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From Jonathan Hsieh <...@cloudera.com>
Subject Re: Rowkey, Consistant Hashing, MD5?
Date Mon, 21 Jul 2014 17:52:32 GMT
Just to be clear, are you sure you need consistent hashing for your row
key? These kinds of hashes are generally used for systems where load
balancing is done via distributed hashtables.  HBase doesn't need this
internally since it does range partitioning (and thus load balancing
doesn't need a hash).

You could implement you own consistent has built upon md5.  I hacked
together a version of this that used md5 a long time ago here [1], [2].
 YMMV.

[1]
https://github.com/jmhsieh/algorithms/tree/master/src/main/java/org/jmhsieh/sets/consistant
[2]
https://github.com/jmhsieh/algorithms/tree/master/src/test/java/org/jmhsieh/sets/consistant

Jon.


On Mon, Jul 21, 2014 at 7:18 AM, Mingtao Zhang <mail2mingtao@gmail.com>
wrote:

> Hi,
>
> I am trying to find a consistant hasing algorithm for the first portion of
> the row key.
>
> I saw the document/book that MD5 is mentioned everything.
>
> But I have trouble to persuade myself that MD5 (
> http://en.wikipedia.org/wiki/MD5) is considered as consistant hasing.
>
> Could any of you point me to the library contains the hashing you are
> using?
>
> Thanks in advance!
>
> Best Regards,
> Mingtao
>



-- 
// Jonathan Hsieh (shay)
// HBase Tech Lead, Software Engineer, Cloudera
// jon@cloudera.com // @jmhsieh

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