On 14 December 2011 05:46, Dominic Tarr <[email protected]> wrote: > hi, > > I need a iterative map reduce, prefurably, in couchdb. > > I want to be able to do a map reduce to generate unique items, then another > map reduce to generate stats about those unique items. > > from what I know about couchdb at the moment, it seems like id have to do > the first step at the document creation step, which is just ugly. >https://mail.google.com/mail/?shva=1#inbox > has anyone else dealt with this problem?
Hi Dom, Cloudant do this in BigCouch which they released as open source a while back http://support.cloudant.com/kb/views/chained-mapreduce-views there are a few other posts on chained MR around but I don't know of a better Couch-style implementation. Their basic approach is to copy the view output into a new db which you'd then re-MR as required. Rinse and repeat until complete. Depending on your data it might be possible to implement their view->copy to db -> new view approach yourself in native couch. It would be interesting to do this as a couch extension using that nifty plugin interface that hasn't been developed yet! A+ Dave
