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From Raghu Angadi <rang...@yahoo-inc.com>
Subject Re: Overhead of Java?
Date Wed, 05 Sep 2007 21:30:33 GMT

I would say biggest difference between a C-Hadoop and Java-Hadoop would 
be memory usage on Namenode (and memory allocation related cpu 
benifits). Rest of the nodes on the cluster would perform about the 
same. C is more suitable for low level memory optimizations (both in 
overall size and number of allocations). In my guestimate, Namenode 
could use 30-40% less memory.

Note that memory is an issue mainly for very large clusters.


Steve Schlosser wrote:
> Please excuse a possibly heretical question...
> My colleagues and I have been working with Hadoop lately, and I keep
> getting asked the same question: what is the performance impact of
> having the system written in Java?  Some folks, even today, are
> suspicious of the overhead of Java, especially for systems
> programming.  I realize that an apples-to-apples comparison of
> Java-based Hadoop to, say, C-based Hadoop is entirely out of the
> question, but I was wondering if anyone has a reasonable qualitative
> answer that I can pass on when people ask.
> Thanks!
> -steve

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