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MapReduce >> mail # user >> Reducers without output files


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Re: Reducers without output files
Akro
     To add on, if you want to ignore  the key part then substitute key with NullWritable. And do the desired modification in driver class in place of output key type.
 
Hope it helps
Regards
Bejoy K S

-----Original Message-----
From: [EMAIL PROTECTED]
Date: Thu, 15 Sep 2011 04:09:12
To: <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Reducers without output files

Hi Akro
       You can achieve the same within the existing mapreduce frame work itself. Give a NullWritable in place of reducer output value in reduce function. In your driver class as well mention the output value type as NullWritable.

------Original Message------
From: Arko Provo Mukherjee
To: [EMAIL PROTECTED]
ReplyTo: [EMAIL PROTECTED]
Subject: Reducers without output files
Sent: Sep 15, 2011 08:56

Hello Everyone,

I have a small issue with my Reducer that I am trying to figure out
and wanted some advice.

In the reducer, when writing to the output file as declared in
FileOutputFormat.setOutputPath() I want to write only the key and not
the value when I am calling output.collect().

Is there a way I can ignore the key part?

Else,

Can I write a Reducer function that doesn't do a output.collect()??

Say I omit the FileOutputFormat.setOutputPath() in the Driver Class.

I can then manually write the output to HDFS in the format I like.

Is this legal way to do stuff?

Many thanks in advance!
Warm Regards
Arko
Regards
Bejoy K S
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB