(Solved) : Consider Following Four Transactions Transaction T1 Readitem Readitem D Writeitem D Transa Q27986249 . . . .

Consider the following four transactions:

*Transaction T1: read_item(A); read_item(D); write_item(D);

*Transaction T2: read_item(B); write_item(B); read_item(D);write_item(D);

*Transaction T3: read_item(C); write_item(C);

*Transaction T4: read_item(D); write_item(D); read_item(A);write_item(A);

Following is a log corresponding to a particularschedule at the point of a system crash.

[start_transaction, T1]

[read_item, T1, A]

[read_item, T1, D]

[write_item, T1, D, 20, 25]

[commit, T1]

[checkpoint]

[start_transaction,T2]   

[read_item, T2, B]

[write_item, T2, B, 12, 18]

[start_transaction, T4]

[read_item, T4, D]

[write_item, T4, D, 15, 25]

[start_transaction, T3]

[write_item, T3, C, 30, 40]

[read_item, T4, A]

[write_item, T4, A, 30, 20]

[commit, T4]

[read_item, T2, D]

[write_item, T2, D, 15, 25]<-System Crash

Suppose