gistfile1.rb

# https://gist.github.com/sononum/6183139
module Kaminari
  module ActiveRecordRelationMethods
    def total_count_with_speed
      if where_values_hash.empty?
        sql = "SELECT (reltuples)::integer FROM pg_class r WHERE relkind = 'r' AND relname = #{self.connection.quote table_name}"
        @_hacked_total_count || (@_hacked_total_count = self.connection.execute(sql).first["reltuples"].to_i)
      else
        total_count_without_speed
      end
    end

    alias_method_chain :total_count, :speed
  end
end