Hadoop 0.2: How to read outputs from TextOutputFormat?

Posted by S.N on Stack Overflow See other posts from Stack Overflow or by S.N
Published on 2010-04-09T08:46:42Z Indexed on 2010/04/13 1:02 UTC
Read the original article Hit count: 435

Filed under:

hadoop

|

mapreduce

My reducer class produces outputs with TextOutputFormat (the default OutputFormat given by Job). I like to consume this outputs after the MapReduce job complete to aggregate the outputs. In addition to this, I like to write out the aggregated information with TextInputFormat so that the output from this process can be consumed by the next iteration of MapReduce task. Can anyone give me an example on how to write & read with TextFormat? By the way, the reason why I am using TextFormat, rather Sequence, is the interoperability. The outputs should be consumed by any software.

© Stack Overflow or respective owner

Related posts about hadoop

prerequisites of learnig hadoop, can php developer learn hadoop without java experience [closed]

as seen on Programmers - Search for 'Programmers'
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… >>> More
Hadoop hdfs namenode is throwing an error

as seen on Server Fault - Search for 'Server Fault'
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:… >>> More
Combining HBase and HDFS results in Exception in makeDirOnFileSystem

as seen on Server Fault - Search for 'Server Fault'
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… >>> More
Problem compiling hive with ant

as seen on Stack Overflow - Search for 'Stack Overflow'
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… >>> More
no namenode error in pseudo-mode

as seen on Stack Overflow - Search for 'Stack Overflow'
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… >>> More

Related posts about mapreduce

Chaining multiple MapReduce jobs in Hadoop.

as seen on Stack Overflow - Search for 'Stack Overflow'
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)… >>> More
Error in using Hadoop MapReduce in Eclipse

as seen on Stack Overflow - Search for 'Stack Overflow'
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… >>> More
Help converting java program to MapReduce job

as seen on Stack Overflow - Search for 'Stack Overflow'
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… >>> More
Can a webserver be implemented using mapreduce?

as seen on Stack Overflow - Search for 'Stack Overflow'
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? >>> More
Big Data – Buzz Words: What is MapReduce – Day 7 of 21

as seen on SQL Authority - Search for 'SQL Authority'
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… >>> More