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Date: Fri, 9 Sep 2011 16:39:16 -0700
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 <CAGpTDNc0BwKr=DiY5YXLJyPKWB_ju+KpnVcTkZ9Hq2a8wGEavQ@mail.gmail.com>
Subject: Re: Using multiple column families
From: Jean-Daniel Cryans <jdcryans@apache.org>
To: user@hbase.apache.org
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20k rows? If this is your only use case, you don't need HBase :)

If it's 20k rows times a gazillion columns per row, then I would
recommend flattening out the rows instead.

If it's just one small table among others, then you probably won't be
bothered by the multiple families.

J-D

On Thu, Sep 8, 2011 at 10:07 PM, Imran M Yousuf <imyousuf@gmail.com> wrote:
> Hi,
>
> Firstly, I have read in the mailing list before that having more than
> 1 column family is not recommended. I am more interested to know
> whether it is a problem in my use case as well or not.
>
> I have a strong entitly and it has 6 weak entities all with 1-to-many
> cardinal relationship to the strong entity. Furthermore, they are all
> loaded in mutually exclusive manner, i.e. if A is strong entity and
> its weak entities are P, Q, R, S, T, U in that case no 2 weak entities
> are accessed at once. Moreover their lifecycles are independent of
> each other. My current implementation is I have one column family for
> the strong entity and one for each weak entities. So for a given row I
> only load one column family at a time. The obvious advantages are that
> - deleting strong entity automatically deletes the weak entities as
> they are a single row, delete all of a kind weak entity for a specific
> weak entity is as simple as deleting all cells in a column family for
> a row. Our assumption (pretty high than what we expect) is that we
> will not have more than 20k rows in that table. Under these
> circumstance how bad is it to have 7 column families?
>
> We would be glad if you would kindly share thoughts and feedback on this issue.
>
> Thank you,
>
> --
> Imran M Yousuf
> Entrepreneur & CEO
> Smart IT Engineering Ltd.
> Dhaka, Bangladesh
> Twitter: @imyousuf - http://twitter.com/imyousuf
> Blog: http://imyousuf-tech.blogs.smartitengineering.com/
> Mobile: +880-1711402557
>