1z0-076 Exam Dumps - Oracle Certification Questions and Answers

The rate of SQL apply on a logical standby database can be influenced by:

• A: The number of PREPARER processes (which seems to be a typographical error and should read as PREPARER or similar) which prepare the redo data for the applier processes.
• B: The number of coordinator processes on the standby database instance which coordinate the SQL apply activities.
• C: The number of full table scans performed by SQL apply since full table scans can be resource-intensive and slow down the apply rate.
• E: The number of applier processes which apply the redo data to the logical standby database.

Option D is incorrect as the size of the undo tablespace on the logical standby database is more likely to affect the SQL apply lag rather than the rate of SQL apply.

Option F is incorrect because the size of the shared pool would typically not influence the rate of SQL apply. The shared pool is more related to the caching of shared SQL and PL/SQL code and control structures.

References: Oracle's documentation on SQL Apply in Data Guard configurations discusses the factors affecting the performance of SQL Apply operations on logical standby databases.

A logical standby database is part of Oracle Data Guard and allows the standby database to be open for read-write operations, providing additional flexibility. The requirements met by a logical standby database include:

• Support for workloads requiring additional materialized views (A): Logical standby databases can support materialized views, allowing for complex data summarization and reporting workloads.
• It can be used to create additional tables (C): Unlike physical standby databases, logical standby databases allow for the creation of additional tables that do not exist in the primary database, enabling custom workloads and reporting.
• It can be used for Real Application Testing without affecting the disaster recovery capabilities (E): Logical standby databases can be used to test application changes, patches, and upgrades while still maintaining their role as part of the disaster recovery strategy.
• Support for workloads requiring additional indexes (F): Logical standby databases allow for the creation of additional indexes to optimize query performance for reporting and analytical workloads.References:
• Oracle Data Guard Concepts and Administration
• Oracle Database High Availability Overview

Enterprise Manager Cloud Control provides a graphical interface to manage multiple standby databases, simplify switchovers and failovers, and automate failover processes to a specified target standby database. It offers a comprehensive view and control over the Data Guard configuration, making complex operations more manageable.

DGMGRL is a command-line tool specifically designed for managing Data Guard configurations. It allows the administration of multiple standby databases, simplifies the execution of switchovers and failovers, reinstatements, and conversions to and from snapshot standby databases, and supports the automation of failover processes to a specified standby database.

Other options like RMAN, SQL*Plus, CRSCTL, SRVCTL, and GDCCTL do not provide the same level of integrated management functionality for Data Guard environments as Enterprise Manager Cloud Control and DGMGRL.

Based on the Oracle Database 19c documentation, the correct answers about SQL Apply filters for a logical standby database are:A. They can be used to skip execution of DML triggers on a table while allowing the DML to execute.B. They can be used to skip CREATE TABLE commands.C. They can be used to skip ALTER SYSTEM and ALTER DATABASE commands.G. They can be used to skip ALTER TABLE commands on specific tables.

Comprehensive Detailed Explanation:SQL Apply filters in a logical standby database can be set to control which SQL operations are applied to the standby. These filters allow for certain commands to be skipped, ensuring that they do not impact the standby database. For example, filters can be used to skip the execution of DML triggers to prevent them from firing during SQL Apply, while still allowing the underlying DML to be executed on the logical standby database. This is particularly useful when certain triggers are not desired to run in a standby environment. CREATE TABLE, ALTER SYSTEM, ALTER DATABASE, and specific ALTER TABLE commands can also be skipped using SQL Apply filters to prevent unwanted structural changes or administrative operations from affecting the logical standby database. These capabilities provide a level of control to ensure that the logical standby database reflects only the desired state of the primary database.

References:Oracle Database SQL Language Reference and Oracle Data Guard Concepts and Administration guide offer comprehensive details on the use of SQL Apply filters, including the range of SQL statements that can be influenced by these filters in a logical standby database environment.

The execution of the UNSKIP procedure is designed to remove SQL Apply filters that have been previously set up on a logical standby database. Based on the provided statements, the UNSKIP procedure is directed to delete any SQL Apply filters for DML statements associated with objects in the 'HR' schema that start with 'EMP'. Since both SKIP procedures had the same schema name ('HR') and statement type ('DML'), and the UNSKIP procedure uses a wildcard (%) for the object name, it will successfully remove both of the SQL Apply filters for 'EMP_NEW' and 'EMP_OLD', as both object names match the pattern provided in the UNSKIP procedure.

