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From Ishan Chhabra <ichha...@rocketfuel.com>
Subject Re: Rowkey, Consistant Hashing, MD5?
Date Tue, 22 Jul 2014 02:28:10 GMT
Mingtao,
If I understand correctly, you want to prefix the key with a hash (as
mentioned in the book) to get a good distribution. Use MurmurHash (there is
an implementation in HBase code itself) as it is fast and gives a uniform
distribution.

"Consistent Hashing" is not the correct term to use here if I understand
your intent correctly.


On Mon, Jul 21, 2014 at 2:44 PM, Liam Slusser <lslusser@gmail.com> wrote:

> MD5 isn't a consistent hashing algorithm.  Consistent hashing is a scheme
> that provides a hash table functionality in a way that the adding or
> removing of one slot does not significantly change the mapping of keys to
> slots.  With that said, a lot of consistent hashing algorithms USE
> md5...but it alone won't get you all the way there.
>
> Some light bedtime reading:
> http://en.wikipedia.org/wiki/Consistent_hashing
>
> liam
>
>
> 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
> >
>



-- 
*Ishan Chhabra *| Rocket Scientist | RocketFuel Inc.

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