Neil Harris wrote:
Perhaps the rating code could be turned on only for admins, or users with usernames beginning with 'E' to 'J', or only during non-busy hours... or automatically turned off if load rises over a pre-set limit?
Or perhaps just turned on for a few hours one weekend, to see what the effect on load really is?
Jimbo's plan calls for everyone being able to rate, including not-logged-in users. This will be for test purposes only; the ratings from the test phase will be deleted again, once the statistics people got their hands on it and can hopefully tell us how to fine-tune the rating process.
The "performance hog myth" dates back to the very first version. I have worked on the problematic parts and IMHO they should be good. I can't be certain without real testing, though. However, I doubt it will degrade performance in the initial phase; if there's a problem, it will most likely show once there are at least a few hundred thousand ratings. There will be many write/delete queries on the table, which might lead to table locks; this might be countered with low priority queries, though.
Magnus