hadoop-streaming

问题 Trying to run a mapreduce job on Hadoop using Streaming. I have two ruby scripts wcmapper.rb and wcreducer.rb. I'm attempting to run the job as follows: hadoop jar hadoop/contrib/streaming/hadoop-streaming-1.2.1.jar -file wcmapper.rb -mapper wcmapper.rb -file wcreducer.rb -reducer wcreducer.rb -input test.txt -output output This results in the following error message at the console: 13/11/26 12:54:07 INFO streaming.StreamJob: map 0% reduce 0% 13/11/26 12:54:36 INFO streaming.StreamJob: map

问题 I have data of format in pig {(group, productId, count)} . Now I want to get maximum count in each group and the output might look as follows {(group, productId, maxCount)} . Here is the sample input data (south America,prod1, 45),(south America,prod2, 36), (latin america, prod1, 48),(latin america, prod5,35) here is the output for this input look like (south america, prod1, 45) (North America, prod2, 36) (latin america, prod1, 48) can someone help me on this. 回答1: Based on your sample input

问题 By default, hadoop map tasks write processed records to files in temporary directory at ${mapred.output.dir}/_temporary/_${taskid} . These files sit here until FileCommiter moves them to ${mapred.output.dir} (after task successfully finishes). I have case where in setup() of map task I need to create files under above provided temporary directory, where I write some process related data used later somewhere else. However, when hadoop tasks are killed, temporary directory is removed from HDFS.

问题 I am new to hadoop. I followed the maichel-noll tutorial to set up hadoop in single node.I tried running WordCount program. This is the code I used: import java.io.IOException; import java.util.StringTokenizer; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer;

问题 I'm a newcomer to Ubuntu, Hadoop and DFS but I've managed to install a single-node hadoop instance on my local ubuntu machine following the directions posted on Michael-Noll.com here: http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/#copy-local-example-data-to-hdfs http://www.michael-noll.com/tutorials/writing-an-hadoop-mapreduce-program-in-python/ I'm currently stuck on running the basic word count example on Hadoop. I'm not sure if the fact I've been

问题 Problem: When I submit a job to my hadoop 2.2.0 cluster it doesn't show up in the job tracker but the job completes successfully. By this I can see the output and it is running correctly and prints output as it is running. I have tried muliple options but the job tracker is not seeing the job. If I run a streaming job using the 2.2.0 hadoop it shows up in the task tracker but when I submit it via the hadoop-client api it does not show up in the job tracker. I am looking at the ui interface on

问题 Hey I'm fairly new to the world of Big Data. I came across this tutorial on http://musicmachinery.com/2011/09/04/how-to-process-a-million-songs-in-20-minutes/ It describes in detail of how to run MapReduce job using mrjob both locally and on Elastic Map Reduce. Well I'm trying to run this on my own Hadoop cluser. I ran the job using the following command. python density.py tiny.dat -r hadoop --hadoop-bin /usr/bin/hadoop > outputmusic And this is what I get: HADOOP: Running job: job

问题 Error: hadoop_admin@ubuntu:~/hadoop$ bin/hadoop jar /home/hadoop_admin/hadoop/contrib/streaming/hadoop-0.20.0-streaming.jar -input data -output DOUT -mapper /home/balachanderp/libsvm-hadoop-master/scripts/mapperLibsvm.py -reducer /home/balachanderp/libsvm-hadoop-master/scripts/reducerLibsvm.py -file /home/balachanderp/libsvm-hadoop-master/scripts/mapperLibsvm.py -file /home/balachanderp/libsvm-hadoop-master/scripts/reducerLibsvm.py packageJobJar: [/home/balachanderp/libsvm-hadoop-master

问题 I am using Hadoop streaming JAR for WordCount , I want to know how can I get Globally Sort , according to answer on another question in SO, I found that when we use of just one reducer we can get Globally sort but in my result with numReduceTasks=1 (one reducer) it is not sort. For example, my input to mapper is: file 1: A long time ago in a galaxy far far away file 2: Another episode for Star Wars Result is: A 1 a 1 Star 1 ago 1 for 1 far 2 away 1 time 1 Wars 1 long 1 Another 1 in 1 episode

问题 Facing duplicate entry problem while inserting to the table. I have been used Hadoop mapper for reading record from file.It success fully reads record from file.But while writing the record to mysql data base by Hadoop reducer, following error occured. java.io.IOException: Duplicate entry '505975648' for key 'PRIMARY' But Mysql table is remains empty.Unable to write the record to mysql table from Hadoop DBWritable reducer. Following is error log: WARNING: com.mysql.jdbc.exceptions.jdbc4