Upgrade to OCP 12c 1Z0-060（21-30）

Upgrade to OCP 12c 1Z0-060（21-30）

Question 21:

Which three functions are performed by the SQL Tuning Advisor?
A. Building and implementing SQL profiles
B. Recommending the optimization of materialized views
C. Checking query objects for missing and stale statistics
D. Recommending bitmap, function-based, and B-tree indexes
E. Recommending the restructuring of SQL queries that are using bad plans
Answer: A,C,E
Explanation: The SQL Tuning Advisor takes one or more SQL statements as an input and invokes the Automatic Tuning Optimizer to perform SQL tuning on the statements. The output of the SQL Tuning Advisor is in the form of an advice or recommendations, along with a rationale for each recommendation and its expected benefit. The recommendation relates to collection of statistics on objects (C), creation of new indexes, restructuring of the SQL statement (E), or creation of a SQL profile (A). You can choose to accept the recommendation to complete the tuning of the SQL statements.

Question 22:

Examine the following command:
ALTER SYSTEM SET enable_ddl_logging=FALSE;
Which statement is true?
A. None of the data definition language (DDL) statements are logged in the trace file.
B. Only DDL commands that resulted in errors are logged in the alert log file.
C. A new log.xml file that contains the DDL statements is created, and the DDL command details are removed from the alert log file.
D. Only DDL commands that resulted in the creation of new database files are logged.
Answer: A
Explanation: ENABLE_DDL_LOGGING enables or disables the writing of a subset of data definition language (DDL) statements to a DDL alert log.
The DDL log is a file that has the same format and basic behavior as the alert log, but it only contains the DDL statements issued by the database. The DDL log is created only for the RDBMS component and only if the ENABLE_DDL_LOGGING initialization parameter is set to true. When this parameter is set to false, DDL statements are not included in any log.

Question 23:

Your multitenant container database (CDB) contains three pluggable database (PDBs).
You find that the control file is damaged. You plan to use RMAN to recover the control file.
There are no startup triggers associated with the PDBs.
Which three steps should you perform to recover the control file and make the database fully operational?
A. Mount the container database (CDB) and restore the control file from the control file auto backup.
B. Recover and open the CDB in NORMAL mode.
C. Mount the CDB and then recover and open the database, with the RESETLOGS option.
D. Open all the pluggable databases.
E. Recover each pluggable database.
F. Start the database instance in the nomount stage and restore the control file from control file auto backup.

Answer: C,D,F
Explanation:

Step 1: F
Step 2: D
Step 3: C: If all copies of the current control file are lost or damaged, then you must restore and mount a backup control file. You must then run the RECOVERcommand, even if no data files have been restored, and open the database with the RESETLOGS option.

Note:
* RMAN and Oracle Enterprise Manager Cloud Control (Cloud Control) provide full support for backup and recovery in a multitenant environment. You can back up and recover a whole multitenant container database (CDB), root only, or one or more pluggable databases (PDBs).

Question 24:

A new report process containing a complex query is written, with high impact on the database. You want to collect basic statistics about query, such as the level of parallelism, total database time, and the number of I/O requests.
For the database instance STATISTICS_LEVEL, the initialization parameter is set to TYPICAL and the CONTROL_MANAGEMENT_PACK_ACCESS parameter is set to DIAGNOSTIC+TUNING.
What should you do to accomplish this task?

A. Execute the query and view Active Session History (ASH) for information about the query.
B. Enable SQL trace for the query.
C. Create a database operation, execute the query, and use the DBMS_SQL_MONITOR.REPORT_SQL_MONITOR function to view the report.
D. Use the DBMS_APPLICATION_INFO.SET_SESSION_LONGOPS procedure to monitor query execution and view the information from the V$SESSION_LONGOPS view.
Answer: C
Explanation: The REPORT_SQL_MONITOR function is used to return a SQL monitoring report for a specific SQL statement.
Incorrect:
Not A: Not interested in session statistics, only in statistics for the particular SQL query.
Not B: We are interested in statistics, not tracing.
Not D: SET_SESSION_LONGOPS Procedure

This procedure sets a row in the V$SESSION_LONGOPS view. This is a view that is used to indicate the on-going progress of a long running operation. Some Oracle functions, such as parallel execution and Server Managed Recovery, use rows in this view to indicate the status of, for example, a database backup.
Applications may use the SET_SESSION_LONGOPS procedure to advertise information on the progress of application specific long running tasks so that the progress can be monitored by way of the V$SESSION_LONGOPS view.

