1Z0-084 Practice Questions

Monitoring of Database Operations requires that the STATISTICS_LEVEL parameter be set to ALL and

CONTROL_MANAGEMENT_PACK_ACCESS be set to DIAGNOSTIC+TUNING. These settings enable all

the advisory features and automatic tuning features within the Oracle Database, including the

Automatic Workload Repository (AWR), Automatic Database Diagnostic Monitor (ADDM), and the

full functionality of the SQL Tuning Advisor and SQL Access Advisor, which are components of the

Diagnostic and Tuning packs.

STATISTICS_LEVEL=ALL: This setting enables the collection of all system statistics for problem

detection and self-tuning purposes.

CONTROL_MANAGEMENT_PACK_ACCESS=DIAGNOSTIC+TUNING: This grants access to both the

Diagnostic Pack and the Tuning Pack, which are essential for detailed performance monitoring and

tuning capabilities.

Reference:

Oracle Database Reference: STATISTICS_LEVEL

Oracle Database Licensing Information User Manual: Oracle Database Management Packs

When you execute DBMS_AUTO_TASK_ADMIN.DISABLE, it disables all automated maintenance tasks

related to the Auto Task framework. This includes tasks such as the Automatic SQL Tuning Advisor,

Automatic Segment Advisor, and others. However, the Automatic Optimizer Statistics Collection (D)

remains enabled as it is not part of the Auto Task framework. The gathering of optimizer statistics is

controlled separately and is a critical part of the database's self-tuning mechanism to ensure the

optimizer has up-to-date information about the data distribution within tables and indexes.

Reference

Oracle Database 19c PL/SQL Packages and Types Reference - DBMS_AUTO_TASK_ADMIN

Oracle Database 19c Database Administrator’s Guide - Managing Optimizer Statistics

To produce a consolidated formatted trace file from multiple trace files generated by all clients for a

single service, the combination of trcsess and TKPROF utilities is used. The trcsess utility consolidates

trace files based on specified criteria such as session, client identifier, or service name. This results in

a single trace file that combines the desired tracing information. Next, TKPROF is used to format the

output of the trace file generated by trcsess, providing a readable summary of the trace, including

execution counts, execution times, and SQL statement text along with execution plans.

Steps:

Use trcsess to combine trace files:

Command: trcsess output=consolidated.trc service=your_service_name *.trc

Use TKPROF to format the consolidated trace file:

Command: tkprof consolidated.trc output.txt explain=user/password sys=no sort=prsela,fchela

Reference:

Oracle Database Performance Tuning Guide, 19c

Oracle Database Utilities, 19c

The DBMS_STATS.GATHER_DATABASE_STATS procedure is used to gather statistics for all schema

objects in the database that do not have up-to-date statistics. These statistics are essential for the

optimizer to make informed decisions about the most efficient way to execute a query. The

procedure collects statistics such as table and column statistics, index statistics, and system statistics,

which are all used in the execution plan generation.

Reference:

Oracle Database PL/SQL Packages and Types Reference, 19c

Oracle Database Performance Tuning Guide, 19c

A high buffer cache hit ratio typically indicates that the database is effectively using the buffer cache and does not often need to read data from disk. However, this metric alone is not a reliable indicator of the I/O performance of the database for several reasons: Full table scans and fast full index scans (A) can bypass the buffer cache by design if the blocks are not deemed reusable shortly, which can impact the cache hit ratio. A high cache hit ratio (B) can be misleading if the database performance is poor due to other factors, such as inefficient queries or contention issues. The buffer cache advisory (C) is a more valuable tool for understanding the potential impact of different cache sizes on the database's I/O performance. It simulates scenarios with different cache sizes and provides a more targeted recommendation. The RECYCLE and KEEP buffer caches (D) are specialized caches designed for certain scenarios. While high hit ratios can be beneficial, they are not universally required; some workloads might not be significantly impacted by lower hit ratios in these caches. A lower cache hit ratio (E) does not necessarily mean poor I/O performance. In some cases, a system with a well-designed storage subsystem and efficient queries might perform well even with a lower cache hit ratio. Reference Oracle Database 19c Performance Tuning Guide - Buffer Cache Hit Ratio Oracle Database 19c Performance Tuning Guide - v$db_cache_advice

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. Reference: 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

A) When Cursor_sharing is set to FORCE, Oracle tries to avoid hard parses by replacing literals in SQL statements with bind variables, even if the original statement didn't include bind variables. This can lead to the use of a single execution plan for multiple executions of a statement with different literal values, which might not be optimal for all executions. D) Setting cursor_sharing to EXACT ensures that SQL statements must match exactly for them to share a cursor. This setting prevents the use of Adaptive Cursor Sharing (ACS) since ACS relies on the ability to share cursors among similar statements that differ only in their literal values. With EXACT, there's no cursor sharing for statements with different literals, hence no opportunity for ACS to operate. Reference: Oracle Database SQL Tuning Guide, 19c Oracle Database Reference, 19c

The ORA-15505 error indicates that the instance encountered errors while trying to access the specified directory. This could be due to: A) Insufficient privileges: The user attempting to start the workload capture might not have the required permissions to execute the DBMS_WORKLOAD_CAPTURE package or to read/write to the directory specified. E) Accessibility: The database instance may not be able to access the directory due to issues such as incorrect directory path, directory does not exist, permission issues at the OS level, or the directory being on a file system that's not accessible to the database instance. Reference: Oracle Database Error Messages, 19c Oracle Database Administrator’s Guide, 19c

During a soft parse, Oracle checks the shared SQL area to see if an incoming SQL statement matches

one already in the shared pool. This operation includes syntax and semantic checks. The syntax check

ensures the statement is properly formed, and the semantic check confirms that all the objects

referenced in the SQL statement exist and that the user has the necessary privileges to access them.

Reference:

Oracle Database Concepts, 19c

Oracle Database SQL Tuning Guide, 19c

Server-generated alerts in Oracle Database are designed to notify DBAs and other administrators about issues within the database environment. These alerts can be triggered by a variety of conditions, including threshold-based metrics and specific events such as ORA- error messages. Here's how these options align with the statements provided: A (True): Server-generated alerts are indeed notifications from the Oracle Database Server that highlight existing or impending issues. These alerts are part of Oracle's proactive management capabilities, designed to inform administrators about potential problems before they escalate. C (True): These alerts are logged in the alert log of the Oracle Database. The alert log is a crucial diagnostic tool that records major events and changes in the database, including server-generated alerts. This log is often the first place DBAs look when troubleshooting database issues. F (True): Server-generated alerts may include suggestions for correcting identified problems. Oracle Database often provides actionable advice within these alerts to assist in resolving issues more efficiently. These suggestions can range from adjusting configuration parameters to performing specific maintenance tasks. Options B, D, and E do not accurately describe server-generated alerts: B (False): While the statement might have been true in some contexts, Oracle's server-generated alerts often include corrective suggestions, making this statement incorrect. D (False): Server-generated alerts can be viewed from various interfaces, not just the Cloud Control Database home page. They are accessible through Enterprise Manager, SQL Developer, and directly within the database alert log, among other tools. E (False): While it's true that threshold settings for some alerts can be modified, the method specified, using DBMS_SERVER_ALERT, is not correct. Threshold settings are typically adjusted through Enterprise Manager or by modifying specific initialization parameters directly. Reference: Oracle Database Documentation: Oracle Database 19c: Performance Management and Tuning Oracle Base: Alert Log and Trace Files Oracle Support: Understanding and Managing Server-Generated Alerts