I realize this is probably a joke, but the relative infrequency of rating, the fact that this rating algorithm only requires information from the local context[1], and the existence of caching means that this is very, very unlikely to be the bottleneck for any site.
[1] i.e. to calculate Harry Potter's rating you only need to know about Harry Potter, not every other book ever printed
Re:How Not To Sort By Average Rating
by jackowayed on Friday February 13, 2009 @03:51PM
(#480392)
yeah, you could cache it in the db until you get a new rating.
It would still slow you down a little though.
And yes, it was a joke :-)
Or, "How to Make Your Host Very Happy Because You Suddenly Have to Move Up To a Server With Double the Processing Cycles"