com.persistit

Class BackupTask

java.lang.Object

com.persistit.Task

com.persistit.BackupTask

All Implemented Interfaces:

Runnable

public class BackupTask
extends Task

Task to perform and/or control hot (concurrent) backup. Generally the process of copying large data files is best done by third party utility software. This class provides built-in ability to copy database files, but production configurations will likely use only the control mechanisms of this class and will run external programs to perform data compression and copying.

To perform a concurrent backup, Persistit needs to ensure that the state of copied volume files plus journal files is sufficient to ensure a consistent, fast recovery process. This is done by setting Persistit to appendOnly mode, which causes Persistit not to modify its Volume files and not to delete any journal files. A snapshot of the journal file and volume provides a reliable source for recovery.

This class provides a Task implementation that sets and resets the appendOnly flag, provides a list a files needing to be copied to form a complete backup, and as a convenience, a mechanism to compress and copy them.

Field Summary

Fields inherited from class com.persistit.Task

_culledMessageCount, _description, _expirationTime, _finishTime, _lastException, _maxMessageLogSize, _messageLog, _messageLogVerbosity, _messageWriter, _owner, _persistit, _startTime, _state, _stop, _suspend, _suspendedDuration, _taskId, _thread, DEFAULT_MAX_MESSAGE_LOG_SIZE, LOG_NORMAL, LOG_VERBOSE, STATE_DONE, STATE_ENDED, STATE_EXPIRED, STATE_FAILED, STATE_NAMES, STATE_NOT_STARTED, STATE_RUNNING, STATE_SUSPENDED

Constructor Summary

Constructors

Constructor and Description
BackupTask()

Method Summary

Modifier and Type	Method and Description
void	doRestore(String path) A convenience method for unit tests to unzip a backup created by doBackup().
List<String>	getFileList()
String	getStatus() Returns a short String message describing the current state of this Task.
protected void	postMessage(String message, int level) Posts a message (typically to denote progress, error or other interim information) to the message log.
protected void	runTask() Called by a newly created Thread to perform the task.

Methods inherited from class com.persistit.Task

appendMessage, cullMessages, endMessage, getMessageLogSize, getMessageLogVerbosity, getMessages, getMessageWriter, getRemainingTime, getStatusDetail, isImmediate, now, parseTreeList, poll, populateTaskStatus, resume, run, setMaximumTime, setMessageLogVerbosity, setMessageWriter, setPersistit, setup, start, stop, suspend

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BackupTask

public BackupTask()

Method Detail

runTask

protected void runTask()
                throws Exception

Description copied from class: Task

Called by a newly created Thread to perform the task.

Specified by:

runTask in class Task

Throws:

Exception

postMessage

protected void postMessage(String message,
                           int level)

Description copied from class: Task

Posts a message (typically to denote progress, error or other interim information) to the message log.

Overrides:

postMessage in class Task

Parameters:

message - The message

level - Indicates the verbosity level. The message is posted only if the level of the message is below the current verbosity threshhold set through Task.setMessageLogVerbosity(int).

doRestore

public void doRestore(String path)
               throws Exception

A convenience method for unit tests to unzip a backup created by doBackup(). In production it is expected a backup produced by doBackup() will be restored via an external unzip utility.

Throws:

Exception

getStatus

public String getStatus()

Description copied from class: Task

Returns a short String message describing the current state of this Task. It should convey a measurement of progress to the end-user.

Specified by:

getStatus in class Task

Returns:

A description of this Task's current state

getFileList

public List<String> getFileList()