Oracle 1Z0-076 Exam Dumps

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 the CACHE size 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 the NOORDER and CACHE options set. The NOORDER option ensures that sequence numbers are provided without guaranteeing sequence order, thus improving scalability and performance. The CACHE option is used to specify how many sequence values will be held in memory for faster access.

Option B is incorrect as the LOG_ARCHIVE_DEST_n parameter'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. The CACHE size can be set to a different number based on specific use cases or performance considerations.

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.

Startup nomount the standby database instance (C): The standby database instance needs to be started in the NOMOUNT stage before the duplication can begin. This prepares the environment for creating the control file and restoring the database without mounting it, which is a necessary step in the RMAN duplication process. Reference:

Oracle Database Backup and Recovery User's Guide

Oracle Data Guard Concepts and Administration

A snapshot standby database is a fully updateable standby database that is created by converting a physical standby database into a snapshot standby database. The main characteristics of a snapshot standby database include:

B: Tablespaces can indeed be dropped in a snapshot standby database because it is updateable and allows all types of DML and DDL operations that do not conflict with the standby role.

C: Tablespaces can be created in a snapshot standby database for the same reasons that they can be dropped; it supports all operations that do not interfere with its standby nature.

E: Tables can be dropped in a snapshot standby database, as it is a fully updateable standby.

Options A and D are incorrect because 'FAILOVER TO' and 'SWITCHOVER TO' commands are not used with snapshot standby databases in these contexts. A failover converts a standby database into the primary role after the original primary has become unavailable, and is not a reversible role transition. Switchover is a planned role reversal between the primary database and one of its standby databases and is not applicable to snapshot standby databases in the context provided.

Option F is incorrect because a logical standby database cannot be converted into a snapshot standby database directly. A logical standby is used for different purposes such as reporting and querying with real-time data, and its structure is different from a physical standby which can be converted into a snapshot standby.