Package org.apache.hadoop.mapred.lib.db

Class DBOutputFormat<K extends DBWritable,V>

java.lang.Object

org.apache.hadoop.mapreduce.OutputFormat<K,V>

org.apache.hadoop.mapreduce.lib.db.DBOutputFormat<K,V>

org.apache.hadoop.mapred.lib.db.DBOutputFormat<K,V>

All Implemented Interfaces:

OutputFormat<K,V>

@Public
@Stable
public class DBOutputFormat<K extends DBWritable,V>
extends DBOutputFormat<K,V>
implements OutputFormat<K,V>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	org.apache.hadoop.mapred.lib.db.DBOutputFormat.DBRecordWriter	A RecordWriter that writes the reduce output to a SQL table

Field Summary

Fields inherited from class org.apache.hadoop.mapreduce.lib.db.DBOutputFormat

dbProductName

Constructor Summary

Constructors

Constructor	Description
DBOutputFormat()

Method Summary

Modifier and Type	Method	Description
void	checkOutputSpecs(FileSystem filesystem, JobConf job)	Check for validity of the output-specification for the job.
RecordWriter<K,V>	getRecordWriter(FileSystem filesystem, JobConf job, String name, Progressable progress)	Get the RecordWriter for the given job.
static void	setOutput(JobConf job, String tableName, int fieldCount)	Initializes the reduce-part of the job with the appropriate output settings
static void	setOutput(JobConf job, String tableName, String... fieldNames)	Initializes the reduce-part of the job with the appropriate output settings

Methods inherited from class org.apache.hadoop.mapreduce.lib.db.DBOutputFormat

checkOutputSpecs, constructQuery, getOutputCommitter, getRecordWriter, setOutput, setOutput

Methods inherited from class java.lang.Object

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

Constructor Details

DBOutputFormat

public DBOutputFormat()

Method Details

checkOutputSpecs

public void checkOutputSpecs(FileSystem filesystem,
 JobConf job)
                      throws IOException

Check for validity of the output-specification for the job.

This is to validate the output specification for the job when it is a job is submitted. Typically checks that it does not already exist, throwing an exception when it already exists, so that output is not overwritten.

Implementations which write to filesystems which support delegation tokens usually collect the tokens for the destination path(s) and attach them to the job configuration.

Specified by:

checkOutputSpecs in interface OutputFormat<K extends DBWritable,V>

job - job configuration.

Throws:

IOException - when output should not be attempted

getRecordWriter

public RecordWriter<K,V> getRecordWriter(FileSystem filesystem,
 JobConf job,
 String name,
 Progressable progress)
                                  throws IOException

Get the RecordWriter for the given job.

Specified by:

getRecordWriter in interface OutputFormat<K extends DBWritable,V>

job - configuration for the job whose output is being written.

name - the unique name for this part of the output.

progress - mechanism for reporting progress while writing to file.

Returns:

a RecordWriter to write the output for the job.

Throws:

IOException

setOutput

public static void setOutput(JobConf job,
 String tableName,
 String... fieldNames)

Initializes the reduce-part of the job with the appropriate output settings

Parameters:

job - The job

tableName - The table to insert data into

fieldNames - The field names in the table.

setOutput

public static void setOutput(JobConf job,
 String tableName,
 int fieldCount)

Initializes the reduce-part of the job with the appropriate output settings

Parameters:

job - The job

tableName - The table to insert data into

fieldCount - the number of fields in the table.