Authentic Oracle Certification Exam 1z0-084 Questions Answers

SQL Performance Analyzer (SPA) can be used to assess the impact of different types of changes on SQL performance. These changes can include database initialization parameters, which can significantly affect how SQL statements are executed and therefore their performance. SPA allows you to capture a workload before and after the change and compare the performance of each SQL statement.

Database consolidation, including moving to pluggable databases (PDBs), can also affect SQL performance. SPA can analyze the SQL workload to see how consolidation impacts performance, by comparing metrics such as elapsed time and CPU time before and after the consolidation.

References:

• Oracle Database SQL Tuning Guide, 19c
• Oracle Database Performance Tuning Guide, 19c

Database services in Oracle are used to manage how resources are allocated and how workloads are managed within the database. The features that use database services are:

• B (Correct):Database Resource Manager (DBRM) uses services to control resource allocation to different workloads. It ensures that resources are assigned to the most critical tasks first, based on the service associated with the workload.
• E (Correct):Oracle Scheduler can also utilize database services. Jobs in Oracle Scheduler can be assigned to different services to control resource allocation and prioritization.

The other features mentioned are related to SQL performance but do not directly utilize database services in the way Resource Manager and Scheduler do:

• A:Oracle Automatic Reoptimization is a feature that allows the database to automatically improve the execution plan of a SQL statement after it is executed, based on the actual performance metrics, but it does not directly use database services.
• C:Oracle SQL Performance Management involves various components of SQL tuning and monitoring, but it does not use database services to operate.
• D:Oracle SQL Tuning Advisor provides advice on how to tune SQL queries for better performance. While it can be used in conjunction with services for managing and analyzing workloads, it doesn't use services in its core functionality.

References:

• Oracle Database Administrator’s Guide:Administering Services
• Oracle Database Administrator's Guide:Managing Resources with Oracle Database Resource Manager
• Oracle Database Scheduler Developer’s Guide:Using the Scheduler

Given a server with 64 CPUs, if the buffer cache size increase did not alleviate free buffer waits and buffer busy waits, one can look into optimizing I/O and the efficiency of the DB writer processes.

C. Setting theDBWR_IO_SLAVESparameter to a non-zero value, such as the number of CPUs, would initiate I/O slave processes to assist the DB writer process. This can help reduce I/O contention when writing from the buffer cache to disk, particularly for systems without asynchronous I/O capabilities.

D. Increasing the value ofDBWRITERPROCESSESenables multiple DB writer processes to be active simultaneously. In a system with many CPUs, such as 64, increasing this value can improve the write throughput to disk and potentially reduce buffer busy waits.

References:

• Oracle Database Reference, 19c
• Oracle Database Performance Tuning Guide, 19c