1Z0-062 | The Secret of Oracle 1Z0-062 dumps
Q91. Which two statements are true about variable extent size support for large ASM files?
A. The metadata used to track extents in SGA is reduced.
B. Rebalance operations are completed faster than with a fixed extent size
C. An ASM Instance automatically allocates an appropriate extent size.
D. Resync operations are completed faster when a disk comes online after being taken offline.
E. Performance improves in a stretch cluster configuration by reading from a local copy of an extent.
Answer: A,C
Explanation: A: Variable size extents enable support for larger ASM datafiles, reduce SGA memory requirements for very large databases (A), and improve performance for file create and open operations.
C: You don't have to worry about the sizes; the ASM instance automatically allocates the appropriate extent size.
Note:
* The contents of ASM files are stored in a disk group as a set, or collection, of data extents that are stored on individual disks within disk groups. Each extent resides on an individual disk. Extents consist of one or more allocation units (AU). To accommodate increasingly larger files, ASM uses variable size extents.
* The size of the extent map that defines a file can be smaller by a factor of 8 and 64 depending on the file size. The initial extent size is equal to the allocation unit size and it increases by a factor of 8 and 64 at predefined thresholds. This feature is automatic for newly created and resized datafiles when the disk group compatibility attributes are set to Oracle Release 11 or higher.
Q92. Which three statements are true concerning the multitenant architecture?
A. Each pluggable database (PDB) has its own set of background processes.
B. A PDB can have a private temp tablespace.
C. PDBs can share the sysaux tablespace.
D. Log switches occur only at the multitenant container database (CDB) level.
E. Different PDBs can have different default block sizes.
F. PDBs share a common system tablespace.
G. Instance recovery is always performed at the CDB level.
Answer: B,D,G
Explanation: B:
* A PDB would have its SYSTEM, SYSAUX, TEMP tablespaces.It can also contains other
user created tablespaces in it.
* There is one default temporary tablespace for the entire CDB. However, you can create additional temporary tablespaces in individual PDBs.
D:
* There is a single redo log and a single control file for an entire CDB
* A log switch is the point at which the database stops writing to one redo log file and begins writing to another. Normally, a log switch occurs when the current redo log file is completely filled and writing must continue to the next redo log file.
G: instance recovery The automatic application of redo log records to uncommitted data blocks when an database instance is restarted after a failure.
Incorrect: Not A:
* There is one set of background processes shared by the root and all PDBs. –
* High consolidation density. The many pluggable databases in a single container database share its memory and background processes, letting you operate many more pluggable databases on a particular platform than you can single databases that use the old architecture.
Not C: There is a separate SYSAUX tablespace for the root and for each PDB.
Not F: There is a separate SYSTEM tablespace for the root and for each PDB. -
Q93. Which three operations can be performed as multipartition operations in Oracle?
A. Merge partitions of a list partitioned table
B. Drop partitions of a list partitioned table
C. Coalesce partitions of a hash-partitioned global index.
D. Move partitions of a range-partitioned table
E. Rename partitions of a range partitioned table
F. Merge partitions of a reference partitioned index
Answer: A,B,F
Explanation: Multipartition maintenance enables adding, dropping, truncate, merge, split operations on multiple partitions.
A: Merge Multiple Partitions:
The new “ALTER TABLE … MERGE PARTITIONS ” help merge multiple partitions or subpartitions with a single statement. When merging multiple partitions, local and global index operations and semantics for inheritance of unspecified physical attributes are the same for merging two partitions.
B: Drop Multiple Partitions:
The new “ALTER TABLE … DROP PARTITIONS ” help drop multiple partitions or subpartitions with a single statement.
Example:
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SQL> ALTER TABLE Tab_tst1 DROP PARTITIONS
Tab_tst1_PART5, Tab_tst1_PART6, Tab_tst1_PART7;
Table altered
SQL>
Restrictions :
-You can’t drop all partitions of the table.
-If the table has a single partition, you will get the error: ORA-14083: cannot drop the only partition of a partitioned.
Q94. What is the effect of specifying the "ENABLE PLUGGABLE DATABASE" clause in a "CREATE DATABASE” statement?
