What are costs to be considere when transaction is roll back, Database Management System

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What are the costs to be considered when a transaction has to be rolled back when recovering from deadlock?       

 Ans: A few transaction will must rolled back (made a victim) to break deadlock.

Choose that transaction as victim which will incur minimum cost. 

  • Rollback - find out how far to roll back transaction.
  • Total rollback: Abort the transaction and after that restart it.
  • More efficient to roll back transaction only as far as essential to break deadlock.
  • Starvation occurs if same transaction is always selected as victim. Include the number of rollbacks in the cost factor to prevent starvation.

 


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