Consider the following concurrent execution of transactions T1, T2 and T3:

 

 

R1(A) R1(C) W1(A) R2(B) W1(C) R2(A) R3(C) W2(B) R3(B) W3(C) W2(A) W3(B)

 

 

1. Is the schedule serializable? Draw a precedence graph and justify your answer. If serializable, what is the serializability order? If serializable, give an equivalent serial schedule.

 

 

 

 

 

 

 

1. Is this schedule allowed under 2PL?

Is this schedule allowed under 2PL with isolation?

Attempt to add lock and unlock instructions to the transactions and justify your answer.

 

 

	1	2	3	4	5	6	7	8	9	10	11	12
Schedule

 

 

1. Is this schedule allowed under the basic timestamp protocol?
   
    

Show a trace of the timestamp algorithm to justify your answer.

 

 

	1	2	3	4	5	6	7	8	9	10	11	12
Schedule
MRT(A)
MWT(A)
MRT(B)
MWT(B)
MRT(C)
MWT(C)