I've been working on an open-source tool with a similar approach chaining map-reduce: https://github.com/afters/Couch-Incarnate
The need to pay the bills withheld me from putting more time into it lately, so I can't say it's production quality. Hopefully, this will change soon. Dominic - the method I currently use in production is to poll the changes on my DB every few seconds and update a 'summary' DB accordingly. It's not pretty, but it works. I hope to replace it with Couch-Incarnate asap. Alon On 14 December 2011 10:50, Dave Cottlehuber <[email protected]> wrote: > 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 >
