Sa: rl(x); r2(2); rl (2); 13(x); r3(y); w1(x); cl; w3(y); c3; 12(y); w2(z); w2(y);c2 is recoverable or not
The given schedule is not recoverable.
In order for a schedule to be recoverable, it must satisfy the recoverability criterion, which states that if a transaction T2 reads a data item previously written by another transaction T1, then the commit operation of T1 must appear before the commit operation of T2 in the schedule.
However, in the given schedule, transaction T2 reads the value of y that was written by T3 before T1 commits. Therefore, the schedule violates the recoverability criterion and is not recoverable.