Consider aserial schedule which involves 3 data items A, B, C with initial value 1000, 2000, 800,

Consider aserial schedule <T ₀ ,T ₁ ,T ₂ > which involves 3 data items A, B, C with initial value 1000, 2000, 800, respectively. Assuming the sytem has crashed, for any of the following log files, state the corresponding recovery plan (i.e list the transactions needed to be undone and redone in order and for each transacton T, state the values of the data items that are involved in the transaction T after the undone and redone operation)

a. <T ₀ ,start>, <T ₀ , A, 1000, 900>, <T ₀ , B, 2000, 2100>

b. <T ₀ , start>, < T ₀ , A, 100, 900>, <T ₀ , B, 2000, 2100>, <T _0, commit>, < T ₁ , start>, <T ₁ , C, 800, 900>

c. <T ₀ , start>, <T ₀ , A, 1000, 900>, < T _0, B, 2000, 2100>, <T ₀ , commit>, <T ₁ , start>, <T ₁ , C, 800, 900>, <T _1, commit>, <T ₂ , C, 900, 1000>

d. <T ₀ , start>, <T ₀ , A, 900>, <T ₀ , B, 2100>

e. <T ₀ , start>, < T ₀ , A, 900>, <T ₀ , B, 2100>, <T ₀ , commit>, <T ₁ , start>, <T ₁ , C, 900>, <T ₁ , commit>, <T ₂ , C, 900,1000>

Answer rating: 100% (QA)

a Since T0 has not committed yet and the system crashed So Undo T0 needs to be done since is present ... View the full answer