Database Recovery
Database recovery techniques are crucial in ensuring the integrity and permanence of data in response to various failures. The chapter categorizes failures into transaction failures, system crashes, and disk failures, each requiring specific recovery strategies. Emphasis is placed on log-based recovery mechanisms, checkpoints, shadow paging, and media recovery to maintain the ACID properties of transactions.
Sections
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What we have learnt
- Database recovery is essential for maintaining data integrity after failures.
- Types of failures include transaction failures, system crashes, and disk failures.
- Log-based recovery, checkpoints, and shadow paging are key techniques for database recovery.
Key Concepts
- -- Transaction Failure
- A condition where a transaction cannot complete successfully due to logic errors, internal database errors, or user-initiated aborts.
- -- LogBased Recovery
- A recovery technique that uses a sequential log of all changes to undo or redo transactions after a failure.
- -- Checkpoints
- Mechanisms that periodically synchronize the in-memory state of the database with its disk state, reducing recovery time.
- -- Shadow Paging
- A recovery technique using two page tables to maintain a consistent database state without detailed logging.
- -- Media Recovery
- The process of restoring a database after the loss of primary data files due to hardware failures.
Additional Learning Materials
Supplementary resources to enhance your learning experience.