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.
Reference:
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.

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.
References:Oracle Data Guard documentation clearly outlines the requirements and restrictions of different protection modes, including the necessity for standby databases to participate in synchronous redo transport to enable Maximum Protection mode. The inability of snapshot standby databases to fulfill this requirement is a key consideration when planning Data Guard configurations and protection levels.

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).

The DBMS_COMPARISON package, used for comparing and converging data objects within a single database or between databases, requires that the databases involved in the block comparison be at least mounted (A). This allows the procedure to access the data blocks for comparison. Additionally, the progress of long-running operations such as block comparison can be monitored using the dynamic performance view V$SESSION_LONGOPS (D), which provides information on the operation's progress and estimated completion time.
References:Oracle Database PL/SQL Packages and Types Reference provides comprehensive details on the DBMS_COMPARISON package, including its procedures and how to monitor their progress. Additionally, Oracle Database Reference explains the V$SESSION_LONGOPS view, which is commonly used for monitoring long operations in the database.