1Z0-062 | Realistic Database 12c 1Z0-062 examcollection
Q21. Your are the DBA supporting an Oracle 11g Release 2 database and wish to move a table containing several DATE, CHAR, VARCHAR2, and NUMBER data types, and the table’s indexes, to another tablespace.
The table does not have a primary key and is used by an OLTP application.
Which technique will move the table and indexes while maintaining the highest level of availability to the application?
A. Oracle Data Pump.
B. An ALTER TABLE MOVE to move the table and ALTER INDEX REBUILD to move the indexes.
C. An ALTER TABLE MOVE to move the table and ALTER INDEX REBUILD ONLINE to move the indexes.
D. Online Table Redefinition.
E. Edition-Based Table Redefinition.
Answer: D
Explanation: * Oracle Database provides a mechanism to make table structure modifications without significantly affecting the availability of the table. The mechanism is called online table redefinition. Redefining tables online provides a substantial increase in availability compared to traditional methods of redefining tables.
* To redefine a table online:
Choose the redefinition method: by key or by rowid
* By key—Select a primary key or pseudo-primary key to use for the redefinition. Pseudo-primary keys are unique keys with all component columns having NOT NULL constraints. For this method, the versions of the tables before and after redefinition should have the same primary key columns. This is the preferred and default method of redefinition.
* By rowid—Use this method if no key is available. In this method, a hidden column named M_ROW$$ is added to the post-redefined version of the table. It is recommended that this column be dropped or marked as unused after the redefinition is complete. If COMPATIBLE is set to 10.2.0 or higher, the final phase of redefinition automatically sets this column unused. You can then use the ALTER TABLE ... DROP UNUSED COLUMNS statement to drop it.
You cannot use this method on index-organized tables.
Note:
* When you rebuild an index, you use an existing index as the data source. Creating an index in this manner enables you to change storage characteristics or move to a new tablespace. Rebuilding an index based on an existing data source removes intra-block fragmentation. Compared to dropping the index and using the CREATE INDEX statement, re-creating an existing index offers better performance.
Incorrect:
Not E: Edition-based redefinition enables you to upgrade the database component of an application while it is in use, thereby minimizing or eliminating down time.
Q22. Which two statements are true about standard database auditing? (Choose two.)
A. DDL statements can be audited.
B. Statements that refer to standalone procedure can be audited.
C. Operations by the users logged on as SYSDBA cannot be audited.
D. Only one audit record is ever created for a session per audited statement even though it is executed more than once.
Answer: A,B
Q23. Identify three scenarios in which you would recommend the use of SQL Performance Analyzer to analyze impact on the performance of SQL statements.
A. Change in the Oracle Database version
B. Change in your network infrastructure
C. Change in the hardware configuration of the database server
D. Migration of database storage from non-ASM to ASM storage
E. Database and operating system upgrade
Answer: A,C,E
Explanation: Oracle 11g/12c makes further use of SQL tuning sets with the SQL Performance Analyzer, which compares the performance of the statements in a tuning set before and after a database change. The database change can be as major or minor as you like, such as:
* (E) Database, operating system, or hardware upgrades.
* (A,C) Database, operating system, or hardware configuration changes.
* Database initialization parameter changes.
* Schema changes, such as adding indexes or materialized views.
* Refreshing optimizer statistics.
* Creating or changing SQL profiles.
Q24. You upgrade your Oracle database in a multiprocessor environment. As a recommended you execute the following script:
SQL > @utlrp.sql
Which two actions does the script perform?
A. Parallel compilation of only the stored PL/SQL code
B. Sequential recompilation of only the stored PL/SQL code
C. Parallel recompilation of any stored PL/SQL code
D. Sequential recompilation of any stored PL/SQL code
E. Parallel recompilation of Java code
F. Sequential recompilation of Java code
Answer: C,E
Explanation: utlrp.sql and utlprp.sql
The utlrp.sql and utlprp.sql scripts are provided by Oracle to recompile all invalid objects in the database. They are typically run after major database changes such as upgrades or patches. They are located in the $ORACLE_HOME/rdbms/admin directory and provide a wrapper on the UTL_RECOMP package. The utlrp.sql script simply calls the utlprp.sql script with a command line parameter of "0". The utlprp.sql accepts a single integer parameter that indicates the level of parallelism as follows.
