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From Sébastien Druon <sdr...@spotuse.com>
Subject Re: N to N relationships
Date Thu, 09 Dec 2010 18:02:58 GMT
```I mean if I have secondary indexes. Apparently they are calculated in the
background...

On 9 December 2010 18:33, David Boxenhorn <david@lookin2.com> wrote:

> What do you mean by indexing?
>
> On Thu, Dec 9, 2010 at 7:30 PM, Sébastien Druon <sdruon@spotuse.com>wrote:
>
>> Thanks a lot for the answer
>>
>> What about the indexing when adding a new element? Is it incremental?
>>
>> Thanks again
>>
>>
>> On 9 December 2010 14:38, David Boxenhorn <david@lookin2.com> wrote:
>>
>>> How about a regular CF where keys are N@N ?
>>>
>>> Then, getting a matrix row would be the same cost as getting a matrix
>>> column (N gets), and it would be very easy to add element N+1.
>>>
>>>
>>> On Thu, Dec 9, 2010 at 1:48 PM, Sébastien Druon <sdruon@spotuse.com>wrote:
>>>
>>>> Hello,
>>>>
>>>> For a specific case, we are thinking about representing a N to N
>>>> relationship with a NxN Matrix in Cassandra.
>>>> The relations will be only between a subset of elements, so the Matrix
>>>> will mostly contain empty elements.
>>>>
>>>> We have a set of questions concerning this:
>>>> - what is the best way to represent this matrix? what would have the
>>>> best performance in reading? in writing?
>>>>   . a super column family with n column families, with n columns each
>>>>   . a column family with n columns and n lines
>>>>
>>>> In the second case, we would need to extract 2 kinds of information:
>>>> - all the relations for a line: this should be no specific problem;
>>>> - all the relations for a column: in that case we would need an index
>>>> for the columns, right? and then get all the lines where the value of the
>>>> column in question is not null... is it the correct way to do?
>>>> When using indexes, say we want to add another element N+1. What impact
>>>> in terms of time would it have on the indexation job?
>>>>
>>>> Thanks a lot for the answers,
>>>>
>>>> Best regards,
>>>>
>>>> Sébastien Druon
>>>>
>>>
>>>
>>
>

```
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