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databaseconcurrency

Is a strict schedule always serializable?


In DBMS, is a strict schedule always serializable?

If the answer is no, then please provide an example of a strict schedule which is not serializable.


Solution

  • Every serializable schedule is strict. But every strict schedule is not serializable.

    Schedules heirarchy

    A Schedule is a serializable schedule if its outcome is equal to the outcome of its transactions executed serially i.e. without interleaving the transactions.

    Whereas, a strict schedule is the one in which some other transaction T2 cannot read or write the data written by T1 unless it is committed.

    So for example,Strict schedule which is not serializable

    In other words in Strict schedule T2 can read the data which is being read by T1, but once T1 writes the data, from that time to the time it commits, T2 cannot read or write the data.