Advanced Database System - Transaction and Recovery

These flashcards cover key vocabulary and concepts within database transaction management to help understand recovery mechanisms, concurrency control, and data integrity.

Backup facilities

Mechanisms that provide back-up copies of portions of or the entire database.

Cold back-up

A full back-up of a database where all data is stored.

Hot back-up

A back-up where only a selected portion of the database is taken offline.

Journalizing facilities

Maintain an audit trail of transactions and changes made to the database.

Checkpoint facility

A process by which the DBMS synchronizes files and journals to establish a recovery point.

Recovery manager

Allows the DBMS to restore the database to a correct condition after a failure.

Disk Mirroring

Keeping at least two copies of the database updated simultaneously to switch processing in case of a media failure.

Rollback

The process of undoing unwanted changes to the database.

Rollforward

A technique that moves a database forward using after-images of good transactions.

ACID properties

Four properties that ensure that database transactions are processed reliably: Atomicity, Consistency, Isolation, and Durability.

Deadlock

An impasse that results when two or more transactions have locked a common resource and each waits for the other to unlock it.

Two-phase locking protocol

A procedure for acquiring necessary locks for transactions where all needed locks are obtained before any are released.

Versioning

A concurrency control method where no locking is used, and each transaction sees a snapshot of the database at its start.

Data Dictionary

A repository of information that documents data elements of a database.

Active data dictionary

A data dictionary managed automatically by the database management software.

Passive data dictionary

A data dictionary managed manually by users and modified when changes occur in the database structure.

Information Repository Dictionary System (IRDS)

Software tool for managing and controlling access to an information repository.

Isolation

A property ensuring that changes made by a transaction are not visible to other transactions until the transaction is committed.

Serialized Schedule

A transaction processing schedule ensuring the same result as if transactions were executed one after the other.

Cascading Abort

A situation where aborting one transaction leads to the necessity of aborting others that depended on it.

Unrecoverable Schedule

A schedule in which a transaction that reads data written by an aborted transaction should also be aborted.