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From Paul J Davis <>
Subject Re: Any sort order guarantee for key (value) argument of CouchDB reduce function?
Date Tue, 06 Nov 2012 13:05:28 GMT
No, there aren't any guarantees. And rereduce can end up getting passed some surprising (to
me when I tried relying on ordering at least) sets of keys. 

On Nov 6, 2012, at 1:55 PM, Vladislav Ponomarev <> wrote:

> Hello,
> Per CouchDB guide, the reduce function signature looks like this:
> function (key, values, rereduce) {
>    return ...; // some calculations happen here
> }
> where the definition of first arguments is as follows:
>> when rereduce is false, then:
>>   - key will be an array whose elements are arrays of the form [key,id],
>>   where key is a key emitted by the map function and id is that of the
>>   document from which the key was generated.
>>   - values will be an array of the values emitted for the respective
>>   elements in keys.
> My question is: when rereduce is false, are there any guarantees regarding
> the order of key (or values) array elements? My gut feel (based on Reduce
> vs Rereduce chapter) is that keys, and respectively values, should be
> ordered, but I do not see any direct confirmation.
> Any ideas? Thank you!

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