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From: Matteo Caprari <matteo.caprari@gmail.com>
Date: Tue, 16 Mar 2010 10:16:54 +0000
Message-ID: <1bca98391003160316j4c190bd0j61475d26f58dfc55@mail.gmail.com>
Subject: Cassandra and hadoop?
To: user@cassandra.apache.org
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Hi.

I've tried the mapreduce example in 0.6 contrib/wordcount and it
worked very well.

I have a shallow understanding of both worlds, so pardon my questions:

Is the integration with hadoop just 'semantic' (ie map/reduce api is
only used as query abstraction) or is
it 'structural' (ie cassandra can 'talk to hadoop' and replace HDFS as
input source)?

In practice:
- If I want to run a distributed mapreduce job on cassandra, does my
cassandra cluster have to be an hadoop cluster as well?
- do I get data locality optimization: I reckon cassandra can in
principle figure out where it is best to execute a
SlicePredicate/Mapper,
but to do so it should take over some of the responsibilities of
hadoop's jobtracker. Does it?

Thanks.
-- 
:Matteo Caprari
matteo.caprari@gmail.com