2.3.9 The LogfileGroup Class

This section provides information about the LogfileGroup class, which models an NDB Cluster Disk Data log file group.

• LogFileGroup Class Overview

• LogfileGroup Constructor

• LogfileGroup::getAutoGrowSpecification()

• LogfileGroup::getName()

• LogfileGroup::getObjectId()

• LogfileGroup::getObjectStatus()

• LogfileGroup::getObjectVersion()

• LogfileGroup::getUndoBufferSize()

• LogfileGroup::getUndoFreeWords()

• LogfileGroup::setAutoGrowSpecification()

• LogfileGroup::setName()

• LogfileGroup::setUndoBufferSize()

LogFileGroup Class Overview

Parent class

NdbDictionary

Child classes

None

Description

This class represents an NDB Cluster Disk Data log file group, which is used for storing Disk Data undo files. For general information about log file groups and undo files, see NDB Cluster Disk Data Tables, in the MySQL Manual.

Only unindexed column data can be stored on disk. Indexes and indexes columns are always stored in memory.

Methods

The following table lists the public methods of this class and the purpose or use of each method:

Table 2.25 LogfileGroup class methods and descriptions

Name	Description
LogfileGroup()	Class constructor
~LogfileGroup()	Virtual destructor
getAutoGrowSpecification()	Gets the log file group's AutoGrowSpecification values
getName()	Retrieves the log file group's name
getObjectId()	Get the object ID of the log file group
getObjectStatus()	Gets the log file group's object status value
getObjectVersion()	Retrieves the log file group's object version
getUndoBufferSize()	Gets the size of the log file group's undo buffer
getUndoFreeWords()	Retrieves the amount of free space in the undo buffer
setAutoGrowSpecification()	Sets AutoGrowSpecification values for the log file group
setName()	Sets the name of the log file group
setUndoBufferSize()	Sets the size of the log file group's undo buffer.

Types

While the LogfileGroup class does not itself define any public types, two of its methods make use of the AutoGrowSpecification data structure as a parameter or return value.

LogfileGroup Constructor

Description

The LogfileGroup class has two public constructors, one of which takes no arguments and creates a completely new instance. The other is a copy constructor.

The Dictionary class also supplies methods for creating and destroying LogfileGroup objects. See Section 2.3.3, “The Dictionary Class”.

Signatures

New instance:

LogfileGroup
    (
      void
    )

Copy constructor:

LogfileGroup
    (
      const LogfileGroup& logfileGroup
    )

Parameters

When creating a new instance, the constructor takes no parameters. When copying an existing instance, the constructor is passed a reference to the LogfileGroup instance to be copied.

Return value

A LogfileGroup object.

Destructor

virtual ~LogfileGroup
    (
      void
    )

LogfileGroup::getAutoGrowSpecification()

Description

This method retrieves the AutoGrowSpecification associated with the log file group.

Signature

const AutoGrowSpecification& getAutoGrowSpecification
    (
      void
    ) const

Parameters

None.

Return value

An AutoGrowSpecification data structure.

LogfileGroup::getName()

Description

This method gets the name of the log file group.

Signature

const char* getName
    (
      void
    ) const

Parameters

None.

Return value

The logfile group's name, a string (as a character pointer).

LogfileGroup::getObjectId()

Description

This method is used to retrieve the object ID of the log file group.

Signature

virtual int getObjectId
    (
      void
    ) const

Parameters

None.

Return value

The log file group's object ID (an integer value).

LogfileGroup::getObjectStatus()

Description

This method is used to obtain the object status of the LogfileGroup.

Signature

virtual Object::Status getObjectStatus
    (
      void
    ) const

Parameters

None.

Return value

The logfile group's Status—see Object::Status for possible values.

LogfileGroup::getObjectVersion()

Description

This method gets the log file group's object version (see NDB Schema Object Versions).

Signature

virtual int getObjectVersion
    (
      void
    ) const

Parameters

None.

Return value

The object version of the log file group, as an integer.

LogfileGroup::getUndoBufferSize()

Description

This method retrieves the size of the log file group's undo buffer.

Signature

Uint32 getUndoBufferSize
    (
      void
    ) const

Parameters

None.

Return value

The size of the undo buffer, in bytes.

LogfileGroup::getUndoFreeWords()

Description

This method retrieves the number of bytes unused in the log file group's undo buffer.

Signature

Uint64 getUndoFreeWords
    (
      void
    ) const

Parameters

None.

Return value

The number of bytes free, as a 64-bit integer.

LogfileGroup::setAutoGrowSpecification()

Description

This method sets the AutoGrowSpecification data for the log file group.

Signature

void setAutoGrowSpecification
    (
      const AutoGrowSpecification& autoGrowSpec
    )

Parameters

The data is passed as a single parameter, an AutoGrowSpecification data structure.

Return value

None.

LogfileGroup::setName()

Description

This method is used to set a name for the log file group.

Signature

void setName
    (
      const char* name
    )

Parameters

The name to be given to the logfile group (character pointer).

Return value

None.

LogfileGroup::setUndoBufferSize()

Description

This method can be used to set the size of the log file group's undo buffer.

Signature

void setUndoBufferSize
    (
      Uint32 size
    )

Parameters

The size in bytes for the undo buffer (using a 32-bit unsigned integer value).

Return value

None.