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From Łukasz Mielicki <>
Subject Re: reduce order vs descending
Date Wed, 23 Feb 2011 19:22:21 GMT
2011/2/23 Paul Davis <>:
> 2011/2/23 Łukasz Mielicki <>:
>> Hi everybody,
>> I can observe that order of values provided to reduce function depends
>> on descending query parameter.
>> Is this a bug?  Or does Couch support left and right reduce separetely?

> Never write code that depends on the ordering of keys in reductions.
> It will break. The order is undefined and I don't ever see it being
> defined due to lots and lots of edge cases in that code.

I pretty confident about my use-case properties. It is similar to
finding max value(s), but in my case key/id matters because they
contain information (I'm not using UUIDs). The remaining questions is
if do I have to sort them in reduce step given descending is always

IMHO its vital to be able to get both left-reduce and right-reduce
semantics over key range.


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