If a database crashes before a transaction can complete, what's the best way to recover your database?
- Reprocess transactions
- Switch to a duplicate database
- Rollback
- Rollforward
EXPLANATION
When more than one transaction are being executed in parallel, the logs are interleaved. At the time of recovery, it would become hard for the recovery system to backtrack all logs, and then start recovering.
Undo or transaction backout recovery is performed by the DBMS Server. For example, when a transaction is aborted, transaction log file information is used to roll back all related updates. ... A Redo recovery operation is database-oriented. Redo recovery is performed after a server or an installation fails.
Crash recovery is the process by which the database is moved back to a consistent and usable state. This is done by rolling back incomplete transactions and completing committed transactions that were still in memory when the crash occurred
Crash recovery is the process by which the database is moved back to a consistent and usable state. This is done by rolling back incomplete transactions and completing committed transactions that were still in memory when the crash occurred
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