Database Recovery and Transaction Scheduling Quiz
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Questions and Answers

What is the purpose of the Serialization Graph in testing the Serializability of a schedule?

To test if a schedule is conflict serializable.

When is a schedule considered conflict serializable?

A schedule is conflict serializable if it can transform into a serial schedule after swapping nonconflicting operations.

What conditions make two operations conflicting in a schedule?

Both operations belong to separate transactions and involve the same data item.

How are precedence graphs used in testing the Serializability of a schedule?

<p>Precedence graphs are used to illustrate the order of operations between transactions.</p> Signup and view all the answers

What criterion determines the creation of an edge Ti -> Tj in a precedence graph?

<p>The edge Ti -&gt; Tj is created when Ti writes to a data item before Tj reads from it.</p> Signup and view all the answers

What is the significance of a schedule being serializable?

<p>A serializable schedule ensures that the result is the same as if the transactions were executed in a serial manner.</p> Signup and view all the answers

When does a precedence graph contain a single edge Ti -> Tj?

<p>If all instructions of Ti are executed before the first instruction of Tj in the schedule.</p> Signup and view all the answers

Define conflict equivalent schedules.

<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

What is a serial schedule?

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

How can a schedule be transformed into a serial schedule?

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

What is the condition for two schedules to be conflict equivalent?

<p>Two schedules are 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

Explain the concept of conflict serializability.

<p>Conflict serializability refers to the property of a schedule being equivalent to a serial schedule after swapping non-conflicting operations.</p> Signup and view all the answers

What are the two possible outcomes in a serial schedule when there is no interleaving of operations?

<p>Execute all the operations of T1 followed by all the operations of T2 OR execute all the operations of T2 followed by all the operations of T1.</p> Signup and view all the answers

What is a serial schedule?

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

In what scenario would two schedules be considered non-conflict equivalent?

<p>Two schedules are non-conflict equivalent if they do not contain the same set of transactions or if the order of conflict operations is not the same.</p> Signup and view all the answers

Define non-serial schedule.

<p>A schedule where interleaving of operations is allowed, resulting in many possible orders in which the system can execute individual operations of the transactions.</p> Signup and view all the answers

What happens after aborting a transaction in terms of database recovery?

<p>The database recovery module will select one of the two operations: re-start the transaction or kill the transaction.</p> Signup and view all the answers

Explain the concept of transaction scheduling.

<p>Transaction scheduling involves arranging a series of operations from one transaction to another to ensure proper execution order.</p> Signup and view all the answers

What is the purpose of serializability in schedules?

<p>To find non-serial schedules that allow transactions to execute concurrently without interfering with one another.</p> Signup and view all the answers

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