Hadoop: Menjalankan MapReduce Job -WordCount

Sumber: http://wiki.apache.org/hadoop/WordCount

Buat File Data Sederhana

cd ~
touch file01
touch file02
echo "Hello World Bye World" > file01
echo "Hello Hadoop Goodbye Hadoop" > file02

hadoop fs -mkdir /user/hduser/input
hadoop fs -put file* /user/hduser/input/

Cek

hadoop fs -ls /user/hduser/input/

Found 2 items
-rw-r--r--   1 hduser supergroup         22 2015-11-09 17:28 /user/hduser/input/file01
-rw-r--r--   1 hduser supergroup         28 2015-11-09 17:28 /user/hduser/input/file02

hadoop fs -cat /user/hduser/input/file01
Hello World Bye World

hadoop fs -cat /usr/hduser/input/file02
Hello Hadoop Goodbye Hadoop 

Jalankan WordCount

Contoh

cd /usr/local/hadoop
hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar wordcount [-m <#maps>] [-r <#reducers>] <in-dir> <out-dir> 

Jalankan

cd /usr/local/hadoop
hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar wordcount /user/hduser/input /user/hduser/output

Copy Hasil

cd ~
hadoop fs -copyToLocal /user/hduser/output .
more output/part-r-*

Hasilnya

Bye	1
Goodbye	1
Hadoop	2
Hello	2
World	2

Ujicoba menggunakan dataset 10Gbyte

Buat dataset

cd /usr/local/hadoop
hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar randomtextwriter /random-text-data

Analisa

hadoop fs -rm /user/hduser/output/*
hadoop fs -rmdir /user/hduser/output
cd /usr/local/hadoop
hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar wordcount /random-text-data /user/hduser/output

Hasilnya

..
..
..
	Map-Reduce Framework
		Map input records=26777
		Map output records=100840944
		Map output bytes=1522178351
		Map output materialized bytes=74694575
		Input split bytes=1053
		Combine input records=103318240
		Combine output records=4741732
		Reduce input groups=1577165
		Reduce shuffle bytes=74694575
		Reduce input records=2264436
		Reduce output records=1577165
		Spilled Records=7006168
		Shuffled Maps =9
		Failed Shuffles=0
		Merged Map outputs=9
		GC time elapsed (ms)=3255
		Total committed heap usage (bytes)=4048551936
	Shuffle Errors
		BAD_ID=0
		CONNECTION=0
		IO_ERROR=0
		WRONG_LENGTH=0
		WRONG_MAP=0
		WRONG_REDUCE=0
	File Input Format Counters 
		Bytes Read=1102531981
	File Output Format Counters 
		Bytes Written=48884623

Analisa hasil

cd ~
hadoop fs -copyToLocal /user/hduser/output .
more output/part-r-*

Referensi

• http://wiki.apache.org/hadoop/WordCount