return if limit_columns.empty?
model_class.transaction do
limit_query = @objects.
+ except(:select).
select("(%s) as read_length" %
- limit_columns.map { |s| "length(#{s})" }.join(" + "))
+ limit_columns.map { |s| "octet_length(#{s})" }.join(" + "))
new_limit = 0
read_total = 0
limit_query.find_each do |record|