Hi Matthew,
I have a same problem here (see
http://www.listware.net/201009/hadoop-common-user/81228-return-a-parameter-using-map-only.html).
I was planning to use join mapper (or mapper chain) to handle two
different inputs. The problem was the mapper seems cannot return value
directly to each other. Then I have to find out the best settings in
heap table, MongoDB, memcached, TokyoCabinet, MapFile, etc. etc. to let
the multiple mappers talk efficiently.
Shi
On 2010-10-14 9:03, Matthew John wrote:
Hi all ,
I have been recently working on a task where I need to take in two input
(types) files , compare them and produce a result from it using a logic.
But as I understand simple MapReduce implementations are for processing a
single input type. The closest implementation I could think of similar to my
work is Join MapReduce. But I am not able to understand much from the
example provided in Hadoop .. Can someone provide a good pointer to such
multiple input data processing ( or Join ) in mapreduce . It will also be
great if you can send in some sample code for the same.
Thanks ,
Matthew
--
Postdoctoral Scholar
Institute for Genomics and Systems Biology
Department of Medicine, the University of Chicago
Knapp Center for Biomedical Discovery
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