OCA-11-Managing Data Concurrency and Undo

A. DBWR flushes the changes to disk.

B. You issue a SAVEPOINT statement.

C. You issue a COMMIT statement.

D. A checkpoint occurs.

A. ALTER SYSTEM

B. SET ROLE

C. ALTER USER

D. None of the above

A. A tablespace

B. A table

C. The database

D. A transaction

E. The instance

A. ROW SHARE

B. ROW EXCLUSIVE

C. SHARE ROW EXCLUSIVE

D. All of the above

A. Undo tablespaces will not be created if they are not specified in the CREATE
DATABASE command.

B. Two undo tablespaces can be active if a new undo tablespace was specified and the
old one contains pending transactions.

C. You can switch from one undo tablespace to another while the database is online.

D. UNDO_MANAGEMENT cannot be changed dynamically while the instance is running.

A. Oracle automatically resolves the lock after a short but predefined time period by
killing the session that is holding the lock.

B. The DBA can kill the session holding the lock.

C. The user can either roll back or commit the transaction that is holding the lock.

D. Oracle automatically resolves the lock after a short but predefined period by killing
the session that is requesting the lock.

A. A new extent is allocated in the undo segment if all existing extents still contain
active transaction data.

B. Other transactions using the segment are moved to another existing segment with
enough free space.

C. A new undo segment is created, and the transaction that filled up the undo segment
is moved in its entirety to another undo segment.

D. The first extent in the segment is reused if the undo data in the first extent is
not needed.

E. The transaction that filled up the undo segment spills over to another undo segment.

A. LOCK TABLE HR.EMPLOYEES IN EXCLUSIVE MODE WAIT DEFERRED;

B. LOCK TABLE HR.EMPLOYEES IN SHARE MODE NOWAIT;

C. LOCK TABLE HR.EMPLOYEES IN SHARE MODE WAIT DISABLED;

D. LOCK TABLE HR.EMPLOYEES IN EXCLUSIVE MODE NOWAIT DEFERRED;

A. Uncommitted undo information

B. Undo information required in case an instance crash requires a roll forward
operation when the instance is restarted

C. Committed undo information required to satisfy the undo retention interval

D. Expired undo information that is no longer needed to support a running transaction

A. SYSTEM

B. The user who initiated the transaction

C. SYS

D. The user who owns the object changed by the transaction

A. The value of the parameter UNDO_RETENTION

B. The number of Snapshot too old errors

C. The current size of the undo tablespace

D. The desired amount of time to retain undo data

E. The most recent undo generation rate

A. When session 1 has a table locked using the LOCK TABLE...EXCLUSIVE MODE statement,
all DML statements and queries wait until session 1 does a COMMIT or ROLLBACK .

B. When SELECT...FOR UPDATE is performed, the table is locked.

C. The DDL_LOCK_TIMEOUT parameter can be set to TRUE to not return the
ORA-00054 error.

D. The LOCK TABLE statement can include the WAIT clause to specify the number of
seconds to wait for acquiring the lock.

A. Readers block writers.

B. Writers block readers.

C. Readers block writers.

D. Writers do not block readers.

A. An INSERT statement reading from a global temporary table into a persistent table

B. An INSERT statement reading from a persistent table into a global temporary table

C. Roll back an UPDATE operation

D. Writing undo records during a DML operation

A. Tell Maria to rerun the query.

B. Increase Undo Retention.

C. The materialized view used in the query is stale and needs to be refreshed.

D. Increase the undo tablespace size.

A. Multiple active transactions can write concurrently to the same extent in an
undo segment.

B. Multiple active transactions can write concurrently to the same undo segment.

C. Each transaction acquires an extent in the undo segment and does not share
the extent.

D. Each transaction acquires a segment in the undo tablespace and does not share
the segments.

A. UPDATE

B. ALTER TABLE

C. ALTER SESSION

D. ALTER SYSTEM

A. A developer must lock the row before performing an update to prevent others from
changing the same row.

B. When a row in a table is locked, the table is locked and no other transactions can
update the table.

C. When two sessions try to update the same row at the same time, both sessions fail.

D. When a session tries to update the row already updated by another session, it waits
until the other session does a commit or rollback.