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

After a successful switchover operation in a Data Guard environment, the new primary database (the former standby) will be open read-write (option A). If the former primary database transitions to a logical standby database, it will also be open read-write (option C), allowing it to apply redo data while servicing read-only queries. The former primary, if converted to a physical standby, will adopt the state that the former physical standby database was in prior to the switchover, which can vary based on the configuration prior to the switchover (option D). The state of a physical standby database can range from mounted to open read-only, depending on whether Real-Time Query was enabled. Thus, the exact state will depend on the pre-switchover setup. It's also essential to highlight that options B and E suggest specific states for a former primary turned logical standby, and a former primary turned physical standby, respectively, but these states are not fixed and depend on the configurations set up by the database administrators. References: The answers are corroborated by Oracle's documentation on Data Guard switchovers, specifically in the Oracle Data Guard Concepts and Administration guide, which explains the roles and states of databases in a Data Guard configuration before and after switchovers.

The ORA-03172: STANDBY_MAX_DATA_DELAY error indicates that the real-time query on the physical standby database is experiencing delays beyond the specified maximum data delay threshold. Increasing the network bandwidth (Option E) can enhance the speed at which redo data is transferred from the primary to the standby database, thereby reducing the likelihood of exceeding the STANDBY_MAX_DATA_DELAY threshold. Reducing I/O latency on the primary database's storage (Option B) ensures that redo data is generated and shipped more efficiently, further mitigating the risk of delay. These actions, focused on optimizing data transfer and processing speed, address the root causes of the ORA-03172 error in a synchronous Data Guard configuration operating in Maximum Availability mode.

When a physical standby database is opened in real-time query mode, which may be referred to as real-time apply when using Active Data Guard, certain operations can disrupt ongoing sessions. However, with features like Application Continuity and the proper configuration of initialization parameters such as STANDBY_DB_PRESERVE_STATES, user sessions and current buffers may be preserved during role transitions such as a switchover or failover. Specifically, the STANDBY_DB_PRESERVE_STATES parameter can be set to preserve none, all, or only user sessions during such transitions. This ensures that in-flight transactions are not lost and that users do not experience disruptions during the role transitions of a physical standby database​​​​.

References

• Oracle Data Guard Concepts and Administration​​
• Oracle Database Licensing Information User Manual​​
• Oracle Data Guard Broker User Manual​

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.
• Flashback Database must be enabled on both the primary database and the Fast-Start Failover target standby database (F): Flashback Database provides a quick way to revert a database to a point in time before a logical or physical corruption or error occurred. It must be enabled on both the primary and target standby databases to allow for the possibility of reinstating the old primary as a standby after a failover.References:
• Oracle Data Guard Concepts and Administration Guide
• Oracle Database High Availability Overview

• Logical standby databases allow the execution of DDL and DML operations, which makes them suitable for maintaining bitmap indexes and materialized views without affecting the performance of the primary database .
• Logical standby databases can be used for performing rolling upgrades and patching with minimum downtime, meeting another requirement .
• They also enable the testing of new application software releases against an up-to-date replica of the primary database, fulfilling the last requirement.

Other configurations involving physical standby databases or combinations of logical and physical standby databases might not meet all the specified requirements as efficiently or with the same level of performance isolation for the primary database.