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From Imran M Yousuf <imyou...@gmail.com>
Subject Re: Using multiple column families
Date Sat, 10 Sep 2011 01:25:12 GMT
Hi J-D,

Thanks for your feedback.

(replies inline)
On Sat, Sep 10, 2011 at 5:39 AM, Jean-Daniel Cryans <jdcryans@apache.org> wrote:
> 20k rows? If this is your only use case, you don't need HBase :)
>

Its one of several others

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

Well, our guess is at the moment their would not be more than 500
cells per family to start with.

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

We actually have many other tables which are flattened out to a single
column family and this is one table for which we are using more than 1
column family.

Thanks once again.

Imran

> 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
>>
>



-- 
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

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