A. It will create a multitenant container database (CDB) with only the root opened.
B. It will create a CDB with root opened and seed read only.
C. It will create a CDB with root and seed opened and one PDB mounted.
D. It will create a CDB that must be plugged into an existing CDB.
E. It will create a CDB with root opened and seed mounted.
Answer: B
Explanation: * The CREATE DATABASE ... ENABLE PLUGGABLE DATABASE SQL statement creates a new CDB. If you do not specify the ENABLE PLUGGABLE DATABASE clause, then the newly created database is a non-CDB and can never contain PDBs.
Along with the root (CDB$ROOT), Oracle Database automatically creates a seed PDB (PDB$SEED). The following graphic shows a newly created CDB:
Description of admin095.png follows
* Creating a PDB Rather than constructing the data dictionary tables that define an empty PDB from scratch, and then populating its Obj$ and Dependency$ tables, the empty PDB is created when the CDB is created. (Here, we use empty to mean containing no customer-created artifacts.) It is referred to as the seed PDB and has the name PDB$Seed. Every CDB non-negotiably contains a seed PDB; it is non-negotiably always open in read-only mode. This has no conceptual significance; rather, it is just an optimization device. The create PDB operation is implemented as a special case of the clone PDB operation.
Q95. Identify three benefits of Unified Auditing.
A. Decreased use of storage to store audit trail rows in the database.
B. It improves overall auditing performance.
C. It guarantees zero-loss auditing.
D. The audit trail cannot be easily modified because it is read-only.
E. It automatically audits Recovery Manager (RMAN) events.
Answer: A,B,E
Explanation: A: Starting with 12c, Oracle has unified all of the auditing types into one single unit called Unified auditing. You don’t have to turn on or off all of the different auidting types individually and as a matter of fact auditing is enabled by default right out of the box. The AUD$ and FGA$ tables have been replaced with one single audit trail table. All of the audit data is now stored in Secure Files table thus improving the overall management aspects of audit data itself.
B: Further the audit data can also be buffered solving most of the common performance related problems seen on busy environments.
E: Unified Auditing is able to collect audit data for Fine Grained Audit, RMAN, Data Pump, Label Security, Database Vault and Real Application Security operations.
Note:
* Benefits of the Unified Audit Trail
The benefits of a unified audit trail are many: / (B) Overall auditing performance is greatly improved. The default mode that unified audit works is Queued Write mode. In this mode, the audit records are batched in SGA queue and is persisted in a periodic way. Because the audit records are written to SGA queue, there is a significant performance improvement.
/ The unified auditing functionality is always enabled and does not depend on the initialization parameters that were used in previous releases
/ (A) The audit records, including records from the SYS audit trail, for all the audited components of your Oracle Database installation are placed in one location and in one format, rather than your having to look in different places to find audit trails in varying formats. This consolidated view enables auditors to co-relate audit information from different components. For example, if an error occurred during an INSERT statement, standard auditing can indicate the error number and the SQL that was executed. Oracle Database Vault-specific information can indicate whether this error happened because of a command rule violation or realm violation. Note that there will be two audit records with a distinct AUDIT_TYPE. With this unification in place, SYS audit records appear with AUDIT_TYPE set to Standard Audit.
/ The management and security of the audit trail is also improved by having it in single audit trail.
/ You can create named audit policies that enable you to audit the supported components listed at the beginning of this section, as well as SYS administrative users. Furthermore, you can build conditions and exclusions into your policies.
* Oracle Database 12c Unified Auditing enables selective and effective auditing inside the Oracle database using policies and conditions. The new policy based syntax simplifies management of auditing within the database and provides the ability to accelerate auditing based on conditions.
* The new architecture unifies the existing audit trails into a single audit trail, enabling simplified management and increasing the security of audit data generated by the database.
Q96. Which three activities are supported by the Data Recovery Advisor?
A. Advising on block checksum failures
B. Advising on inaccessible control files
C. Advising on inaccessible block change tracking files
D. Advising on empty password files
E. Advising on invalid block header field values
Answer: A,B,E
Explanation: * Data Recovery Advisor can diagnose failures such as the following:
/ (B) Components such as datafiles and control files that are not accessible because they do not exist, do not have the correct access permissions, have been taken offline, and so on
/ (A, E) Physical corruptions such as block checksum failures and invalid block header field values
/ Inconsistencies such as a datafile that is older than other database files / I/O failures such as hardware errors, operating system driver failures, and exceeding operating system resource limits (for example, the number of open files)
* The Data Recovery Advisor automatically diagnoses corruption or loss of persistent data on disk, determines the appropriate repair options, and executes repairs at the user's request. This reduces the complexity of recovery process, thereby reducing the Mean Time To Recover (MTTR).
