フリー問題

問題文

A long batch inserts rows in three phases and the operator wants to be able to undo only the third phase. Which statement about save points is correct?

選択肢

1. A save point holds a position inside the transaction so the later work is written to a separate segment and can be applied again later.
2. A save point commits the work done so far so a rollback to that mark undoes the later work and leaves the earlier work already confirmed.
3. A save point marks a position inside the transaction so a rollback to that mark undoes the later work and leaves the earlier work still pending.
4. A save point names a position inside the transaction so a rollback to that mark undoes the whole transaction and releases every lock it holds.