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Published on 2010-05-14T14:31:37Z
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Hi,
I tried printing out values using System.out.println(), but they won't appear on the console. How do i print out the values in a map/reduce application for debugging purposes using Hadoop?
Thanks, Deepak.
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i am willing to learn hadoop as a Developer , but i am confused over the prerequisite of learning it.? is having a good experience in java programming very essential to learn hadoop? I have 4 years of experience in application development in LAMP.
But i am not in touch with java programming as a part…
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Full list of error:
hb@localhost:/etc/hadoop/conf$ sudo service hadoop-hdfs-namenode start
* Starting Hadoop namenode:
starting namenode, logging to /var/log/hadoop-hdfs/hadoop-hdfs-namenode-localhost.out
12/09/10 14:41:09 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG:…
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Introduction
An attempt to combine HBase and HDFS results in the following:
2014-06-09 00:15:14,777 WARN org.apache.hadoop.hbase.HBaseFileSystem: Create Dir
ectory, retries exhausted
2014-06-09 00:15:14,780 FATAL org.apache.hadoop.hbase.master.HMaster: Unhandled
exception. Starting shutdown.
java…
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I compiling with Solaris 10 SPARC, jdk 1.6 from Sun, Ant 1.7.1 from OpenCSW.
I have no problem running hadoop 0.17.2.1
However, I have problem compiling/integrating hive with the error 'cannot find symbol', although I followed the tutorial.
I have the hive source code from SVN exactly from tutorial…
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I'm new to hadoop and is in learning phase.
As per Hadoop Definitve guide, i have set up my hadoop in pseudo distributed mode and everything was working fine. I was even able to execute all the examples from chapter 3 yesterday. Today, when i rebooted my unix and tried to run start-dfs.sh and then…
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In many real-life situations where you apply MapReduce, the final algorithms end up being several MapReduce steps.
I.e. Map1 , Reduce1 , Map2 , Reduce2 , etc.
So you have the output from the last reduce that is needed as the input for the next map.
The intermediate data is something you (in general)…
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When I executed a MapReduce program in Eclipse using Hadoop, I got the below error.
It has to be some change in path, but I'm not able to figure it out.
Any idea?
16:35:39 INFO mapred.JobClient: Task Id : attempt_201001151609_0001_m_000006_0, Status : FAILED
java.io.FileNotFoundException: File C:/tmp/hadoop-Shwe/mapred/local/taskTracker/jobcache/job_201001151609_0001/attempt_201001151609_0001_m_000006_0/work/tmp…
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Hello,
I would like to convert the following Java program to a MapReduce job. I have read about MapReduce and feel like this would be a good problem to solve using it, but I cannot figure out what to do.
This basically loops through a directory of html files and parses them into a CSV file.
http://www…
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Could mapreduce be used to implement a webserver?
I'm thinking something like when a request comes in then the request sits on a queue, until a server is free to process it? Or am I missing the point here?
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In yesterday’s blog post we learned what is Hadoop. In this article we will take a quick look at one of the four most important buzz words which goes around Big Data – MapReduce.
What is MapReduce?
MapReduce was designed by Google as a programming model for processing large data sets with…
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