1Z0-082 - Oracle Database Administration I Managing Undo Data Questions and Answers

Question 1

A long-running report fails with an ORA-01555 "snapshot too old" error. What is the most likely cause?

Accepted Answer

The UNDO_RETENTION period is shorter than the query's execution time, causing necessary undo data to be overwritten.

Answer

The temporary tablespace ran out of space during a sort operation.

Answer

The user running the report lacks the necessary SELECT privileges on the underlying tables.

Answer

The database instance was restarted while the query was executing.

Question 2

Which initialization parameter must be set to 'AUTO' to enable Automatic Undo Management (AUM)?

Accepted Answer

UNDO_MANAGEMENT

Answer

TRANSACTION_CONTROL

Answer

ROLLBACK_SEGMENTS

Answer

UNDO_TABLESPACE

Question 3

A database administrator needs to ensure that unexpired undo data is never overwritten, even if it means subsequent DML operations that require undo space will fail. Which action accomplishes this?

Accepted Answer

Enable `RETENTION GUARANTEE` on the active undo tablespace.

Answer

Set the UNDO_RETENTION parameter to a very high value.

Answer

Create the undo tablespace with the `AUTOEXTEND ON MAXSIZE UNLIMITED` clause.

Answer

Set the `UNDO_MANAGEMENT` parameter to `GUARANTEE`.

Question 4

Which of the following are the three primary purposes of undo data in an Oracle database?

Accepted Answer

Transaction rollback, read consistency, and instance recovery.

Answer

Archiving redo logs, managing password policies, and storing PL/SQL code.

Answer

Performing checkpoints, writing dirty buffers to disk, and managing the shared pool.

Answer

Auditing user activity, enforcing resource limits, and caching data dictionary information.

Question 5

A DBA needs to analyze historical undo generation rates and identify the longest-running queries over the past few days to properly size the undo tablespace. Which dynamic performance view is best suited for this task?

Accepted Answer

V$UNDOSTAT

Answer

V$TRANSACTION

Answer

V$SESSION_LONGOPS

Answer

DBA_UNDO_EXTENTS

Question 6

When using Automatic Undo Management (AUM), what happens if the instance starts and the undo tablespace specified in the `UNDO_TABLESPACE` parameter is not available?

Accepted Answer

The instance will start without an undo tablespace and use the SYSTEM tablespace for undo records.

Answer

The instance will fail to start and report an ORA-01092 error.

Answer

The instance will automatically create a new undo tablespace with a default name.

Answer

The instance will start in restricted mode, allowing only DBA connections.

A long-running report fails with an ORA-01555 "snapshot too old" error.What is the most likely cause?

A long-running report fails with an ORA-01555 "snapshot too old" error.
What is the most likely cause?