Q97. Your multitenant container database (CDB) contains pluggable databases (PDBs), you are connected to the HR_PDB. You execute the following command:
SQL > CREATE UNDO TABLESPACE undotb01
DATAFILE ‘u01/oracle/rddb1/undotbs01.dbf’ SIZE 60M AUTOEXTEND ON;
What is the result?
A. It executes successfully and creates an UNDO tablespace in HR_PDB.
B. It falls and reports an error because there can be only one undo tablespace in a CDB.
C. It fails and reports an error because the CONTAINER=ALL clause is not specified in the command.
D. It fails and reports an error because the CONTAINER=CURRENT clause is not specified in the command.
E. It executes successfully but neither tablespace nor the data file is created.
Answer: E
Explanation: Interesting behavior in 12.1.0.1 DB of creating an undo tablespace in a PDB. With the new Multitenant architecture the undo tablespace resides at the CDB level and PDBs all share the same UNDO tablespace.
When the current container is a PDB, an attempt to create an undo tablespace fails without returning an error.
Q98. Examine the following commands for redefining a table with Virtual Private Database (VPD) policies:
Which two statements are true about redefining the table?
A. All the triggers for the table are disabled without changing any of the column names or column types in the table.
B. The primary key constraint on the EMPLOYEES table is disabled during redefinition.
C. VPD policies are copied from the original table to the new table during online redefinition.
D. You must copy the VPD policies manually from the original table to the new table during online redefinition.
Answer: B,C
Explanation: C (not D): CONS_VPD_AUTO Used to indicate to copy VPD policies automatically
* DBMS_RLS.ADD_POLICY / The DBMS_RLS package contains the fine-grained access control administrative interface, which is used to implement Virtual Private Database (VPD).DBMS_RLS is available with the Enterprise Edition only.
Note:
* CONS_USE_PK and CONS_USE_ROWID are constants used as input to the "options_flag" parameter in both the START_REDEF_TABLE Procedure and CAN_REDEF_TABLE Procedure. CONS_USE_ROWID is used to indicate that the
redefinition should be done using rowids while CONS_USE_PK implies that the redefinition should be done using primary keys or pseudo-primary keys (which are unique keys with all component columns having NOT NULL constraints).
* DBMS_REDEFINITION.START_REDEF_TABLE To achieve online redefinition, incrementally maintainable local materialized views are used. These logs keep track of the changes to the master tables and are used by the materialized views during refresh synchronization.
* START_REDEF_TABLE Procedure Prior to calling this procedure, you must manually create an empty interim table (in the same schema as the table to be redefined) with the desired attributes of the post-redefinition table, and then call this procedure to initiate the redefinition.
Q99. Which three statements are true about SQL plan directives?
A. They are tied to a specific statement or SQL ID.
B. They instruct the maintenance job to collect missing statistics or perform dynamic sampling to generate a more optimal plan.
C. They are used to gather only missing statistics.
D. They are created for a query expression where statistics are missing or the cardinality estimates by the optimizer are incorrect.
E. They instruct the optimizer to create only column group statistics.
F. Improve plan accuracy by persisting both compilation and execution statistics in the SYSAUX tablespace.
Answer: B,D,E
Explanation: During SQL execution, if a cardinality misestimate occurs, then the database creates SQL plan directives. During SQL compilation, the optimizer examines the query corresponding to the directive to determine whether missing extensions or histograms exist (D). The optimizer records any missing extensions. Subsequent DBMS_STATS calls collect statistics for the extensions.
The optimizer uses dynamic sampling whenever it does not have sufficient statistics corresponding to the directive. (B, not C)
E: Currently, the optimizer monitors only column groups. The optimizer does not create an extension on expressions.
Incorrect:
Not A: SQL plan directives are not tied to a specific SQL statement or SQL ID.
Note:
* A SQL plan directive is additional information and instructions that the optimizer can use to generate a more optimal plan. For example, a SQL plan directive can instruct the optimizer to record a missing extension.