Pass the Oracle Database 19c 1z0-076 Questions and answers with ExamsMirror

The DBMS_ROLLING package facilitates a rolling upgrade process across a Data Guard configuration. The START PLAN procedure in particular handles several critical actions, including:

Creating a guaranteed restore point on the standby databases (B):This ensures that the standby databases can be reverted to their state before the rolling upgrade process in case of any issues.

Building a LogMiner dictionary on the primary database instance (C):This is necessary for logical standby databases to interpret redo data during the SQL Apply process.

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 Far Sync instance is a special kind of Oracle Data Guard configuration that allows synchronous redo transport from a primary database to a remote standby database with minimum impact on the primary database's performance. The Far Sync instance receives redo data synchronously from the primary database (A), then ships it asynchronously to the remote standby database, thus extending zero data loss protection over longer distances and higher network latency environments than would be practical with a synchronous standby alone. The Far Sync instance does not apply the redo data; it just receives and ships it (E). A Far Sync instance does not have data files, and it cannot apply redo to stay synchronized with the primary database.

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.

In Oracle, a sequence created with theGLOBALkeyword is available and can produce values across all sessions and instances. However, a sequence created with theSESSIONkeyword is only specific to the session it was created in. When theNEXTVALis called for a sequence, it will increment according to the sequence's properties set during its creation.

Given the sequence creation statements and the actions performed:

Theasequence is global, which means it is available across the entire database, including the standby database with Real-Time Query enabled. So, when session 2 callsa.nextval, it will get the next value in the sequence, which is 21 since session 1 already retrieved 1.

Thebsequence is session-specific, so when session 2 callsb.nextval, it will get the value 1 because for this new session on the standby, this is the first time the sequence is being accessed.

Therefore, the output for session 2 will beaoutput as 21 andboutput as 1, which corresponds to Option C.

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.

Data Guard Broker is a management tool that simplifies the configuration, management, and monitoring of Data Guard environments. The prerequisites for using Data Guard Broker include:

The primary and standby databases must run the same version of the Oracle Database server (A):This ensures compatibility between the primary and standby databases and enables seamless role transitions and data synchronization.

Network connectivity to the primary database instance must be defined on the servers hosting the standby database instances (B):Proper network connectivity is essential for communication between the primary and standby databases, allowing for the replication of data and the synchronization of changes.

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.

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.