1. Table 5 shows the airline’s transaction log file. Suppose that part of the airline’s computer system fails at 15:06. Assume that the DBMS is using the Immediate Update protocol.

1. Describe the actions that the recovery manager would take to recover from the failure. Explain why each action is taken.

2. Describe how the recovery manager would use the recovery log during the recovery from the failure. State the order in which it would do things.

Transaction	Data items locked by transaction	Data items transaction is waiting to lock
T1		C
T2	B, C	E
T3	A, E
T4	D	A
T5		A, B, D

Table 4: Information on locks.

Transaction ID	Time	Operation	Seat	Before Image	After Image
T1	14:40	Start
T1	14:41	Delete	S1	Kahn
T2	14:43	Start
T2	14:44	Delete	S16
T2	14:46	Update	S3	Smith	Patel
T3	14:48	Start
T1	14:49	Update	S5	Jones	Wu
T1	14:51	Commit
T2	14:52	Insert	S9		McKay
T3	14:55	Delete	S18	Dixon
T2	14:57	Commit
	14:58	Checkpoint
T4	14:59	Start
T3	15:01	Commit
T4	15:05	Update	S9	Green	Ali

Table 5: Recovery Log File