tkrzw::DBMUpdateLoggerMQ Class Reference

DBM update logger with a message queue. More...

#include <tkrzw_dbm_ulog.h>

Classes
struct	UpdateLog
	Common structure of an update log. More...

Public Types
enum	OpType : int32_t { OP_VOID = 0 , OP_SET = 1 , OP_REMOVE = 2 , OP_CLEAR = 3 }
	Enumeration for operation types. More...

Public Member Functions
	DBMUpdateLoggerMQ (MessageQueue *mq, int32_t server_id=0, int32_t dbm_index=0, int64_t fixed_timestamp=-1)
	Constructor. More...
Status	WriteSet (std::string_view key, std::string_view value) override
	Writes a log for modifying an existing record or adding a new record. More...
Status	WriteRemove (std::string_view key) override
	Writes a log for removing an existing record. More...
Status	WriteClear () override
	Writes a log for removing all records. More...
Status	Synchronize (bool hard) override
	Synchronizes the metadata and content to the file system. More...
Public Member Functions inherited from tkrzw::DBM::UpdateLogger
virtual	~UpdateLogger ()=default
	Destructor. More...

Static Public Member Functions
static void	OverwriteThreadServerID (int32_t server_id)
	Overwrites the server ID of the current thread. More...
static Status	ParseUpdateLog (std::string_view message, UpdateLog *op)
	Parses an update log message. More...
static Status	ApplyUpdateLog (DBM *dbm, std::string_view message, int32_t server_id=INT32MIN+1, int32_t dbm_index=INT32MIN+1)
	Applys the operation in an update log to a database. More...
static Status	ApplyUpdateLogFromFiles (DBM *dbm, const std::string &prefix, double min_timestamp=0, int32_t server_id=INT32MIN+1, int32_t dbm_index=INT32MIN+1)
	Applys the operations in the message queue files. More...

Detailed Description

DBM update logger with a message queue.

Member Enumeration Documentation

OpType

enum tkrzw::DBMUpdateLoggerMQ::OpType : int32_t

Enumeration for operation types.

Enumerator
OP_VOID	Invalid operation.
OP_SET	To modify or add a record.
OP_REMOVE	To remove a record.
OP_CLEAR	To remove all records.

Constructor & Destructor Documentation

DBMUpdateLoggerMQ()

tkrzw::DBMUpdateLoggerMQ::DBMUpdateLoggerMQ ( MessageQueue *  mq, int32_t  server_id = 0, int32_t  dbm_index = 0, int64_t  fixed_timestamp = -1  )

explicit

Constructor.

Parameters

mq	The message queue object to store update logs. The ownership is not taken.
server_id	The server ID of the process.
dbm_index	The index of the DBM on the server.
fixed_timestamp	If not negative, the timestamp is fixed to the value.

Member Function Documentation

WriteSet()

Status tkrzw::DBMUpdateLoggerMQ::WriteSet ( std::string_view  key, std::string_view  value  )

overridevirtual

Writes a log for modifying an existing record or adding a new record.

Parameters

key	The key of the record.
value	The new value of the record.

Returns

The result status.

Implements tkrzw::DBM::UpdateLogger.

WriteRemove()

Status tkrzw::DBMUpdateLoggerMQ::WriteRemove ( std::string_view  key )

overridevirtual

Writes a log for removing an existing record.

Parameters

key	The key of the record.

Returns

The result status.

Implements tkrzw::DBM::UpdateLogger.

WriteClear()

Status tkrzw::DBMUpdateLoggerMQ::WriteClear ( )

overridevirtual

Writes a log for removing all records.

Returns

The result status.

Implements tkrzw::DBM::UpdateLogger.

Synchronize()

Status tkrzw::DBMUpdateLoggerMQ::Synchronize ( bool  hard )

overridevirtual

Synchronizes the metadata and content 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.

Returns

The result status.

Reimplemented from tkrzw::DBM::UpdateLogger.

OverwriteThreadServerID()

static void tkrzw::DBMUpdateLoggerMQ::OverwriteThreadServerID ( int32_t  server_id )

static

Overwrites the server ID of the current thread.

Parameters

server_id

The server ID of the process. If it is negative, the thread local setting is undone. If it is INT32MIN, logging of the current thread is disable.

This affects logging of only the current thread regardless of the logger instance.

ParseUpdateLog()

static Status tkrzw::DBMUpdateLoggerMQ::ParseUpdateLog ( std::string_view  message, UpdateLog *  op  )

static

Parses an update log message.

Parameters

message	The update log message.
op	The pointer to the update log object to store the result. The life duration of the key and the value fields is the same as the given message.

Returns

The result status.

ApplyUpdateLog()

static Status tkrzw::DBMUpdateLoggerMQ::ApplyUpdateLog ( DBM *  dbm, std::string_view  message, int32_t  server_id = INT32MIN+1, int32_t  dbm_index = INT32MIN+1  )

static

Applys the operation in an update log to a database.

Parameters

dbm	The DBM object of the database.
message	The update log message.
server_id	The server ID to focus on. A negative applies a filter which ignores the message if the server ID mathces the absolute value. Zero or a positive applies a filter which adopts the message if the server ID matches the value.
dbm_index	The DBM index to focus on. A negative applies a filter which ignores the message if the DBM index mathces the absolute value. Zero or a positive applies a filter which adopts the message if the DBM index matches the value.

Returns

The result status. If the log is ignored due to the filter, INFEASIBLE_ERROR is returned.

ApplyUpdateLogFromFiles()

static Status tkrzw::DBMUpdateLoggerMQ::ApplyUpdateLogFromFiles ( DBM *  dbm, const std::string &  prefix, double  min_timestamp = 0, int32_t  server_id = INT32MIN+1, int32_t  dbm_index = INT32MIN+1  )

static

Applys the operations in the message queue files.

Parameters

dbm	The DBM object of the database.
prefix	The prefix for the message queue file names.
min_timestamp	The minimum timestamp in milliseconds of messages to read.
server_id	The server ID to focus on. A negative applies a filter which ignores the message if the server ID mathces the absolute value. Zero or a positive applies a filter which adopts the message if the server ID matches the value.
dbm_index	The DBM index to focus on. A negative applies a filter which ignores the message if the DBM index mathces the absolute value. Zero or a positive applies a filter which adopts the message if the DBM index matches the value.

Returns

The result status.