a) concurrent execution of transactions is equivalent to the transactions executed serially b) the transactions can be carried out one ...
View QuestionConsider a transaction T1 that committed prior to checkpoint. The <T1 commits> record appears in the log before the <checkpoint> record. Any modifications made by T1 must have been written to the stable storage either with the checkpoint or prior to it. Thus at recovery time ____________
Consider a transaction T1 that committed prior to checkpoint. The <T1 commits> record appears in the log before ...
View QuestionThe system periodically performs checkpoints that consists of the following operation(s) ____________
a) Putting all the log records currently in main memory onto stable storage b) putting all modified data ...
View QuestionThe undo and redo operations must be _________ to guarantee correct behaviour, even if a failure occurs during recovery process.
a) idempotent b) easy c) protected d) all of the mentioned Answer: a
View QuestionAn actual update is not allowed to a data item ____________
a) before the corresponding log record is written out to stable storage b) after the corresponding log record ...
View QuestionIn the write ahead logging a _____________ is maintained.
a) a memory b) a system c) a disk d) a log record Answer: d Explanation: a ...
View QuestionWrite ahead logging is a way ____________
a) to ensure atomicity b) to keep data consistent c) that records data on stable storage d) all of the ...
View QuestionThe state of the data accessed by an aborted transaction must be restored to what it was just before the transaction started executing. This restoration is known as ________ of transaction.
a) safety b) protection c) roll – back d) revert – back Answer: c Explanation: roll – back
View QuestionA terminated transaction that has completed its execution successfully is ____________ otherwise it is __________
a) committed, destroyed b) aborted, destroyed c) committed, aborted d) none of the mentioned Answer: c Explanation: A terminated transaction ...
View QuestionA collection of instructions that performs a single logical function is called ____________
a) transaction b) operation c) function d) all of the mentioned Answer: a Explanation: A collection of instructions that performs a ...
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