If space, use it, else put new record in an overflow block . Adjust pointers accordingly. Figure 10.16 shows the previous example after an insertion. If very few records in overflow blocks, this will work well. If order is lost, reorganize the file.
Reorganizations are expensive and done when system load is low.
If insertions rarely occur, we could keep the file in physically sorted order and reorganize when insertion occurs. In this case, the pointer fields are no longer required.