Oracle 1z0-076 Oracle Database 19c: Data Guard Administration Exam Practice Test

Creating a physical standby database using RMAN active database duplication requires certain prerequisites to ensure a successful and seamless operation:

Configure Oracle Net connectivity on the primary host to the standby database instance (A):Proper Oracle Net connectivity between the primary and standby servers is essential for communication and data transfer during the duplication process. Oracle Net services provide the network foundation for Oracle Database, Oracle Net Listener, and Oracle applications.

Establish user equivalence for the database software owner between the primary host and standby host (B):User equivalence ensures that the user who owns the Oracle Database software on the primary server has the same privileges on the standby server. This is crucial for RMAN to perform operations on both servers without encountering permission issues.

The Data Guard Monitor (DMON) process is a key component of Oracle Data Guard. It plays a crucial role in managing and monitoring the state of both the primary and standby databases in a Data Guard configuration.

Performing role transitions when switchover requests are made (A):DMON is responsible for coordinating the switchover process between the primary and standby databases. This involves safely transitioning the roles of the databases to ensure data protection and availability.

Maintaining information about all members of the broker configuration in binary configuration files (B):DMON maintains detailed information about the databases in the Data Guard configuration, including their roles, states, and network addresses. This information is stored in binary configuration files, which are used by the Data Guard Broker to manage the Data Guard environment.

Oracle Multi-tenant architecture and Data Guard have several interactions, but specific aspects hold true in such environments:

The Data Guard broker may be used for multi-tenant databases (B):Data Guard Broker simplifies the management and monitoring of Data Guard configurations and is fully compatible with the Oracle Multi-tenant architecture, allowing for easy management of Data Guard configurations that include multi-tenant container databases (CDBs) and their pluggable databases (PDBs).

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

ThefastStartFailoverTargetproperty is not set onDogs(A):The primary database (Dogs) needs to have a fast-start failover target configured for the operation to succeed.

TheLogXptModeproperty is set toASYNConSheepwhileSheepis the target standby database (B):Fast-start failover requires synchronous redo transport (SYNCorFASTSYNC) to ensure zero data loss, which is a prerequisite for enabling the feature.

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.

Transaction Guard provides benefits in terms of transaction consistency and recovery in a Data Guard environment:

It provides application continuity by rolling back uncommitted transactions interrupted by a failover or switchover (B):Transaction Guard ensures that any uncommitted transactions at the time of an outage are rolled back consistently, thus preserving the integrity of the application's data and state.

When setting up a Data Guard Broker configuration for a primary database and its physical standby, the following prerequisites must be met:

A: Oracle Net connectivity must be defined on both the primary and standby hosts to enable the respective database instances to communicate with each other.

B: Supplemental logging is required on the primary database because it provides additional logging necessary for the standby database to be able to apply changes from the primary database accurately.

F: TheDG_BROKER_STARTparameter must be set toTRUEfor both the primary and standby database instances. This parameter is used to start the Data Guard Broker process which manages the configuration.

Options C and D are not prerequisites for creating a Data Guard Broker configuration. Additionally, while FORCE LOGGING mode (option E) is recommended as a best practice to prevent possible data inconsistencies during media recovery, it is not a strict prerequisite for creating a Data Guard Broker configuration.

C. The LGWR (Log Writer) process is responsible for writing redo entries from the redo log buffer to the online redo log files on the primary database. This is a fundamental process in the Oracle Database architecture, ensuring that all changes made to the database are captured for purposes such as recovery, replication, and high availability.

D. Real-time apply on a logical standby database requires standby redo log files. The standby redo log files are used to store redo data received from the primary database before it is applied to the logical standby database. This enables the logical standby to apply changes as they are received, without waiting for the current redo log file to be archived.

E. Similarly, on a physical standby database, standby redo log files are used for real-time apply. They store redo data from the primary database, allowing the physical standby to apply redo data concurrently as it is received, rather than waiting for redo log files to be archived. This capability is crucial for maintaining a physical standby database that is closely synchronized with the primary database with minimal lag.

