base.rb

csv.drop(params[:is_column_headings].present? || params[:matched_columns].nil? ? 1 : 0).each_slice(500) do |rows|
          ActiveRecord::Base.transaction do  # Make sure all record persistance is rolled back if an exception occurs
            rows.each do |row|
              # load data
              columns.values.each_with_index{|named_columns, i| data.merge!(named_columns => row[i]) if named_columns}
              # build record
              if duplicate_record?(is_skip_duplicates, data, current_user)
                row << "This record is potentialy a duplicate and was not #{self.name.split("::")[1].downcase}ed."
                status = "errors"
              else
                status, row = build_record(row, data, current_user, additional_details)
              end
              results[status.to_sym] << row
            end
          end
        end