org.apache.tez.examples

Class HashJoinExample

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.tez.examples.HashJoinExample

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable, org.apache.hadoop.util.Tool

public class HashJoinExample
extends org.apache.hadoop.conf.Configured
implements org.apache.hadoop.util.Tool

Simple example of joining 2 data sets using Hash Join.
The example shows a vertex with multiple inputs that represent the two data sets that need to be joined. This HashJoinExample assume that keys in the second dataset (hashSide) is unique.
The join can be performed using a broadcast (or replicate-fragment) join in which the small side of the join is broadcast in total to fragments of the larger side. Each fragment of the larger side can perform the join operation independently using the full data of the smaller side. This shows the usage of the broadcast edge property in Tez.
The join can be performed using the regular repartition join where both sides are partitioned according to the same scheme into the same number of fragments. Then the keys in the same fragment are joined with each other. This is the default join strategy.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HashJoinExample.ForwardingProcessor Reads key-values from the source and forwards the value as the key for the output
static class	HashJoinExample.HashJoinProcessor Join 2 inputs using Hash Join algorithm.

Constructor Summary

Constructors

Constructor and Description
HashJoinExample()

Method Summary

Methods

Modifier and Type	Method and Description
static void	main(String[] args)
int	run(org.apache.hadoop.conf.Configuration conf, String[] args, org.apache.tez.client.TezClient tezClient)
int	run(String[] args)

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Constructor Detail

HashJoinExample

public HashJoinExample()

Method Detail

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception

run

public int run(String[] args)
        throws Exception

Specified by:

run in interface org.apache.hadoop.util.Tool

Throws:

Exception

run

public int run(org.apache.hadoop.conf.Configuration conf,
      String[] args,
      org.apache.tez.client.TezClient tezClient)
        throws Exception

Throws:

Exception