These functionalities are integral to Oracle Data Guard configurations and are not dependent on Oracle Streams or Oracle GoldenGate, which are separate technologies for data replication and integration​​​​.

For seamless client redirection in a Data Guard environment, the following steps should be taken:

Create a database service on the primary database that is started automatically by a trigger when the database role is PRIMARY (B):This ensures that the service is only available on the primary database and is automatically started after a role transition due to switchover or failover.

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.

To enable Fast-Start Failover in a Data Guard environment, the following conditions must be in place:

The Data Guard environment must be managed by the Data Guard Broker (A):The Broker simplifies management tasks and is required to enable fast-start failover, which is an automatic failover mechanism provided by Data Guard.

You can specify only one standby database as the fast-start failover target (C):Fast-start failover is designed to fail over to a single, predetermined standby database, known as the target standby.

The error indicates that switching the protection mode to Maximum Protection is not possible due to the presence of a snapshot standby database in the Data Guard configuration, which cannot participate in synchronous redo transport required by the Maximum Protection mode. Therefore, the correct answer is:

D. Cats is a snapshot standby database.

Comprehensive Detailed Explanation:

In an Oracle Data Guard environment, the Maximum Protection mode requires that all redo data be transmitted synchronously to at least one standby database, ensuring no data loss even in the event of a primary database failure. However, a snapshot standby database, by its nature, allows read-write access and is temporarily disconnected from the redo stream, which makes it unable to participate in the synchronous redo transport required by Maximum Protection mode. The presence of a snapshot standby database in the Data Guard configuration thus prevents the activation of Maximum Protection mode, as it cannot guarantee zero data loss without a standby database capable of receiving redo data synchronously.

A Physical Standby Database can indeed be converted into a Logical Standby Database, providing flexibility in a Data Guard configuration. This allows for the database to switch roles and supports SQL apply operations, enabling more granular control over the data and transactions being replicated and applied. Additionally, having a configuration with a primary database and one or more physical standby databases allows for rolling upgrades to be performed. This means that each database in the Data Guard configuration can be upgraded in a phased manner, minimizing downtime and ensuring high availability during the upgrade process​​​​.

Stop the Observer on host1 to ensure that there are no conflicts between the instances of the Observer running on different hosts.

Update the Data Guard Broker configuration with the new hostname for the Observer. This step is crucial to redirect the Data Guard Broker to communicate with the Observer on the new host.

Start the Observer on host2 to resume its operations in the new environment.

Disabling and re-enabling Fast-Start Failover (steps 2 and 4) are not strictly necessary for moving the Observer to a new host. These steps would be more relevant if changes to the configuration of Fast-Start Failover itself were required, which is not the case when simply relocating the Observer.

Snapshot standby databases are a feature of Oracle Data Guard that allows a physical standby database to be temporarily converted into a read-write database for testing or other purposes. The true statements about snapshot standby databases are:

FLASHBACK DATABASE is enabled automatically on a snapshot standby database after converting it from a physical standby database if not already enabled (B):When a physical standby is converted to a snapshot standby, FLASHBACK DATABASE is automatically enabled to allow the database to be easily reverted back to its original state.

FLASHBACK DATABASE is enabled automatically on a physical standby database as part of the conversion into a snapshot standby database, if not already enabled (C):As part of the conversion process, FLASHBACK DATABASE is turned on to ensure that changes made while the database is in snapshot standby mode can be undone.

A snapshot standby database may be opened read-write (E):Once a physical standby is converted to a snapshot standby, it can be opened for read-write operations, allowing for testing and other tasks that require a writable database.

The SQL apply lag on a logical standby database can be caused by several factors:

A: An undersized undo tablespace can lead to delays in SQL apply operations as it may not be able to handle the volume of undo records generated by the SQL apply process.

