mapreduce - Does CouchDB really split views across servers? -

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i'm delving couchdb, , puzzled distribution of map-reduce computations in views. see lot of resources mentioning map-reduce inherently distributed, because can process 1 half of data on server a, other half on server b, , reduce both results. 1 example slide 16 of presentation:

http://www.slideshare.net/gabriele.lana/couchdb-vs-mongodb-2982288

this seems logical, but:

  • couchdb not seem provide api dispatching computations several servers. distribution appears provide replication of entire data set other servers (which then, assume, compute own view data).

  • couchdb uses b-tree store view data based on keys generated in map step of view algorithm, precludes appropriate partitioning of documents based on server should on.

so, couchdb distribute map-reduce computations @ all? or map-reduce property used merely cache values in b-tree nodes?

you looking bigcouch, enables couchdb cluster , uses distributed mapreduce.


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