The problem:
I want to allow users to rate things. They do this very very frequently, so I can't store it in the actual document being rated, so I have Rating documents. It's easy enough to write a map/reduce that gives me the computed average rating for a given document, however, it seems to be impossible to get a listing of the highest rated documents, as I can only get the computed rating for a document one at a time.
The possible solutions:- Buffer rating additions, then at a later time, run through them and calculate the new average rating, store it in the document as computed_rating, so I can order on that in the key - Cron a job that goes in and looks for new rating every 5 mins or whatever, and then does the same as the previous solution by storing it in a computed_rating field
I'm not a fan of either of these, because #1 means if my webapp hiccups, I lose ratings, and #2 is just a pain to keep sweeping the db for new Rating documents then going through updating all the documents.
Is there really no other solutions that don't require me to store the computed rating in the doc itself? There's no way I can perhaps order on the value from the map/reduce, rather than only being able to order on the key?
Thanks, Ben
smime.p7s
Description: S/MIME cryptographic signature