B: SQL apply operations that do full table scans can consume significant system resources, potentially leading to higher apply lag.

C: An increased number of bulk updates on the primary database may generate a large volume of redo data, which can cause apply lag if the logical standby cannot apply the changes quickly enough.

F: An undersized shared pool may affect the parsing and execution of SQL statements by SQL apply, which can contribute to the apply lag.

Option D is less likely to be a direct cause of SQL apply lag compared to bulk updates, as inserts generate new data rather than modifying existing data, which SQL apply can typically handle more efficiently.

Option E is incorrect because the size of the standby redo log files on the primary database impacts redo transport lag, not SQL apply lag.

To reduce the redo apply lag on standby databases, one could increase the size of the standby redo log files. Larger redo log files can accommodate more redo data, which may reduce the frequency of log switches and allow for more continuous application of redo data. Additionally, lowering theDB_BLOCK_CHECKINGparameter to MEDIUM or LOW on the standby databases can help improve redo apply performance. High block checking can impose additional CPU overhead during the application of redo data, potentially increasing apply lag times. By reducing the level of block checking, you can lessen this overhead and help reduce the apply lag ​​.

The commandALTER 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.References: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.

A fast recovery area must be configured (B):Flashback Database requires a fast recovery area to be set up because flashback logs are stored there. The fast recovery area is a unified storage location for all recovery-related files and activities.

The database must be in ARCHIVELOG mode (C):Flashback Database operation relies on the ability to archive redo logs. Therefore, the database must be running in ARCHIVELOG mode for Flashback Database to be enabled.

AWR collects, processes, and maintains performance statistics for problem detection and self-tuning purposes. In an Active Data Guard environment, where the physical standby database can be used for read-only workloads, AWR can be instrumental in identifying performance bottlenecks and areas for optimization. It provides detailed reports that include wait events, time model statistics, and active session history, making it an invaluable tool for tuning SQL queries and overall database performance in an ADG setup.

Block change tracking is a feature that enhances the efficiency of incremental backups by recording changed blocks in a tracking file. When used with Oracle Active Data Guard:

It starts the RVWR process on the physical standby database instance (A):When block change tracking is enabled on a physical standby database, the Recovery Writer (RVWR) process is initiated. This process is responsible for recording the changes to blocks in the block change tracking file, which is then used to optimize incremental backups.

Global Sequences are Oracle sequences that generate unique values across multiple instances in an Oracle RAC or a Data Guard configuration. Regarding their behavior and performance when connected to a physical standby database with Real-Time Query enabled:

A: The usage of Global Sequences can indeed have a performance impact on the primary database due to the need to generate unique values that are consistent across both primary and standby databases.

D: The performance impact on the physical standby database may occur if theCACHEsize is too small. This is because the standby database will frequently have to access the primary database to replenish the cache, which can increase the load and potentially lead to performance degradation.

E: Global Sequences should have theNOORDERandCACHEoptions set. TheNOORDERoption ensures that sequence numbers are provided without guaranteeing sequence order, thus improving scalability and performance. TheCACHEoption is used to specify how many sequence values will be held in memory for faster access.

Option B is incorrect as theLOG_ARCHIVE_DEST_nparameter's definition for standbys pointing back to the primary does not directly pertain to the creation of sequences.

Option C is incorrect because there is no requirement that the size of the cache for a sequence must be at least 100. TheCACHEsize can be set to a different number based on specific use cases or performance considerations.

Enterprise Manager Cloud Control offers comprehensive monitoring capabilities for Oracle Data Guard environments. It enables monitoring the rate at which redo is being applied on a logical standby database (A), which is crucial for ensuring that the standby database is keeping up with the changes from the primary. It also allows setting thresholds on performance metrics, such as the redo generation rate on the primary database (B), to alert administrators when values exceed critical or warning thresholds. Additionally, it provides the capability to estimate the potential data loss in the event of a disaster (E), helping in disaster recovery planning and ensuring business continuity.