Question 25:

Identify two valid options for adding a pluggable database (PDB) to an existing multitenant container database (CDB).
A. Use the CREATE PLUGGABLE DATABASE statement to create a PDB using the files from the SEED.
B. Use the CREATE DATABASE . . . ENABLE PLUGGABLE DATABASE statement to provision a PDB by copying file from the SEED.
C. Use the DBMS_PDB package to clone an existing PDB.
D. Use the DBMS_PDB package to plug an Oracle 12c non-CDB database into an existing CDB.
E. Use the DBMS_PDB package to plug an Oracle 11 g Release 2 (11.2.0.3.0) non-CDB database into an existing CDB.
Answer: A,D

Question 26:

Your database supports a DSS workload that involves the execution of complex queries:
Currently, the library cache contains the ideal workload for analysis. You want to analyze some of the queries for an application that are cached in the library cache.
What must you do to receive recommendations about the efficient use of indexes and materialized views to improve query performance?

A. Create a SQL Tuning Set (STS) that contains the queries cached in the library cache and run the SQL Tuning Advisor (STA) on the workload captured in the STS.
B. Run the Automatic Workload Repository Monitor (ADDM).
C. Create an STS that contains the queries cached in the library cache and run the SQL Performance Analyzer (SPA) on the workload captured in the STS.
D. Create an STS that contains the queries cached in the library cache and run the SQL Access Advisor on the workload captured in the STS.
Answer: D
Explanation: * SQL Access Advisor is primarily responsible for making schema modification recommendations, such as adding or dropping indexes and materialized views. SQL Tuning Advisor makes other types of recommendations, such as creating SQL profiles and restructuring SQL statements.
* The query optimizer can also help you tune SQL statements. By using SQL Tuning Advisor and SQL Access Advisor, you can invoke the query optimizer in advisory mode to examine a SQL statement or set of statements and determine how to improve their efficiency. SQL Tuning Advisor and SQL Access Advisor can make various recommendations, such as creating SQL profiles, restructuring SQL statements, creating additional indexes or materialized views, and refreshing optimizer statistics.

Note:
* Decision support system (DSS) workload
* The library cache is a shared pool memory structure that stores executable SQL and PL/SQL code. This cache contains the shared SQL and PL/SQL areas and control structures such as locks and library cache handles.
Reference: Tuning SQL Statements

Question 27:

The following parameter are set for your Oracle 12c database instance:
OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES=FALSE
OPTIMIZER_USE_SQL_PLAN_BASELINES=TRUE
You want to manage the SQL plan evolution task manually. Examine the following steps:
1. Set the evolve task parameters.
2. Create the evolve task by using the DBMS_SPM.CREATE_EVOLVE_TASK function.

3. Implement the recommendations in the task by using the DBMS_SPM.IMPLEMENT_EVOLVE_TASK function.
4. Execute the evolve task by using the DBMS_SPM.EXECUTE_EVOLVE_TASK function.
5. Report the task outcome by using the DBMS_SPM.REPORT_EVOLVE_TASK function.
Identify the correct sequence of steps:
A. 2, 4, 5
B. 2, 1, 4, 3, 5
C. 1, 2, 3, 4, 5
D. 1, 2, 4, 5
Answer: B

Explanation: * Evolving SQL Plan Baselines

2. Create the evolve task by using the DBMS_SPM.CREATE_EVOLVE_TASK function.
This function creates an advisor task to prepare the plan evolution of one or more plans for a specified SQL statement. The input parameters can be a SQL handle, plan name or a list of plan names, time limit, task name, and description.
1. Set the evolve task parameters.
SET_EVOLVE_TASK_PARAMETER
This function updates the value of an evolve task parameter. In this release, the only valid parameter is TIME_LIMIT.

