Exam 10: Transaction Management and Concurrency Control

The scheduler establishes the order in which the operations within concurrent transactions are executed.

Most multiuser ______________________________ automatically initiate and enforce locking procedures,where all locking information is managed by the lock manager.

A field-level lock allows concurrent transactions to access the same row,as long as they require the use of different fields within that row.

A growing phase in a two-phase lock is when a transaction acquires all the required locks without locking any data.

The multiuser DBMS must implement controls to ensure serializability and isolation of transactions,in addition to atomicity and durability,in order to guard the database's consistency and integrity.

In the optimistic approach,during the ____ phase,changes are permanently applied to the database.

In a page-level lock,the DBMS will lock an entire diskpage.

How does a shared/exclusive lock schema increase the lock manager's overhead?

A ____ lock allows concurrent transactions to access different rows of the same table.

Serializability means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.

The ANSI has defined standards that govern SQL database transactions.Transaction support is provided by two SQL statements: ____ and ROLLBACK.

Uniqueness ensures that no equal time stamp values can exist,and ____________________ ensures that time stamp values always increase.

The ____________________ rule states that only one transaction at a time can own an exclusive lock on the same object.

A(n)____ lock has only two stages (0 and 1).

Durability requires that all portions of the transaction must be treated as a single,logical unit of work in which all operations are applied and completed to produce a consistent database.

When using an optimistic approach,during the write phase,the transaction is validated to ensure that the changes made will not affect the integrity and consistency of the database.

As a rule,a(n)____________________ must unlock the object after its termination.

Database transaction ____________________ restores a database from an inconsistent state to a previously consistent state.

What are database checkpoints?

An optimistic approach is based on the assumption that the majority of the database operations do not conflict.