1
GATE CSE 2015 Set 3
+2
-0.6
Consider the following partial Schedule S involving two transactions $$T1$$ and $$T2.$$ Only the read and the write operations have been shown. The read operation on data item $$P$$ is denoted by read$$(P)$$ and the write operation on data item $$P$$ is denoted by write $$(P).$$

Suppose that the transaction $$T1$$ fails immediately after time instance $$9.$$ Which one of the following statements is correct?

A
$$T2$$ must be aborted and then both $$T1$$ and $$T2$$ must be re-started to ensure transaction atomicity
B
Schedule $$S$$ is non-recoverable and cannot ensure transaction atomicity
C
Only $$T2$$ must be aborted and then re-started to ensure transaction atomicity
D
Schedule $$S$$ is recoverable and can ensure atomicity and nothing else needs to be done
2
GATE CSE 2014 Set 1
+2
-0.6
Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item x, denoted by r(x) and w(x) respectively. Which one of them is conflict serializable?
A
r1(x); r2(x); w1(x); r3(x); w2(x)
B
r2(x); r1(x); w2(x); r3(x); w1(x)
C
r3(x); r2(x); r1(x); w2(x); w1(x)
D
r2(x); w2(x); r3(x); r1(x); w1(x)
3
GATE CSE 2014 Set 3
+2
-0.6
Consider the transactions T1, T2, and T3 and the schedules S1 and S2 given below.

T1 : r1 (X) ; r1 (Z) ; w1 (X) ; w1 (Z)

T2 : r2 (X) ; r2 (Z) ; w2 (Z)

T3 : r3 (X) ; r3 (X) ; w3 (Y)

S1: r1(X); r3(Y); r3(X); r2(Y); r2(Z); w3(Y); w2(Z); r1(Z); w1(X); w1(Z)

S2: r1(X); r3(Y); r2(Y); r3(X); r1(Z); r2(Z); w3(Y); w1(X); w2(Z); w1(Z)

Which one of the following statements about the schedules is TRUE?
A
Only S1 is conflict-serializable.
B
Only S2 is conflict-serializable.
C
Both S1 and S2 are conflict-serializable.
D
Neither S1 nor S2 is conflict-serializable.
4
GATE CSE 2014 Set 2
+2
-0.6
Consider the following schedule S of transactions T1, T2, T3, T4:
A
S is conflict-serializable but not recoverable
B
S is not conflict-serializable but is recoverable
C
S is both conflict-serializable and recoverable
D
S is neither conflict-serializable not is it recoverable
GATE CSE Subjects
EXAM MAP
Medical
NEET