To store the average rating and count of all ratings for an entity, we use two columns on the associated entity's *_meta table: rating and rating_count.  For example, artists have artist_meta.rating and artist_meta.rating_count.

These columns are currently kept up-to-date by our code whenever a rating is added or updated.  This ticket proposes updating these columns with triggers instead, on the *_rating_raw tables (e.g. artist_rating_raw).

This would have no effect on mirror servers, as triggers are generally not created there.