1Z0-062 | A Review Of Actual 1Z0-062 practice test
Q1. Which action takes place when a file checkpoint occurs?
A. The checkpoint position is advanced in the checkpoint queue.
B. All buffers for a checkpointed file that were modified before a specific SCN are written to disk by DBWn and the SCN is stored in the control file.
C. The Database Writer process (DBWn) writes all dirty buffers in the buffer cache to data files.
D. The Log Writer process (LGWR) writes all redo entries in the log buffer to online redo log files.
Answer: C
Q2. You enabled an audit policy by issuing the following statements:
SQL> AUDIT POLICY ORA_DATABASE_PARAMETER BY SCOTT;
SQL> AUDIT POLICY ORA_DATABASE_PARAMETER BY SYS, SYSTEM;
For which database users and for which executions is the audit policy now active? Select two.
A. SYS, SYSTEM
B. SCOTT
C. Only for successful executions
D. Only for failed executions
E. Both successful and failed executions
Answer: A,E
Explanation: * The ORA_DATABASE_PARAMETER policy audits commonly used Oracle Database parameter settings. By default, this policy is not enabled.
Q3. Your multitenant container (CDB) containing three pluggable databases (PDBs) is running in ARCHIVELOG mode. You find that the SYSAUX tablespace is corrupted in the root container.
The steps to recover the tablespace are as follows:
1. Mount the CDB.
2. Close all the PDBs.
3. Open the database.
4. Apply the archive redo logs.
5. Restore the data file.
6. Take the SYSAUX tablespace offline.
7. Place the SYSAUX tablespace online.
8. Open all the PDBs with RESETLOGS.
9. Open the database with RESETLOGS.
10. Execute the command SHUTDOWN ABORT.
Which option identifies the correct sequence to recover the SYSAUX tablespace?
A. 6, 5, 4, 7
B. 10, 1, 2, 5, 8
C. 10, 1, 2, 5, 4, 9, 8
D. 10, 1, 5, 8, 10
Answer: A
Explanation: RMAN> ALTER TABLESPACE sysaux OFFLINE IMMEDIATE; RMAN> RESTORE TABLESPACE sysaux; RMAN> RECOVER TABLESPACE sysaux; RMAN> ALTER TABLESPACE sysaux ONLINE;
* Example:
While evaluating the 12c beta3 I was not able to do the recover while testing “all pdb files lost”.
Cannot close the pdb as the system datafile was missing…
So only option to recover was:
Shutdown cdb (10)
startup mount; (1)
restore pluggable database
recover pluggable database
alter database open;
alter pluggable database name open;
Oracle support says: You should be able to close the pdb and restore/recover the system tablespace of PDB.
* Inconsistent backups are usually created by taking online database backups. You can also make an inconsistent backup by backing up data files while a database is closed, either:
/ Immediately after the crash of an Oracle instance (or, in an Oracle RAC configuration, all instances) / After shutting down the database using SHUTDOWN ABORT
Inconsistent backups are only useful if the database is in ARCHIVELOG mode and all archived redo logs created since the backup are available.
* Open the database with the RESETLOGS option after finishing recovery: SQL> ALTER DATABASE OPEN RESETLOGS;
Q4. Which two statements are true?
A. A role cannot be assigned external authentication.
B. A role can be granted to other roles.
C. A role can contain both system and object privileges.
D. The predefined resource role includes the unlimited_tablespace privilege.
E. All roles are owned by the sys user.
F. The predefined connect role is always automatically granted to all new users at the time of their creation.
Answer: B,C
Reference: http://docs.oracle.com/cd/E11882_01/network.112/e36292/authorization.htm#DBSEG9987
8 (the functionality of roles)
Q5. A senior DBA asked you to execute the following command to improve performance:
SQL> ALTER TABLE subscribe log STORAGE (BUFFER_POOL recycle);
You checked the data in the SUBSCRIBE_LOG table and found that it is a large table
containing one million rows.
What could be a reason for this recommendation?
A. The keep pool is not configured.
B. Automatic Workarea Management is not configured.
C. Automatic Shared Memory Management is not enabled.
D. The data blocks in the SUBSCRIBE_LOG table are rarely accessed.
E. All the queries on the SUBSCRIBE_LOG table are rewritten to a materialized view.
Answer: D
Explanation: The most of the rows in SUBSCRIBE_LOG table are accessed once a week.
Q6. Which three statements are true about a job chain?
A. It can contain a nested chain of jobs.
B. It can be used to implement dependency-based scheduling.
C. It cannot invoke the same program or nested chain in multiple steps in the chain.
D. It cannot have more than one dependency.
E. It can be executed using event-based or time-based schedules.
Answer: A,B,E
Reference: http://docs.oracle.com/cd/B28359_01/server.111/b28310/scheduse009.htm#ADMIN12459
Q7. Your multitenant container database, CDB1, is running in ARCHIVELOG mode and has two pluggable databases, HR_PDB and ACCOUNTS_PDB. An RMAN backup exists for the database.
