difference between mapper and map runnable

[Rakhi Khatwani <rk...@gmail.com>]

Hi,
        Whats the difference between a mapper and map runnable and its
usage?
Regards
Raakhi

Re: difference between mapper and map runnable

[Arun C Murthy <ac...@yahoo-inc.com>]

On Aug 27, 2009, at 5:25 AM, Rakhi Khatwani wrote:

> Hi,
>        Whats the difference between a mapper and map runnable and its
> usage?

MapRunnable has more control. It has the iterator to the input keys/ 
values...

The new Map-Reduce api (context objects, available in hadoop-0.20  
onwards) you have both MapRunnable and ReduceRunnable.

Arun

RE: difference between mapper and map runnable

[Amogh Vasekar <am...@yahoo-inc.com>]

Hi,
Mapper is used to process the <K,V> pair passed to it, MapRunnable is an interface, when implemented is responsible for generating a conforming <K,V> pair and pass it to Mapper.

Cheers!
Amogh

-----Original Message-----
From: Rakhi Khatwani [mailto:rkhatwani@gmail.com] 
Sent: Thursday, August 27, 2009 5:56 PM
To: common-user@hadoop.apache.org
Subject: difference between mapper and map runnable

Hi,
        Whats the difference between a mapper and map runnable and its
usage?
Regards
Raakhi