Consider the log shown below.

LSN LOG

00 update: T1 writes P3

10 update: T1 writes P1

20 update: T1 writes P2

30 update: T2 writes P3

40 begin checkpoint

45 end checkpoint

50 update: T3 writes P4

60 T1 commit

70 update: T3 writes P2

80 T1 end

90 update: T2 writes P1

100 T2 commit CRASH, RESTART

In this log, we store information about 3 transactions. After the log record with LSN 100, the system crashes and then we restart. We use the ARIES recovery algorithm discussed in Chapter 18 in the book. Based on that, answer the following questions:

1. What is done during the Analysis phase?

2. What is done during the Redo phase?

3. What is done during the Undo phase?

4. Show the log when recovery is complete, including all non-null prevLSN and undonextLSN values in log records