Schedules

  • A Schedule indicate the chronological order in which instructions of concurrent transactions are executed.
  • a schedule for a set of transactions must consist of all instructions of those transactions.
  • must preserve the order in which the instructions appear in each individual transaction.
  1. Serial Schedule
    • After Termination of one transaction then begins other transaction.
    • All serial schedules are always consistent
    • Drawback: Throughput of the system is very less.
    • Example:! Let T1 transfer 50 from A to B, and T2 transfer 10% of the balance from A to B. The following is a serial schedule, in which T1 is followed by T2
  2. Concurrent Schedule
    • Simultaneous or interleaved execution of two or more transactions.
    • It can be either Consistent or Inconsistent.
    • Example: Below is a concurrent schedule but it is equivalent to serial schedule(Consistent Schedule)
    • Example: Below is a concurrent schedule but it is not equivalent to serial schedule(InConsistent Schedule)

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