References:Oracle's Data Guard documentation and SQL Language Reference provide insights into managing SQL Apply filters on a logical standby database using the DBMS_LOGSTDBY package. This includes adding and removing filters through SKIP and UNSKIP procedures.

In a Data Guard configuration where the protection mode is set to Maximum Availability and synchronous redo transport is enabled, if the standby destination fails to acknowledge the reception of redo within the net_timeout period, the primary database will terminate the synchronous redo transport mode connections to the standby database to protect the primary database from hanging (C). The primary database then operates in a Maximum Performance mode until the issue is resolved. This behavior ensures that the primary database can continue to process transactions even when the standby database is temporarily unavailable.

References:The Oracle Data Guard Broker documentation and Oracle Data Guard Concepts and Administration guide detail the behavior of different protection modes and the response to network timeouts, including the fallback to asynchronous redo transport to maintain primary database availability.

• DB_NAME (A): The name of the database, which should remain consistent across the primary and standby databases.
• db_file_name_convert (C): This parameter helps define the mapping of data file names from the primary to the standby database, which is crucial during the creation and operation of a standby database.
• COMPATIBLE (D): The compatibility level can influence the features that can be used on the standby database and must be consistent with or higher than that of the primary database, especially after upgrades.
• STANDBY_ARCHIVE_DEST (F): This parameter specifies the destination of archived redo log files on the standby database, which is important for log transport and apply services.

References:

• Oracle Data Guard Concepts and Administration Guide
• Oracle Database Reference

D. The database role indicated by FS_FAILOVER_STATUS as BYSTANDER implies that the database is a standby database in the Data Guard configuration. This means the database is neither a primary database nor an active failover target.

E. Since the FS_FAILOVER_OBSERVER_HOST column shows cats, it suggests that this is the host on which the observer would run. However, because the FS_FAILOVER_OBSERVER_PRESENT column is not shown, we cannot definitively state if the observer is currently connected or not. If FS_FAILOVER_OBSERVER_PRESENT is 'YES', the observer is connected, if 'NO', then it's not. In the absence of this column's output, the best assumption based on the available data is that the observer is not connected.

The output shows that the FS_FAILOVER_STATUS is BYSTANDER, which indicates that the database in question is not actively involved in a fast-start failover configuration as a primary or standby. It is in a bystander role, meaning that while it is part of a Data Guard configuration, it is neither a target for failover nor actively participating in failover operations. Additionally, FS_FAILOVER_OBSERVER_HOST shows 'cats', which indicates the host where the observer process is expected to run. However, since there is no information about the observer being present, we can infer that although 'cats' is designated for the observer to run, the observer is not currently connected to this database.

ReferencesOracle documentation on Data Guard configurations and the V$DATABASE view which provides information about the fast-start failover status and observer host.

Creating dedicated database services for each database instance (Option D) and utilizing event triggers to manage these services based on the role of the database (Option E) ensure that clients connect to the appropriate database instance based on its current role and state. This approach leverages the flexibility and control provided by Oracle Net services and database event management to direct client connections to the suitable primary or standby instance, enhancing the overall robustness and reliability of the Data Guard environment. References: Based on Oracle Database 19c best practices for managing connectivity and services in a Data Guard setup, including the use of role-based services and event-driven service management.

When enabling fast-start failover, certain conditions must be met:

• The fastStartFailoverTarget property is not set on Dogs (A): The primary database (Dogs) needs to have a fast-start failover target configured for the operation to succeed.
• The LogXptMode property is set to ASYNC on Sheep while Sheep is the target standby database (B): Fast-start failover requires synchronous redo transport (SYNC or FASTSYNC) to ensure zero data loss, which is a prerequisite for enabling the feature.
• The LogXptMode property is set to ASYNC on Dogs (D): Similar to the previous point, the primary database must be configured to use synchronous redo transport for the fast-start failover to be possible.References:
• Oracle Data Guard Broker documentation
• Oracle Database Error Messages Guide