You issue the command to open ACCOUNTS_PDB and find that the USERDATA.DBF data file for the default permanent tablespace USERDATA belonging to ACCOUNTS_PDB is corrupted.
What should you do before executing the commands to restore and recover the data file in ACCOUNTS_PDB?
A. Place CDB1 in the mount stage and then the USERDATA tablespace offline in ACCOUNTS_PDB.
B. Place CDB1 in the mount stage and issue the ALTER PLUGGABLE DATABASE accounts_pdb CLOSE IMMEDIATE command.
C. Issue the ALTER PLUGGABLE DATABASE accounts_pdb RESTRICTED command.
D. Take the USERDATA tablespace offline in ACCOUNTS_PDB.
Answer: D
Explanation: * You can take an online tablespace offline so that it is temporarily unavailable for general use. The rest of the database remains open and available for users to access data. Conversely, you can bring an offline tablespace online to make the schema objects within the tablespace available to database users. The database must be open to alter the availability of a tablespace.
Q8. Oracle Grid Infrastructure for a stand-alone server is installed on your production host before installing the Oracle Database server. The database and listener are configured by using Oracle Restart.
Examine the following command and its output:
$ crsctl config has
CRS-4622: Oracle High Availability Services auto start is enabled.
What does this imply?
A. When you start an instance on a high with SQL *Plus dependent listeners and ASM disk groups are automatically started.
B. When a database instance is started by using the SRVCTL utility and listener startup fails, the instance is still started.
C. When a database is created by using SQL* Plus, it is automatically added to the Oracle Restart configuration.
D. When you create a database service by modifying the SERVICE_NAMES initialization parameter, it is automatically added to the Oracle Restart configuration.
Answer: B
Explanation: About Startup Dependencies Oracle Restart ensures that Oracle components are started in the proper order, in accordance with component dependencies. For example, if database files are stored in Oracle ASM disk groups, then before starting the database instance, Oracle Restart ensures that the Oracle ASM instance is started and the required disk groups are mounted. Likewise, if a component must be shut down, Oracle Restart ensures that dependent components are cleanly shut down first. Oracle Restart also manages the weak dependency between database instances and the Oracle Net listener (the listener): When a database instance is started, Oracle Restart attempts to start the listener. If the listener startup fails, then the database is still started. If the listener later fails, Oracle Restart does not shut down and restart any database instances.
http://docs.oracle.com/cd/E16655_01/server.121/e17636/restart.htm#ADMIN12710
Q9. Examine the parameters for your database instance:
Which three statements are true about the process of automatic optimization by using cardinality feedback?
A. The optimizer automatically changes a plan during subsequent execution of a SQL statement if there is a huge difference in optimizer estimates and execution statistics.
B. The optimizer can re optimize a query only once using cardinality feedback.
C. The optimizer enables monitoring for cardinality feedback after the first execution of a query.
D. The optimizer does not monitor cardinality feedback if dynamic sampling and multicolumn statistics are enabled.
E. After the optimizer identifies a query as a re-optimization candidate, statistics collected by the collectors are submitted to the optimizer.
Answer: A,C,D
Explanation: C: During the first execution of a SQL statement, an execution plan is generated as usual.
D: if multi-column statistics are not present for the relevant combination of columns, the optimizer can fall back on cardinality feedback.
(not B)* Cardinality feedback. This feature, enabled by default in 11.2, is intended to improve plans for repeated executions.
optimizer_dynamic_sampling optimizer_features_enable
* dynamic sampling or multi-column statistics allow the optimizer to more accurately estimate selectivity of conjunctive predicates.
Note:
* OPTIMIZER_DYNAMIC_SAMPLING controls the level of dynamic sampling performed by the optimizer. Range of values. 0 to 10
* Cardinality feedback was introduced in Oracle Database 11gR2. The purpose of this feature is to automatically improve plans for queries that are executed repeatedly, for which the optimizer does not estimate cardinalities in the plan properly. The optimizer may misestimate cardinalities for a variety of reasons, such as missing or inaccurate statistics, or complex predicates. Whatever the reason for the misestimate, cardinality feedback may be able to help.
Q10. What is the result of executing a TRUNCATE TABLE command on a table that has Flashback Archiving enabled?
A. It fails with the ORA-665610 Invalid DDL statement on history-tracked message
B. The rows in the table are truncated without being archived.
C. The rows in the table are archived, and then truncated.
D. The rows in both the table and the archive are truncated.
Answer: B
Explanation: You cannot roll back a TRUNCATE TABLE statement, nor can you use a FLASHBACK TABLE statement to retrieve the contents of a table that has been truncated.