Recoverability and Irrecoverability of Schedules in Database Management

In the system crash, non-volatile storage is assumed not to be corrupted.

Disk failure occurs due to the formation of bad sectors, disk head crash, and unreachability to the disk.

Log-based recovery involves maintaining a sequence of transaction records in stable storage to recover from failures.

<p>Deferred modification technique delays updating the database until a transaction has committed.</p> Signup and view all the answers

<p>A recoverable schedule can be undone if needed, while an irrevocable schedule cannot be rolled back.</p> Signup and view all the answers

<p>A serial schedule is where one transaction is executed completely before starting another transaction.</p> Signup and view all the answers

<p>A serial schedule executes transactions one after the other with no interleaving, while a non-serial schedule allows interleaving of operations.</p> Signup and view all the answers

<p>After aborting a transaction, the database recovery module can either re-start the transaction or kill the transaction.</p> Signup and view all the answers

<p>A schedule is a series of operations from one transaction to another, used to preserve the order of operations within each transaction.</p> Signup and view all the answers

<p>Serializability helps in finding non-serial schedules that allow transactions to execute concurrently without interfering with each other.</p> Signup and view all the answers

<p>A serializable schedule ensures that even if transactions execute concurrently, the end result is equivalent to some serial execution of those transactions.</p> Signup and view all the answers

<p>Serializability in transaction schedules ensures that the result of a non-serial schedule is equal to the result of its transactions executed serially.</p> Signup and view all the answers

<p>A precedence graph is used to test the serializability of a schedule by representing the order of operations between transactions.</p> Signup and view all the answers

<p>A schedule is conflict serializable if it can be transformed into a serial schedule by swapping nonconflicting operations.</p> Signup and view all the answers

<p>Two operations are conflicting if they belong to separate transactions and involve the same data item.</p> Signup and view all the answers

<p>Testing serializability ensures that concurrent transactions maintain consistency and do not lead to data corruption.</p> Signup and view all the answers

<p>The precedence graph helps visualize the order of operations and potential conflicts between transactions in a schedule.</p> Signup and view all the answers

<p>Two schedules are said to be conflict equivalent if they contain the same set of transactions and if each pair of conflict operations are ordered in the same way.</p> Signup and view all the answers

<p>A serial schedule ensures that all operations of one transaction are performed before starting any operation of another transaction.</p> Signup and view all the answers

<p>A schedule can be transformed into a serial schedule by ensuring that all operations of one transaction are performed before any operation of another transaction.</p> Signup and view all the answers

<p>Conflict serializability refers to the property of a schedule that can be transformed into a serial schedule by swapping non-conflicting operations.</p> Signup and view all the answers

<p>Swapping non-conflicting operations allows schedules to be transformed into conflict equivalent schedules without affecting the final result.</p> Signup and view all the answers

<p>Two schedules are considered conflict equivalent if they contain the same set of transactions and if each pair of conflict operations are ordered in the same way.</p> Signup and view all the answers