0 - The level of parallelism is derived based on the CPU_COUNT parameter.
1 - The recompilation is run serially, one object at a time.
N - The recompilation is run in parallel with "N" number of threads.
Both scripts must be run as the SYS user, or another user with SYSDBA, to work correctly.
Reference: Recompiling Invalid Schema Objects
Q25. You plan to create a database by using the Database Configuration Assistant (DBCA), with the following specifications:
Applications will connect to the database via a middle tier.
The number of concurrent user connections will be high.
The database will have mixed workload, with the execution of complex BI queries scheduled at night.
Which DBCA option must you choose to create the database?
A. a General Purpose database template with default memory allocation
B. a Data Warehouse database template, with the dedicated server mode option and AMM enabled
C. a General Purpose database template, with the shared server mode option and Automatic Memory Management (AMM) enabled
D. a default database configuration
Answer: C
Reference: http://www.oracledistilled.com/oracle-database/administration/creating-a-database-using-database-configuration-assistant/
Q26. Which three factors influence the optimizer's choice of an execution plan?
A. the optimizer_mode initialization parameter
B. operating system (OS) statistics
C. cardinality estimates
D. object statistics in the data dictionary
E. fixed baselines
Answer: A,B
Reference: http://docs.oracle.com/cd/B19306_01/server.102/b14211/optimops.htm
Q27. Which task would you recommend before using the Database Upgrade Assistant (DBUA) to upgrade a single-instance Oracle 11g R2 database to Oracle Database 12c?
A. shutting down the database instance that is being upgraded
B. executing the catctl.pl script to run the upgrade processes in parallel
C. running the Pre-Upgrade Information Tool
D. copying the listener.ora file to the new ORACLE_HOME
Answer: C
Reference: http://docs.oracle.com/cd/E11882_01/server.112/e23633/upgrade.htm#UPGRD12395
Q28. Your database supports an online transaction processing (OLTP) application. The application is undergoing some major schema changes, such as addition of new indexes and materialized views. You want to check the impact of these changes on workload performance.
What should you use to achieve this?
A. Database replay
B. SQL Tuning Advisor
C. SQL Access Advisor
D. SQL Performance Analyzer
E. Automatic Workload Repository compare reports
Answer: D
Explanation: You can use the SQL Performance Analyzer to analyze the SQL performance impact of any type of system change. Examples of common system changes include:
.Database upgrades
.Configuration changes to the operating system, hardware, or database
.Database initialization parameter changes
.Schema changes, such as adding new indexes or materialized views
.Gathering optimizer statistics
.SQL tuning actions, such as creating SQL profiles
http://docs.oracle.com/cd/B28359_01/server.111/b28318/intro.htm#CNCPT961
Q29. Which two statements are true about the Automatic Database Diagnostic Monitor (ADDM)? (Choose two.)
A. The ADDM requires at least four AWR snapshots for analysis
B. The ADDM runs after each AWR snapshot is collected automatically by MMON
C. The results of the ADDM analysis are stored in the Automatic Workload Repository (AWR)
D. The ADDM analysis provides only diagnostics information but does not provide recommendations
E. The ADDM calls other advisors if required, but does not provide recommendations about the advisors
Answer: B,C
Q30. You have altered a non-unique index to be invisible to determine if queries execute within an acceptable response time without using this index.
Which two are possible if table updates are performed which affect the invisible index columns?
A. The index remains invisible.
B. The index is not updated by the DML statements on the indexed table.
C. The index automatically becomes visible in order to have it updated by DML on the table.
D. The index becomes unusable but the table is updated by the DML.
E. The index is updated by the DML on the table.
Answer: A,E
Explanation: Unlike unusable indexes, an invisible index is maintained during DML statements.
Note:
* Oracle 11g allows indexes to be marked as invisible. Invisible indexes are maintained like any other index, but they are ignored by the optimizer unless the OPTIMIZER_USE_INVISIBLE_INDEXES parameter is set to TRUE at the instance or session level. Indexes can be created as invisible by using the INVISIBLE keyword, and their visibility can be toggled using the ALTER INDEX command.