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Date: Tue, 27 Mar 2012 20:21:37 +0100
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Subject: Re: Sorting CouchDB data using couch-lucene
From: Robert Newson <rnewson@apache.org>
To: user@couchdb.apache.org
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We can only guess what Jason had in mind at step 3.

Lucene can sort by any appropriately indexed field but here, as in the
single-pass map/reduce view, the value you want is not available.

I think someone had a crack at chained map-reduce other than Cloudant
but I don't recall the project name. Also, I know Benoit is working on
adding a _changes feed for views, which should allow chained m-r too.

B.

On 27 March 2012 18:28, nicholas a. evans <nick@ekenosen.net> wrote:
> On Tue, Mar 27, 2012 at 1:14 PM, Robert Newson <rnewson@apache.org> wrote=
:
>> cross-posting is generally bad form as it splits the conversation. If
>> I answer here or on SO, someone potentially loses out.
>
> Good point. =A0Sorry about that.
>
>> That said, couchdb-lucene is an independent index, sourced from the
>> database. As such, it has no access to the reduced values nor does it
>> have an equivalent feature. Where did you see that suggestion?
>
> I saw that suggestion at http://stackoverflow.com/a/2821476/110681
>
> I think the idea wasn't so much that couchdb-lucene would read from
> the view as much that couchdb-lucene would give me a completely
> different way to approach the problem. =A0Is there some way for lucene
> to index the data so that it could give me ranked results? =A0E.g. if
> every document has a doc.sender, is there some way to store the
> senders in lucene and then ask for a ranking of senders with their
> counts? =A0I don't know enough about lucene or full-text indexing in
> general, so I hoped and assumed there might be some way to twist the
> lucene index to do my bidding. =A0:)
>
> If lucene can't help out and no one knows of an open source chained
> map-reduce views implementation, then the polyglot persistence
> approach sounds best to me, since redis zsets are perfect for this
> particular task.
>
> Thanks.
> --
> Nick