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From SEGALIS Morgan <msega...@gmail.com>
Subject Re: Cassandra row ordering best practice Modeling
Date Thu, 22 Jan 2015 20:30:20 GMT
Oh yeah, I though about it, even raised the reflexion on the first mail,

"Let's say I want to show only 100 of the newer articles, I'll get the
today's articles, and if it does not fill the request (too few articles),
I'll check the day before that, etc..."

but your answer raised another issue I did not though of before :
- going back on previous days, let's say I want 100 newest articles
- If there is at most 1 article per day, and some 0, I will have do more
100+ queries to get all the posts, won't it be a little too much ?

2015-01-22 20:47 GMT+01:00 DuyHai Doan <doanduyhai@gmail.com>:

> well, if the current day bucket does not contain enough article, you may
> need to search back in the previous day. If the previous day does not have
> any article, you may need to go back time a day before ... and so on ...
>
>  Of course it's a corner case but I've seen some code that misses this
> scenario and ends up in an infinite loop back in time ...
>
> On Thu, Jan 22, 2015 at 8:41 PM, SEGALIS Morgan <msegalis@gmail.com>
> wrote:
>
>> Hi DuyHai,
>>
>> if there is 0 article, the row will obviously not exist I guess... (no
>> article insertion will create the row)
>> What is bugging you exactly ?
>>
>> 2015-01-22 20:33 GMT+01:00 DuyHai Doan <doanduyhai@gmail.com>:
>>
>>> Hello Morgan
>>>
>>>  The data model looks reasonable. Bucketing by day will help you to
>>> scale. The only thing I can see is how to go back in time to fetch articles
>>> from previous buckets (previous days). It is possible to have 0 article for
>>> a country for a day ?
>>>
>>>
>>> On Thu, Jan 22, 2015 at 8:23 PM, SEGALIS Morgan <msegalis@gmail.com>
>>> wrote:
>>>
>>>> Sorry, I copied/pasted the question from another platform where you
>>>> don't generally say hello,
>>>>
>>>> So : Hello everyone,
>>>>
>>>>
>>>> 2015-01-22 20:19 GMT+01:00 SEGALIS Morgan <msegalis@gmail.com>:
>>>>
>>>>> I have a column family that store articles. I'll need to get those
>>>>> articles from the most recent to the oldest, getting them from Country,
and
>>>>> of course the ability to limit the number of fetched articles.
>>>>>
>>>>> I though about another ColumnFamily "ArticlesByDateAndCountry" with
>>>>> dynamic columns
>>>>>
>>>>> The Key would a mix from the 2 Char country Code (ISO 3166-1), and the
>>>>> articles day's date so something like : US-20150118 or FR-20141230 --
>>>>> (XX-YYYYMMDD)
>>>>>
>>>>> In those Row, the column name would be the timeuuid of the article,
>>>>> and the value is the article's ID.
>>>>>
>>>>> It would probably get a thousand of articles per day for each country.
>>>>>
>>>>> Let's say I want to show only 100 of the newer articles, I'll get the
>>>>> today's articles, and if it does not fill the request (too few articles),
>>>>> I'll check the day before that, etc...
>>>>>
>>>>> Is that the best practice, or does someone has a better idea for this
>>>>> purpose ?
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Morgan SEGALIS
>>>>
>>>
>>>
>>
>>
>> --
>> Morgan SEGALIS
>>
>
>


-- 
Morgan SEGALIS

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