Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Hadoop >> mail # user >> probably very stupid question

Copy link to this message
Re: probably very stupid question
Hi Jamal

I believe a reduce side join is what you are looking for.

You can use MultipleInputs and achieve a reduce side join to achieve this.


Bejoy KS

Sent from remote device, Please excuse typos

-----Original Message-----
From: jamal sasha <[EMAIL PROTECTED]>
Date: Mon, 14 Jan 2013 15:44:25
Subject: probably very stupid question

  Probably a very lame question.
I have two documents and I want to find the overlap of both documents in
map reduce fashion and then compare the overlap (lets say I have some
measure to do that)

SO this is what I am thinking:

    1) Run the normal wordcount job on one document (
    2) But rather than saving a file, save everything in a
    3) Pass that HashMap along the second wordcount mapreduce program and
then as I am processing the second document, check the words against the
HashMap to find whether the word is present or not.

So, something like this

     1) HashMap<String, boolean> hm = runStepOne(); <-- map reduce job
     2) runSteptwo(HashMap<String, boolean>)
How do I do this in hadoop
I know there can be some other hacks but what I am trying to achieve is get
comfortable with the java framework..
So, from the above link.. how do i save the datastrcuture instead of file.
How do I pass the datastructure as an argument?