hadoop-common-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From tienduc_dinh <tienduc_d...@yahoo.com>
Subject General questions about Map-Reduce
Date Sun, 11 Jan 2009 13:50:50 GMT


I have some questions about Map-Reduce that I'm not sure, hope that you guys
can help me.

- Does Map-Reduce support parallel writing/reading ? 

I think not because I don't find anything like that in the source code. And
why the data of a input file are distributed on many data-nodes but the
parallel concept isn't used.

- What happens after the Map-Reduce operation ?

I got the first example on

So after the Map-Reduce operation we got

< Bye, 1>
< Goodbye, 1>
< Hadoop, 2>
< Hello, 2>
< World, 2> 

But how can I know that the input file will be written/read correctly on the
file system ?

Any help will be appreciated, thanks.

Tien Duc Dinh

View this message in context: http://www.nabble.com/General-questions-about-Map-Reduce-tp21399361p21399361.html
Sent from the Hadoop core-user mailing list archive at Nabble.com.

View raw message