Gets the comparator of record keys.

Returns
The key comparator function, or nullptr on failure.

Precondition: The database is opened.

◆ ValidateHashBuckets()

Status tkrzw::TreeDBM::ValidateHashBuckets ( )

Validate all buckets in the hash table.

Returns
The result status.

◆ ValidateRecords()

Status tkrzw::TreeDBM::ValidateRecords ( int64_t  record_base,
int64_t  end_offset 
)

Validates records in a region.

Parameters
record_baseThe beginning offset of records to check. Negative means the beginning of the record section.
end_offsetThe exclusive end offset of records to check. Negative means unlimited. 0 means the size when the database is synched or closed properly.
Returns
The result status.

◆ ParseMetadata()

static Status tkrzw::TreeDBM::ParseMetadata ( std::string_view  opaque,
int64_t *  num_records,
int64_t *  eff_data_size,
int64_t *  root_id,
int64_t *  first_id,
int64_t *  last_id,
int64_t *  num_leaf_nodes,
int64_t *  num_inner_nodes,
int32_t *  max_page_size,
int32_t *  max_branches,
int32_t *  tree_level,
int32_t *  key_comp_type,
std::string *  mini_opaque 
)
static

Parses metadata on an opaque data sequence.

Parameters
opaqueThe opaque data from the underlying database.
num_recordsThe pointer to a variable to store the number of buckets.
eff_data_sizeThe pointer to a variable to store the effective data size.
root_idThe pointer to a variable to store the ID of the root node.
first_idThe pointer to a variable to store the ID of the first node.
last_idThe pointer to a variable to store the ID of the last node.
num_leaf_nodesThe pointer to a variable to store the number of leaf nodes.
num_inner_nodesThe pointer to a variable to store the number of inner nodes.
max_page_sizeThe pointer to a variable to store the max page size.
max_branchesThe pointer to a variable to store the max branches.
tree_levelThe pointer to a variable to store the tree level.
key_comp_typeThe pointer to a variable to store the key comparator type.
mini_opaqueThe pointer to a variable to store the mini opaque data.
Returns
The result status.

◆ RestoreDatabase()

static Status tkrzw::TreeDBM::RestoreDatabase ( const std::string &  old_file_path,
const std::string &  new_file_path,
int64_t  end_offset,
std::string_view  cipher_key = "" 
)
static

Restores a broken database as a new healthy database.

Parameters
old_file_pathThe path of the broken database.
new_file_pathThe path of the new database to be created.
end_offsetThe exclusive end offset of records to read. Negative means unlimited. 0 means the size when the database is synched or closed properly. INT64MIN and INT64MAX mean to omit restore of the underlying hash database. Then, INT64MIN is unlimited and INT64MAX means synched restoration.
cipher_keyThe encryption key for cipher compressors.
Returns
The result status.

Member Data Documentation

◆ DEFAULT_OFFSET_WIDTH

constexpr int32_t tkrzw::TreeDBM::DEFAULT_OFFSET_WIDTH = 4
staticconstexpr

The default value of the offset width.

◆ DEFAULT_ALIGN_POW

constexpr int32_t tkrzw::TreeDBM::DEFAULT_ALIGN_POW = 10
staticconstexpr

The default value of the alignment power.

◆ DEFAULT_NUM_BUCKETS

constexpr int64_t tkrzw::TreeDBM::DEFAULT_NUM_BUCKETS = 131101
staticconstexpr

The default value of the number of buckets.

◆ DEFAULT_FBP_CAPACITY

constexpr int32_t tkrzw::TreeDBM::DEFAULT_FBP_CAPACITY = 2048
staticconstexpr

The default value of the capacity of the free block pool.

◆ DEFAULT_MAX_PAGE_SIZE

constexpr int32_t tkrzw::TreeDBM::DEFAULT_MAX_PAGE_SIZE = 8130
staticconstexpr

The default value of the max page size.

◆ DEFAULT_MAX_BRANCHES

constexpr int32_t tkrzw::TreeDBM::DEFAULT_MAX_BRANCHES = 256
staticconstexpr

The default value of the max branches.

◆ DEFAULT_MAX_CACHED_PAGES

constexpr int32_t tkrzw::TreeDBM::DEFAULT_MAX_CACHED_PAGES = 10000
staticconstexpr

The default value of the maximum number of cached pages.

◆ OPAQUE_METADATA_SIZE

constexpr int32_t tkrzw::TreeDBM::OPAQUE_METADATA_SIZE = 10
staticconstexpr

The size of the opaque metadata.