Q. An update log record describes a ________ database write

View solution

Q. Which of the following fields does the update log record have?

View solution

Q. The unique identifier of the transaction that performed the write operation is called as _______

View solution

Q. The value of the data item prior to the write is called as _________

View solution

Q. If a transaction does not modify the database until it has committed it is said to use a _______ modification technique

View solution

Q. We say that a transaction has been ________ when its commit log record has been output to stable storage.

View solution

Q. State true or false: Using checkpoints reduces overhead

View solution

Q. A __________ checkpoint is a checkpoint where transactions are allowed to perform updates even while buffer blocks are being written out.

View solution

Q. If the database modifications occur while the transaction is still active, the transaction is said to use the __________ modification technique

View solution

Q. The log is a sequence of _________ recording all the update activities in the database.

View solution

Q. The current copy of the database is identified by a pointer, called ____________ which is stored on disk.

View solution

Q. 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

View solution

Q. In order to reduce the overhead in retrieving the records from the storage space we use

View solution

Q. The order of log records in the stable storage ____________ as the order in which they were written to the log buffer.

View solution

Q. 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

View solution

Q. Writing the buffered log to __________ is sometimes referred to as a log force.

View solution

Q. The _______________ policy, allows a transaction to commit even if it has modified some blocks that have not yet been written back to disk.

View solution

Q. ______________ 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.

View solution

Q. The ___________ policy, allows the system to write modified blocks to disk even if the transactions thatmade those modifications have not all committed.

View solution

Q. 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

View solution