A Count(*) View for CouchDB
I've been working with CouchDB a lot lately.  The first thing I tried to do, after I loaded 1,000,000 records, is to do the equivalent of 
count(*).  Below is the view I used to implement a "count how many records I have in this database" or "count all":
{ "_id": "_design/counts",
  "language": "javascript",
  "views": {
    "all": {
      "map": "function(doc) { emit(null, 1); }",
      "reduce": "function(keys, values, combine) { return sum(values); }"
    }
  }
}