19 Questions
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?
Precedence graphs are used to illustrate the order of operations between transactions.
What criterion determines the creation of an edge Ti -> Tj in a precedence graph?
The edge Ti -> Tj is created when Ti writes to a data item before Tj reads from it.
What is the significance of a schedule being serializable?
A serializable schedule ensures that the result is the same as if the transactions were executed in a serial manner.
When does a precedence graph contain a single edge Ti -> Tj?
If all instructions of Ti are executed before the first instruction of Tj in the schedule.
Define conflict equivalent schedules.
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.
What is a serial schedule?
A serial schedule is a schedule in which all operations of one transaction are performed before starting any operation of another transaction.
How can a schedule be transformed into a serial schedule?
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.
What is the condition for two schedules to be conflict equivalent?
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.
Explain the concept of conflict serializability.
Conflict serializability refers to the property of a schedule being equivalent to a serial schedule after swapping non-conflicting operations.
What are the two possible outcomes in a serial schedule when there is no interleaving of operations?
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.
What is a serial schedule?
A type of schedule where one transaction is executed completely before starting another transaction.
In what scenario would two schedules be considered non-conflict equivalent?
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.
Define non-serial schedule.
A schedule where interleaving of operations is allowed, resulting in many possible orders in which the system can execute individual operations of the transactions.
What happens after aborting a transaction in terms of database recovery?
The database recovery module will select one of the two operations: re-start the transaction or kill the transaction.
Explain the concept of transaction scheduling.
Transaction scheduling involves arranging a series of operations from one transaction to another to ensure proper execution order.
What is the purpose of serializability in schedules?
To find non-serial schedules that allow transactions to execute concurrently without interfering with one another.
Test your knowledge on database recovery and transaction scheduling concepts including serial schedules. Learn about different types of schedules and the process of recovering a database post transaction abort.
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