On Tue, Feb 10, 2009 at 02:31:58PM -0800, James Marca wrote: > I have a situation where I want to run two different reduce functions > on the output of a single map function. Like suppose I want one > reduce function to get the count of all objects in each group (for > example, documents with or without attachments), and another reduce to > compute some other aggregate, like the average and standard deviation > of a value, (like the average size of attached documents). (Yes, I > know this is a stupid example, as the averaging reduce function will > also have the count, but my real case is too complicated to write > easily).
I believe reduce values are any JSON object, so perhaps you could reduce to an array of values, e.g. [count, total, sum_of_squares] The final calculation of average and SD could then be left to the client
