instance method hash_rows

# File activerecord/lib/active_record/result.rb, line 141
      def hash_rows
        @hash_rows ||=
          begin
            # We freeze the strings to prevent them getting duped when
            # used as keys in ActiveRecord::Base's @attributes hash
            columns = @columns.map(&:-@)
            length  = columns.length

            @rows.map { |row|
              # In the past we used Hash[columns.zip(row)]
              #  though elegant, the verbose way is much more efficient
              #  both time and memory wise cause it avoids a big array allocation
              #  this method is called a lot and needs to be micro optimised
              hash = {}

              index = 0
              while index < length
                hash[columns[index]] = row[index]
                index += 1
              end

              hash
            }
          end
      end