Map / Reduce and many many things :-)

Immediately I warn you did not know where to publish. I strongly doubt the correctness of the choice :-)

There is a set of documents c creation date.
Sort them by creation date.
Documents can a) be added, and only at the beginning (that is, the most recent), b) are deleted.
How to make, for example in Apache CouchDB, paginal output?
Your suggestions?

What is Apache CouchDB read on the official page and on the habr . About map reduce read in the wiki and in the original article Google.