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From Jan Lehnardt <...@apache.org>
Subject Re: Sorting views with composite keys
Date Sun, 05 Oct 2008 19:21:04 GMT
In my defense :)

My suggestion was a 3 minute hack that was done without
much thinking. If we want to go that route, we'd need to
add more sorting handlers for other data types. this could
go into a view-JS standard library (like sum()).

the use-case was just having the sorting by first and second key,
but only ever query on the first one.

I'm not claiming that this is a stellar idea, only one that might
be feasible for a specific use case.

Cheers
Jan
--

On Oct 5, 2008, at 20:48 , Chris Anderson wrote:

> yeah you'd have to preprocess the keys with a similar function..
>
> I think the use case is that you'd query based on the front key, and a
> count, so as to get, say the last 10 alphabetical tags for a given
> user.
>
> Come to think of it, I'm not sure what sense there is in doing this.
> Why not just use a regular collation, and if you have more per
> front-key than you can fit in ram, just page through the front key's
> second key in reverse...
>
>
> On Sun, Oct 5, 2008 at 11:35 AM, Ayende Rahien <ayende@ayende.com>  
> wrote:
>> How does querying those works?I mean, the keys wouldn't match,  
>> would they?
>>
>> On Sun, Oct 5, 2008 at 8:26 PM, Chris Anderson <jchris@apache.org>  
>> wrote:
>>
>>> Jan posted this to the IRC channel.
>>>
>>> http://friendpaste.com/rc9CcxUW
>>>
>>> I supposed you'd have to write a reverse method for each JS  
>>> primitive
>>> type, if you wanted to be completely flexible.
>>>
>>>
>>> On Sun, Oct 5, 2008 at 9:25 AM, Nick Johnson <arachnid@notdot.net>  
>>> wrote:
>>>> How would I construct a view with two keys, a and b, sorted first  
>>>> by a
>>>> ascending, then by b descending? Composite keys are easy enough to
>>> generate,
>>>> but the key [a,b] would only permit sorting both in ascending  
>>>> order (or
>>> both
>>>> in descending order, if we scan in reverse). Can anyone suggest a  
>>>> way of
>>>> modifying the keys to support heterogenous sort orders like this?  
>>>> My best
>>>> idea so far is a monstrosity involving hex-encoded binary data. :)
>>>>
>>>
>>>
>>>
>>> --
>>> Chris Anderson
>>> http://jchris.mfdz.com
>>>
>>
>
>
>
> -- 
> Chris Anderson
> http://jchris.mfdz.com
>


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