4. Execute the evolve task by using the DBMS_SPM.EXECUTE_EVOLVE_TASK function.
This function executes an evolution task. The input parameters can be the task name, execution name, and execution description. If not specified, the advisor generates the name, which is returned by the function.
3: IMPLEMENT_EVOLVE_TASK
This function implements all recommendations for an evolve task. Essentially, this function is equivalent to using ACCEPT_SQL_PLAN_BASELINE for all recommended plans. Input parameters include task name, plan name, owner name, and execution name.
5. Report the task outcome by using the DBMS_SPM_EVOLVE_TASK function.
This function displays the results of an evolve task as a CLOB. Input parameters include the task name and section of the report to include.
Reference: Oracle Database SQL Tuning Guide 12c, Managing SQL Plan Baselines

Question 28:

In a recent Automatic Workload Repository (AWR) report for your database, you notice a high number of buffer busy waits. The database consists of locally managed tablespaces with free list managed segments.
On further investigation, you find that buffer busy waits is caused by contention on data blocks.
Which option would you consider first to decrease the wait event immediately?
A. Decreasing PCTUSED
B. Decreasing PCTFREE
C. Increasing the number of DBWN process
D. Using Automatic Segment Space Management (ASSM)
E. Increasing db_buffer_cache based on the V$DB_CACHE_ADVICE recommendation
Answer: D
Explanation: * Automatic segment space management (ASSM) is a simpler and more efficient way of managing space within a segment. It completely eliminates any need to specify and tune the pctused,freelists, and freelist groups storage parameters for schema objects created in the tablespace. If any of these attributes are specified, they are ignored.

* Oracle introduced Automatic Segment Storage Management (ASSM) as a replacement for traditional freelists management which used one-way linked-lists to manage free blocks with tables and indexes. ASSM is commonly called "bitmap freelists" because that is how Oracle implement the internal data structures for free block management.
Note:
* Buffer busy waits are most commonly associated with segment header contention onside the data buffer pool (db_cache_size, etc.).
* The most common remedies for high buffer busy waits include database writer (DBWR) contention tuning, adding freelists (or ASSM), and adding missing indexes.

Question 29:

Examine this command:
SQL > exec DBMS_STATS.SET_TABLE_PREFS (‘SH’, ‘CUSTOMERS’, ‘PUBLISH’, ‘false’);
Which three statements are true about the effect of this command?
A. Statistics collection is not done for the CUSTOMERS table when schema stats are gathered.
B. Statistics collection is not done for the CUSTOMERS table when database stats are gathered.
C. Any existing statistics for the CUSTOMERS table are still available to the optimizer at parse time.
D. Statistics gathered on the CUSTOMERS table when schema stats are gathered are stored as pending statistics.
E. Statistics gathered on the CUSTOMERS table when database stats are gathered are stored as pending statistics.
Answer: C,D,E
Explanation: * SET_TABLE_PREFS Procedure

This procedure is used to set the statistics preferences of the specified table in the specified schema.
* Example:

Using Pending Statistics
Assume many modifications have been made to the employees table since the last time statistics were gathered. To ensure that the cost-based optimizer is still picking the best plan, statistics should be gathered once again; however, the user is concerned that new statistics will cause the optimizer to choose bad plans when the current ones are acceptable. The user can do the following:
EXEC DBMS_STATS.SET_TABLE_PREFS('hr', 'employees', 'PUBLISH', 'false');
By setting the employees tables publish preference to FALSE, any statistics gather from now on will not be automatically published. The newly gathered statistics will be marked as pending.

Question 30:

Examine the following impdp command to import a database over the network from a pre-12c Oracle database (source):

Which three are prerequisites for successful execution of the command?
A. The import operation must be performed by a user on the target database with the DATAPUMP_IMP_FULL_DATABASE role, and the database link must connect to a user on the source database with the DATAPUMP_EXD_FULL_DATABASE role.
B. All the user-defined tablespaces must be in read-only mode on the source database.
C. The export dump file must be created before starting the import on the target database.
D. The source and target database must be running on the same platform with the same endianness.
E. The path of data files on the target database must be the same as that on the source database.
F. The impdp operation must be performed by the same user that performed the expdp operation.

Answer: A,B,D
Explanation: In this case we have run the impdp without performing any conversion if endian format is different then we have to first perform conversion.