The main goal of recovery is to ensure the atomicity property of a transaction. If a transaction fails before completing its execution, the recovery mechanism has to make sure that the transaction has no lasting effects on the database. The different approaches to recovery : – Deferred Update : These techniques postpone any actual updating [...]
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Shadow paging is an alternative to log-based recovery techniques, which has both advantages and disadvantages. It may require fewer disk accesses, but it is hard to extend paging to allow multiple concurrent transactions. The paging is very similar to paging schemes used by the operating system for memory management. How Shadow Paging is performed ? [...] A computer system, like any other mechanical or electrical system is subject to failure. There are a variety of causes, including disk crash, power failure, software errors, a fire in the machine room, or even sabotage. Whatever the cause, information may be lost. The database must take actions in advance to ensure that the atomicity [...] |
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