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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?
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- T2 must be aborted and then both T1 and T2 must be re – started to ensure transaction atomicity
- Schedule S is non – recoverable and cannot ensure transaction atomicity
- Only T2 must be aborted and then re – started to ensure transaction atomicity
- Schedule S is recoverable and can ensure atomicity and nothing else needs to be done
- T2 must be aborted and then both T1 and T2 must be re – started to ensure transaction atomicity
Correct Option: B
T2 is reading the value written by T1 and getting committed before T1 commits. So it is non-recoverable schedule.
