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From Vick Khera <>
Subject Re: Hadoop over Cassandra
Date Mon, 17 May 2010 21:12:52 GMT
On Mon, May 17, 2010 at 3:46 PM, Jonathan Ellis <> wrote:
> Moving to the user@ list.
> should be useful.

That document doesn't really answer the "is data locality preserved"
when running the map phase, but my hunch is "no".

> On Mon, May 17, 2010 at 2:41 PM, Yan Virin <> wrote:
>> Hi,
>> Can someone explain how this works? As long as I know, there is no execution
>> engine in Cassandra alone, so I assume that Hadoop gives the MapReduce
>> execution engine which uses Cassandra as the distributed storage? Is data
>> locality preserved? How mature this "couple" is? How is the performance of
>> this compared to the original Hadoop over HDFS?

The built-in execution engine is one thing that excites me about the
Riak data store -- the work is done locally to where the data is.
That and you can specify your jobs in javascript, making it that much
easier for web-oriented people :-)  The big drawback for Riak is that
building it for FreeBSD is pretty much impossible.

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