Questions from Database Systems

Q: Under what conditions is it less expensive to avoid deadlock than to

Under what conditions is it less expensive to avoid deadlock than to allow deadlocks to occur and then to detect them?

Q: If deadlock is avoided by deadlock-avoidance schemes, is starvation

If deadlock is avoided by deadlock-avoidance schemes, is starvation still possible? Explain your answer.

Q: In multiple-granularity locking, what is the difference between implicit

In multiple-granularity locking, what is the difference between implicit and explicit locking?

Q: Although SIX mode is useful in multiple-granularity locking, an

Although SIX mode is useful in multiple-granularity locking, an exclusive and intention-shared (XIS) mode is of no use. Why is it useless?

Q: Describe the differences in meaning between the terms relation and relation schema

Describe the differences in meaning between the terms relation and relation schema.

Q: The multiple-granularity protocol rules specify that a transaction Ti can

The multiple-granularity protocol rules specify that a transaction Ti can lock a node Q in S or IS mode only if Ti currently has the parent of Q locked in either IX or IS mode. Given that SIX and S lo...

Q: Suppose the lock hierarchy for a database consists of database, relations

Suppose the lock hierarchy for a database consists of database, relations, and tuples. a. If a transaction needs to read a lot of tuples from a relation r, what locks should it acquire? b. Now suppose...

Q: Explain the difference between the three storage types — volatile, nonvolatile

Explain the difference between the three storage types — volatile, nonvolatile, and stable— in terms of I/O cost.

Q: Consider the log in Figure 19.7. Suppose there is

Consider the log in Figure 19.7. Suppose there is a crash during recovery, just before the operation abort log record is written for operation O1. Explain what will happen when the system recovers aga...

Q: Compare log-based recovery with the shadow-copy scheme in

Compare log-based recovery with the shadow-copy scheme in terms of their overheads for the case when data are being added to newly allocated disk pages (in other words, there is no old value to be res...