result of self.update_rank after changing game.total_points to points.total_points

gistfile1.txt

 def self.update_rank_by klass
    rank_class = (klass.name + "Rank").constantize
    rank_by_col  = "#{klass.name.underscore}_id".to_sym
    select_sql = "points.user_id, points.#{rank_by_col}, 
                  SUM(points.points) total_points"
    rank = total_points = 0
    Point.select(select_sql).group(:user_id, rank_by_col).
    order("total_points DESC").find_in_batches do |points|
      User.transaction do
        points.each do |point|
          ro = rank_class.send(
            "find_or_initialize_by_user_id_and_#{rank_by_col}",
            point.user_id, point.send(rank_by_col))
          # calculate rank
          if point.total_points > total_points
            total_points = point.total_points
            rank +=1
          end
          ro.total_points = point.total_points           
          ro.rank = rank
          ro.save
        end
      end      
    end    
  end


Points:
              points  user_id         game_type_id            game_id   
                10      1		1	                1
                10	1		1	                1
                20	2		1	                2
                10	2		1	                2
                25	2		1	                3
                20	2		1	                1		


GameRanks:
        user_id         game_id         total_points    rank
        1               1	        20      	1
        2	        2	        30	        2
        2               3	        25	        2
        2	        1	        20	        2

Expected GameRanks:
        user_id         game_id         total_points    rank
        1               1               20      	1
        2	        2	        30	        1
        2               3	        25	        1
        2	        1	        20	        1


Trace:
irb(main):001:0> User.update_rank
Scoped order and limit are ignored, it's forced to be batch order and batch size
  Point Load (99.0ms)  SELECT points.user_id, points.game_id,
 SUM(points.points) total_points FROM `points` WHERE (`points`.`id` >= 0) GROUP                                                                              BY user_id, game_id ORDER BY `points`.`id` ASC LIMIT 1000
   (0.9ms)  BEGIN
  GameRank Load (0.7ms)  SELECT `game_ranks`.* FROM `game_ranks` WHERE `game_ran                                                                             ks`.`user_id` = 1 AND `game_ranks`.`game_id` = 1 LIMIT 1
  SQL (0.8ms)  INSERT INTO `game_ranks` (`created_at`, `rank`, `game_id`, `total                                                                             _points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 1, 1, 20, '201                                                                             3-03-06 02:22:16', 1)
  GameRank Load (0.6ms)  SELECT `game_ranks`.* FROM `game_ranks` WHERE `game_ran                                                                             ks`.`user_id` = 2 AND `game_ranks`.`game_id` = 2 LIMIT 1
  SQL (0.6ms)  INSERT INTO `game_ranks` (`created_at`, `rank`, `game_id`, `total                                                                             _points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 2, 2, 30, '201                                                                             3-03-06 02:22:16', 2)
  GameRank Load (0.5ms)  SELECT `game_ranks`.* FROM `game_ranks` WHERE `game_ran                                                                             ks`.`user_id` = 2 AND `game_ranks`.`game_id` = 3 LIMIT 1
  SQL (0.5ms)  INSERT INTO `game_ranks` (`created_at`, `rank`, `game_id`, `total                                                                             _points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 2, 3, 25, '201                                                                             3-03-06 02:22:16', 2)
  TeamRank Load (0.5ms)  SELECT `game_ranks`.* FROM `game_ranks` WHERE `game_ran                                                                             ks`.`user_id` = 2 AND `game_ranks`.`game_id` = 1 LIMIT 1
  SQL (0.5ms)  INSERT INTO `game_ranks` (`created_at`, `rank`, `game_id`, `total                                                                             _points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 2, 1, 20, '201                                                                             3-03-06 02:22:16', 2)
   (23.3ms)  COMMIT
Scoped order and limit are ignored, it's forced to be batch order and batch size
  Point Load (1.1ms)  SELECT points.user_id, points.game_type_id,
 SUM(points.points) total_points FROM `points` WHERE (`points`.`id` >= 0) GROUP                                                                              BY user_id, game_type_id ORDER BY `points`.`id` ASC LIMIT 1000
   (0.4ms)  BEGIN
  GameTypeRank Load (0.5ms)  SELECT `game_type_ranks`.* FROM `game_type_ranks` W                                                                             HERE `game_type_ranks`.`user_id` = 1 AND `game_type_ranks`.`game_type_id` = 1 LI                                                                             MIT 1
  SQL (0.6ms)  INSERT INTO `game_type_ranks` (`created_at`, `game_type_id`, `ran                                                                             k`, `total_points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 1, 1                                                                             , 20, '2013-03-06 02:22:16', 1)
  GameTypeRank Load (0.5ms)  SELECT `game_type_ranks`.* FROM `game_type_ranks` W                                                                             HERE `game_type_ranks`.`user_id` = 2 AND `game_type_ranks`.`game_type_id` = 1 LI                                                                             MIT 1
  SQL (0.5ms)  INSERT INTO `game_type_ranks` (`created_at`, `game_type_id`, `ran                                                                             k`, `total_points`, `updated_at`, `user_id`) VALUES ('2013-03-06 02:22:16', 1, 2                                                                             , 75, '2013-03-06 02:22:16', 2)
   (7.4ms)  COMMIT
=> nil