The command ALTER DATABASE FLASHBACK ON; enables the Flashback Database feature, which

provides a way to quickly revert an entire Oracle database back to a previous point in time. This

command can be executed while an Oracle 19c primary database is either open (option A) or

mounted (option B). It is also applicable to an Oracle 19c logical standby database while SQL Apply is

active (option E). However, it's important to note that enabling Flashback Database on the primary

does not automatically enable it on all associated standby databases, whether they are physical or

logical. Each database in a Data Guard configuration must have Flashback Database explicitly enabled

if desired. Real Time Query being active on a physical standby does not directly relate to the ability to

execute this command on the standby. Reference: The explanation is based on Oracle's concepts for

Flashback Technology and Data Guard configurations as detailed in the Oracle Database Backup and

Recovery User's Guide and the Oracle Data Guard Concepts and Administration guide.

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In an Oracle Active Data Guard environment:

B: Read-mostly reporting applications that utilize global temporary tables to store session-specific

data can be effectively offloaded to an Active Data Guard standby database, reducing the load on the

primary database.

C: Sequences can be used with global temporary tables on an Active Data Guard standby database to

support certain types of read-mostly applications, though some restrictions on sequence use may

apply.

E: In Oracle Database 19c and later, DML redirection allows DML operations performed on an Active

Data Guard standby database to be transparently redirected to the primary database. This is part of

the DML Redirection feature.

Option A is incorrect because not all PL/SQL blocks run on an Active Data Guard standby database

can be redirected to the primary database. Some PL/SQL executions, specifically those that would

attempt to make changes to the database, are not supported on the standby.

Option D is incorrect because DDL operations on private temporary tables are not redirected;

instead, private temporary tables are session-specific and are not persisted on disk, so they do not

generate redo and are not applicable to an Active Data Guard standby.

Reference: The behavior and capabilities of Active Data Guard standby databases are documented in

the Oracle Data Guard Concepts and Administration guide and the Active Data Guard documentation.

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A static service must be registered with the local listener to enable DGMGRL to restart instances

during the course of broker operations (A): For DGMGRL (Data Guard Manager Command-Line

Interface) to perform instance management operations, such as restarting instances, a static service

registration in the listener is required. This allows the broker to connect to the database instance

even when the instance is not fully up and the dynamic service registration is not available.

Installing the oracle-database-preinstall-19c package is NOT sufficient to set up operating system

kernel parameters for Oracle Net (C): While the oracle-database-preinstall-19c package automates

the setting of several kernel parameters to meet the preinstallation requirements for Oracle

Database, it does not specifically tailor all settings for Oracle Net in a Data Guard configuration.

Additional manual configuration may be required to optimize Oracle Net services for Data Guard

operations.

Reference:

Oracle Data Guard Broker documentation

Oracle Net Services Administrator's Guide

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The command executed (CREATE CONFIGURATION 'DGConfig' AS PRIMARY DATABASE IS 'PROD'

CONNECT IDENTIFIER IS PROD;) is used to create a Data Guard Broker configuration named

'DGConfig'. The successful execution of this command depends on several conditions:

A: The DG_BROKER_START parameter must be set to TRUE on the primary database to start the Data

Guard Broker processes. Without the broker processes running, the configuration cannot be created.

D: Oracle Net connectivity to the PROD database instance must be established on the primary host.

This is because the Data Guard Broker requires network accessibility to communicate with the

primary database and manage the configuration.

E: When the configuration is created, the Data Guard Broker configuration files are indeed

automatically created in the locations specified by the DG_BROKER_CONFIG_FILEn parameters on

the primary database.

It's important to note that the command will not automatically add the PRODSBY1 standby database

to the configuration (thus B and C are not correct), and there is no requirement for the standby

database to have Oracle Net connectivity defined on the primary host for the execution of this

command (making F incorrect as well).

Reference: This information can be validated in Oracle's Data Guard Broker documentation, which

outlines the requirements for setting up and managing a Data Guard configuration using the Data

Guard Broker.

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.

Reference

Oracle documentation on Data Guard configurations and the V$DATABASE view which provides

information about the fast-start failover status and observer host.