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"Views only operate on the original pool of documents, and are not able to be a view of views." The inability to chain map/reduce calls is the biggest thing ho

"Views only operate on the original pool of documents, and are not able to be a view of views." The inability to chain map/reduce calls is the biggest thing holding CouchDB back, particularly w.r.t. CouchApps that don't have the luxury of an easy workaround. There is a bug https://issues.apache.org/jira/browse/COUCHDB-249 https://issues.apache.org/jira/browse/COUCHDB-249 however no progress has been made recently. By allowing views on the output of other views, more "normalized" document structures could exist that would still be transformable into useful outputs.

eldenbishop 16y ago
Cloudant has a very cool couchdb fork that uses a dynamo style k/v layer that then uses couchdb as its storage engine. They implement chained map/reduce with the caveats that A) the chained m/r is generated async, so it is always out of data a bit and B) I never got it working in their hosted product. I checked them out for the chained M/R but was really wowed by the scale out capable with their system. The dynamo layer takes care of sharding, migrating shards, re-reducing parallel queries etc.