Question

Consider the following database schedule with two transactions, T₁ and T₂.

S = r₂(X); r₁(X); r₂(Y); w₁(X); r₁(Y); w₂(X); a₁; a₂ 

where r_i(Z) denotes a read operation by transaction T; on a variable Z, w_i;(Z) denotes a write operation by T_i on a variable Z and a, denotes an abort by transaction T_i.

Which one of the following statements about the above schedule is TRUE?

(A) S is non-recoverable 

(B) S is recoverable, but has a cascading abort 

(C) S does not have a cascading abort 

(D) S is strict

Answer 1

(C) S does not have a cascading abort 

No transaction is reading the data item written by some other transaction. So the given schedule is cascade less.