org.apache.hadoop.mapred
Class FileOutputCommitter

java.lang.Object
  org.apache.hadoop.mapreduce.OutputCommitter
      org.apache.hadoop.mapred.OutputCommitter
          org.apache.hadoop.mapred.FileOutputCommitter

@InterfaceAudience.Public
@InterfaceStability.Stable
public class FileOutputCommitter
extends OutputCommitter

An OutputCommitter that commits files specified in job output directory i.e. ${mapreduce.output.fileoutputformat.outputdir}.

Field Summary

static org.apache.commons.logging.Log	LOG
static String	SUCCEEDED_FILE_NAME
static String	TEMP_DIR_NAME Temporary directory name

Constructor Summary

FileOutputCommitter()

Method Summary

void	abortJob(JobContext context, int runState) For aborting an unsuccessful job's output.
void	abortTask(TaskAttemptContext context) Discard the task output
void	cleanupJob(JobContext context) Deprecated.
void	commitJob(JobContext context) For committing job's output after successful job completion.
void	commitTask(TaskAttemptContext context) To promote the task's temporary output to final output location The task's output is moved to the job's output directory.
org.apache.hadoop.fs.Path	getWorkPath(TaskAttemptContext context, org.apache.hadoop.fs.Path outputPath)
boolean	isRecoverySupported() This method implements the new interface by calling the old method.
boolean	needsTaskCommit(TaskAttemptContext context) Check whether task needs a commit
void	recoverTask(TaskAttemptContext context) Recover the task output.
void	setupJob(JobContext context) For the framework to setup the job output during initialization
void	setupTask(TaskAttemptContext context) Sets up output for the task.

Methods inherited from class org.apache.hadoop.mapred.OutputCommitter

abortJob, abortTask, cleanupJob, commitJob, commitTask, needsTaskCommit, recoverTask, setupJob, setupTask

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

TEMP_DIR_NAME

public static final String TEMP_DIR_NAME

Temporary directory name

See Also:

Constant Field Values

SUCCEEDED_FILE_NAME

public static final String SUCCEEDED_FILE_NAME

See Also:

Constant Field Values

Constructor Detail

FileOutputCommitter

public FileOutputCommitter()

Method Detail

getWorkPath

public org.apache.hadoop.fs.Path getWorkPath(TaskAttemptContext context,
                                             org.apache.hadoop.fs.Path outputPath)
                                      throws IOException

Throws:

IOException

setupJob

public void setupJob(JobContext context)
              throws IOException

Description copied from class: OutputCommitter

For the framework to setup the job output during initialization

Specified by:

setupJob in class OutputCommitter

Parameters:

context - Context of the job whose output is being written.

Throws:

IOException - if temporary output could not be created

commitJob

public void commitJob(JobContext context)
               throws IOException

Description copied from class: OutputCommitter

For committing job's output after successful job completion. Note that this is invoked for jobs with final runstate as SUCCESSFUL.

Overrides:

commitJob in class OutputCommitter

Parameters:

context - Context of the job whose output is being written.

Throws:

IOException

cleanupJob

@Deprecated
public void cleanupJob(JobContext context)
                throws IOException

Deprecated.

Description copied from class: OutputCommitter

For cleaning up the job's output after job completion

Overrides:

cleanupJob in class OutputCommitter

Parameters:

context - Context of the job whose output is being written.

Throws:

IOException

abortJob

public void abortJob(JobContext context,
                     int runState)
              throws IOException

Description copied from class: OutputCommitter

For aborting an unsuccessful job's output. Note that this is invoked for jobs with final runstate as JobStatus.FAILED or JobStatus.KILLED

Overrides:

abortJob in class OutputCommitter

Parameters:

context - Context of the job whose output is being written.

runState - final runstate of the job

Throws:

IOException

setupTask

public void setupTask(TaskAttemptContext context)
               throws IOException

Description copied from class: OutputCommitter

Sets up output for the task.

Specified by:

setupTask in class OutputCommitter

Parameters:

context - Context of the task whose output is being written.

Throws:

IOException

commitTask

public void commitTask(TaskAttemptContext context)
                throws IOException

Description copied from class: OutputCommitter

To promote the task's temporary output to final output location The task's output is moved to the job's output directory.

Specified by:

commitTask in class OutputCommitter

Parameters:

context - Context of the task whose output is being written.

Throws:

IOException - if commit is not

abortTask

public void abortTask(TaskAttemptContext context)
               throws IOException

Description copied from class: OutputCommitter

Discard the task output

Specified by:

abortTask in class OutputCommitter

Throws:

IOException

needsTaskCommit

public boolean needsTaskCommit(TaskAttemptContext context)
                        throws IOException

Description copied from class: OutputCommitter

Check whether task needs a commit

Specified by:

needsTaskCommit in class OutputCommitter

Returns:

true/false

Throws:

IOException

isRecoverySupported

public boolean isRecoverySupported()

Description copied from class: OutputCommitter

This method implements the new interface by calling the old method. Note that the input types are different between the new and old apis and this is a bridge between the two.

Overrides:

isRecoverySupported in class OutputCommitter

Returns:

true if task output recovery is supported, false otherwise

See Also:

OutputCommitter.recoverTask(TaskAttemptContext)

recoverTask

public void recoverTask(TaskAttemptContext context)
                 throws IOException

Description copied from class: OutputCommitter

Recover the task output. The retry-count for the job will be passed via the MRConstants.APPLICATION_ATTEMPT_ID key in JobContext.getConfiguration() for the OutputCommitter. If an exception is thrown the task will be attempted again.

Overrides:

recoverTask in class OutputCommitter

Parameters:

context - Context of the task whose output is being recovered

Throws:

IOException