On Thu, Oct 30, 2008 at 6:35 PM, Ben Nevile <[EMAIL PROTECTED]> wrote: > > So let's say we've implemented a word count. We have a nice view that is > indexed by word, so we can query any word and find out how many times it > appears. But if we want to know what words are the most frequent, seems to > me that currently we're out of luck.
Ben, You're right that sorting on reduce values is not part of the current feature set. Here is how I've done that work in the past: First, define just a map view, such that you'd like the reduce to be performed on rows which have the same key. Then use the key_reduce function from this code (or write your own) http://github.com/jchris/couchrest/tree/master/lib/couchrest/helper/pager.rb The idea is that this code pages through the view, yielding each key and all of the values that are associated with it. You could do whatever you like with this data. I define a "reduce" function in ruby, and save it's output as documents in another database. Eg if you're data is in my-db, then key_reduce into my-db-reduce. Then you can define another set of map (and/or reduce) views on my-db-reduce, which will sort the keys by a reduce value. There are some missing features here. Chiefly this code is not all that documented, and I'm certain parts of it could use more convention and less ad-hoc decision making on the part of the user. But the really big feature here would be incremental reduce. It's just a matter of bookkeeping really, but it's not yet implemented. Perhaps next time I have a novel use for key_reduce I'll get it working incrementally. Hope this helps. -- Chris Anderson http://jchris.mfdz.com
