Before a block of data in main memory can be output to the database, all log records pertaining to data in that block must have been output to stable storage. This is

DBMS - RECOVERY SYSTEM MCQ

• The log is a sequence of ___________, recording all the update activities in the database
• In the ___________ scheme, a transaction that wants to update the database first creates a complete copy of the database
• The ____________ scheme uses a page table containing pointers to all pages; the page table itself and all updated pages are copied to a new location
• The current copy of the database is identified by a pointer, called _____________, which is stored on disk
• If a transaction does not modify the database until it has committed, it is said to use the ___________ technique
• If database modifications occur while the transaction is still active, the transaction is said to use the ___________technique
• ____________ using a log record sets the data item specified in the log record to the old value
• In the __________ phase, the system replays updates of all transactions by scanning the log forward from the last checkpoint
• The actions which are played in the order while recording it is called ______________ history
• A special redo-only log record is written to the log, where V1 is the value being restored to data item Xj during the rollback. These log records are sometimes called
• Which of the following is not a recovery technique?
• Checkpoints are a part of
• deals with soft errors, such as power failures
• Rollback of transactions is normally used to :
• A transaction performs on the isolation level of the Read Uncommitted if :
• Which commands are used to control which users have which privilege over which objects ?
• When a deadlock is detected the recovery is normally accomplished by :
• Which is not a desirable property of a transaction ?
• A directed graph which represents the deadlock is called :
• Transaction Throughput is :
• Data encryption techniques are particularly useful for
• Before any changes to database structure are attempted one should first:
• Which of the following modifications may not succeed?
• Because of the importance of making data model changes correctly, many professionals are ________ about using an automated process for database redesign
• Which of the following can cause a transaction failure
• If the transaction can no longer continue with its normal execution because of some internal condition, it is called as a _________
• If a system has entered and undesirable state due to which it is unable to continue with normal execution, it is called as _________
• If there is a hardware malfunction or a bug in the database that causes the loss of content of volatile storage, it is called as ________
• The assumption that the hardware errors bring the system to a halt is called as ________
• Which of the following is not a classification of storage
• If a failure has occurred in the midst of a transfer, it is called as _________
• State true or false: The destination block has incorrect information in case of a total failure
• The partitions of the database into fixed length storage units are called as __________
• The blocks residing on the disk are referred to as ___________
• The area of memory where blocks temporarily reside is called as ________
• The most widely used structure for recording database modification is called as _______
• An update log record describes a ________ database write
• Which of the following fields does the update log record have?
• The unique identifier of the transaction that performed the write operation is called as _______
• The value of the data item prior to the write is called as _________
• If a transaction does not modify the database until it has committed it is said to use a _______ modification technique
• We say that a transaction has been ________ when its commit log record has been output to stable storage
• State true or false: Using checkpoints reduces overhead
• A __________ checkpoint is a checkpoint where transactions are allowed to perform updates even while buffer blocks are being written out
• If the database modifications occur while the transaction is still active, the transaction is said to use the __________ modification technique
• The log is a sequence of _________ recording all the update activities in the database
• The current copy of the database is identified by a pointer, called ____________ which is stored on disk
• A special redo-only log record <Ti , Xj , V1> is written to the log, where V1 is the value being restored to data item Xj during the rollback. These log records are sometimes called
• In order to reduce the overhead in retrieving the records from the storage space we use
• The order of log records in the stable storage ____________ as the order in which they were written to the log buffer
• Before a block of data in main memory can be output to the database, all log records pertaining to data in that block must have been output to stable storage. This is
• Writing the buffered log to __________ is sometimes referred to as a log force
• The _______________ policy, allows a transaction to commit even if it has modified some blocks that have not yet been written back to disk
• ______________ policy allows multiple updates to accumulate on a block before it is output to stable storage, which can reduce the number of output operations greatly for frequently updated blocks
• The ___________ policy, allows the system to write modified blocks to disk even if the transactions thatmade those modifications have not all committed
• Locks on buffer blocks are unrelated to locks used for concurrency-control of transactions, and releasing them in a non-two-phase manner does not have any implications on transaction serializability. This is
• The __________________ contains a list of blocks that have been updated in the database buffer
• The operating system reserves space on disk for storing virtual-memory pages that are not currently in main memory; this space is called
• What was the name of the first commercially available microprocessor chip?
• The magnetic storage chip used to provide non-volatile direct access storage of data and that have no moving parts are known as
• Which of the following is used only for data entry and storage, and never for processing?
• Non-volatile storage needs to have a _________ where the loses in future can be recovered
• A dump of the database contents is also referred to as an _____________ dump
• ________ dump, writes out SQL DDL statements and SQL insert statements to a file, which can then be reexecuted to re-create the database
• _________ dump schemes have been developed that allow transactions to be active while the dump is in progress
• ARIES uses a ___________ to identify log records, and stores it in database pages
• ARIES supports ___________ operations, which are physical in that the affected page is physically identified, but can be logical within the page
• ______________ is used to minimize unnecessary redos during recovery
• __________ scheme that records only information about dirty pages and associated information and does not even require of writing dirty pages to disk
• Whenever an update operation occurs on a page, the operation stores the LSN of its log record in the _______ field of the page
• There are special redo-only log records generated during transaction rollback, called _________ in ARIES
• The __________________ contains a list of pages that have been updated in the database buffer
• ___________ determines which transactions to undo,which pages were dirty at the time of the crash, and the LSN from which the redo pass should start
• __________ starts from a position determined during analysis, and performs a redo, repeating history, to bring the database to a state it was in before the crash
• ______________ rolls back all transactions that were incomplete at the time of crash
• Which lock should be obtained to prevent a concurrent transaction from executing a conflicting read, insert or delete operation on the same key value
• The remote backup site is sometimes also called the
• Remote backup system must be _________ with the primary site
• The backup is taken by
• When the __________ the backup site takes over processing and becomes the primary
• The simplest way of transferring control is for the old primary to receive __________ from the old backup site
• The time to process the remote backup can be reduced by
• A _______________ configuration can make takeover by the backup site almost instantaneous
• A transaction commits as soon as its commit log record is written to stable storage at the primary site. This is
• A transaction commits as soon as its commit log record is written to stable storage at the primary and the backup site.This is
• If only the primary is active, the transaction is allowed to commit as soon as its commit log record is written to stable storage at the primary site. This is
• Once the lower-level lock is released, the operation cannot be undone by using the old values of updated data items, and must instead be undone by executing a compensating operation; such an operation is called
• Which of the following is used for undo operations alone ?
• Redo operations are performed exclusively using
• To perform logical redo or undo, the database state on disk must be operation ___________ that is, it should not have partial effects of any operation
• An operation is said to be __________ if executing it several times in a row gives the same result as executing it once
• Immediate database modification technique uses
• Shadow paging has
• For correct behavior during recovery, undo and redo operation must be
• If ___________ are not obtained in undo operation it will cause problem in undo-phase

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