[Mar-2026] 1Z0-084 Dumps Full Questions – Oracle Database 19c Exam Study Guide [Q19-Q35]

Given that index range scan operations onIX_SALES_TIME_IDare slower due to an increase in buffer gets, the aim is to improve the efficiency of the index access. In this scenario:
* B (Correct):Re-creating the index usingADVANCED COMPRESSIONcan reduce the size of the index, which can lead to fewer physical reads (reduced I/O) and buffer gets when the index is accessed, as more of the index can fit into memory.
The other options would not be appropriate because:
* A (Incorrect):Re-creating theSALEStable sorted in order of the index might not address the issue of excessive buffer gets. Sorting the table would not improve the efficiency of the index itself.
* C (Incorrect):Using the columns inIX_SALES_TIME_IDas a hash partitioning key for theSALES table is more relevant to data distribution and does not necessarily improve index scan performance.
* D (Incorrect):Hash partitioning the index is generally used to improve the scan performance in a parallel query environment, but it may not reduce the number of buffer gets in a single-threaded query environment.
References:
* Oracle Database SQL Tuning Guide:Managing Indexes
* Oracle Database SQL Tuning Guide:Index Compression

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.
References:
* Oracle Database Error Messages, 19c
* Oracle Database Administrator’s Guide, 19c

The Oracle Optimizer statistics advisor, which is part of the automated tasks framework, can be disabled using the DBMS_AUTO_TASK_ADMIN package. This will prevent it fromrunning and thus reduce space usage in the SYSAUX tablespace.References:
* Oracle Database PL/SQL Packages and Types Reference, 19c

The SQL Query Result Cache stores the results of queries and PL/SQL function calls for reuse. However, entries in the result cache can be invalidated or lost under certain conditions:
A: Results can be aged out of the cache when the cache becomes full and new results need to be stored. This process ensures that the cache does not exceed its allocated memory and that it contains the most recently used entries.
B: Setting theRESULT_CACHE_MAX_SIZEparameter to 0 will effectively disable the result cache and all cached results will be lost, as Oracle will no longer allocate any memory to the result cache.
References:
* Oracle Database Performance Tuning Guide, 19c

Monitoring of Database Operations requires that theSTATISTICS_LEVELparameter be set toALLand CONTROL_MANAGEMENT_PACK_ACCESSbe set toDIAGNOSTIC+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.
References:
* Oracle Database Reference:STATISTICS_LEVEL
* Oracle Database Licensing Information User Manual:Oracle Database Management Packs

The DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATE procedure is used to create a repeating baseline template in the Automatic Workload Repository (AWR). This template will generate baselines for a specified duration of time on a repeating schedule. The parameters of the CREATE_BASELINE_TEMPLATE procedure include the start and end times, as well as the day of the week and hour in the day when the baseline should be captured.
Given that the command specifies a repeating baseline every Monday at 5 PM with a duration of 3 hours and it expires after 30 days, the number of baselines generated by this command that you can have at any given time depends on how many Mondays fall within the most recent 30-day period.
Since the maximum number of Mondays that can occur within any 30-day period is 5 (four to five weeks), but considering the baseline has a duration of 3 hours and starts every Monday at 5 PM, only one baseline for each Monday can exist at a time. However, since baselines are preserved for 30 days, you could have multiple instances of Monday baselines preserved at a time.
* A (Incorrect): There can be more than one baseline at a time because the template will generate a baseline for every Monday during the 30-day expiration period.
* B (Incorrect): There will be more than three baselines because the template creates a baseline for every Monday within the 30-day expiration period.
* C (Correct): Over a 30-day period, considering the duration of the baselines and their frequency, you could have up to a maximum of 52 baselines if you consider the entire year.
* D (Incorrect): There is no option that restricts the number of baselines to 5 specifically, the answer relies on the calculation of how many baselines can exist over a period of time considering their expiration.
References:
* Oracle Database PL/SQL Packages and Types Reference: DBMS_WORKLOAD_REPOSITORY

To investigate the cause of the ORA-04036 error, which indicates that PGA memory usage exceeds the PGA_AGGREGATE_LIMIT, the appropriate views to consult are DBA_HIST_ACTIVE_SESS_HISTORY and DBA_HIST_PROCESS_MEM_SUMMARY.
* DBA_HIST_ACTIVE_SESS_HISTORY: This view provides historical information about active sessions in the database. It includes details about the SQL executed, the execution context, and the resources consumed by each session. By examining this view, you can identify the specific sessions and SQL queries that were active and potentially consuming excessive PGA memory around the time the ORA-04036 error occurred.
* DBA_HIST_PROCESS_MEM_SUMMARY: This view contains historical summaries of memory usage by processes. It can help in identifying the processes that were consuming a significant amount of PGA memory, leading to the ORA-04036 error. This view provides aggregated memory usage information over time, making it easier to pinpoint the processes responsible for high PGA memory consumption.
Together, these views offer a comprehensive overview of the memory usage patterns and specific queries or processes that might have contributed to exceeding the PGA_AGGREGATE_LIMIT, resulting in the ORA-
04036 error.
References:
* Oracle Database Reference: DBA_HIST_ACTIVE_SESS_HISTORY
* Oracle Database Reference: DBA_HIST_PROCESS_MEM_SUMMARY
* Oracle Database Performance Tuning Guide: Managing Memory

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

Regarding space usage in temporary tablespaces, the following statements are true:
* A (Correct): When a global temporary table or a sort operation exceeds the available memory, Oracle Database allocates space in a temporary tablespace to store the temporary data or intermediate results.
* E (Correct): Using temporary tablespace groups can prevent insufficient temporary tablespace for sort operations by providing a collective pool of space from multiple temporary tablespaces, which can be used for user sorting operations.
The other options provided have inaccuracies:
* B (Incorrect): Oracle does not provide a mechanism for setting quotas on temporary tablespaces.
Quotas can be set for permanent tablespaces but not for temporary ones.
* C (Incorrect): A sort operation may fail due to insufficient space, but Oracle will attempt to allocate space in the temporary tablespace dynamically. If no space can be allocated, an error is returned rather than a sort failure.
* D (Incorrect): If a session consumes all available temporary tablespace storage, Oracle will not hang the session; it will return an error to the session indicating that it has run out of temporary space.
References:
* Oracle Database Administrator’s Guide: Managing Space for Schema Objects
* Oracle Database Concepts: Temporary Tablespaces

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.
References
* Oracle Database 19c Performance Tuning Guide – Buffer Cache Hit Ratio
* Oracle Database 19c Performance Tuning Guide – v$db_cache_advice

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.
References:
* Oracle Database Error Messages, 19c
* Oracle Database Administrator’s Guide, 19c

What is a Soft Parse?
A Soft Parse occurs when a SQL statement is already present in the shared SQL area (Shared Pool) of the database. Instead of recreating the execution plan, Oracle reuses the existing plan, making the process much faster and more efficient. This is an essential optimization step in Oracle Database to reduce overhead and improve performance.
Steps Involved in a Soft Parse
* Syntax Check (Step A)
* This is the first step of the parsing process.
* Purpose: Ensures the SQL statement conforms to proper syntax rules defined by the SQL language.
* Example:
SELECT FROM employees;
This query will fail at the Syntax Check step because it doesn’t specify any columns to retrieve. Oracle ensures that such malformed queries are identified early.
* Semantic Check (Step E)
* The Semantic Check happens after the Syntax Check if the statement passes the syntax validation.
* Purpose:
* Verify Object Existence: Check if all referenced tables, columns, and other database objects exist. Example:
SELECT salary FROM non_existent_table;
This query will fail because the table non_existent_table does not exist.
* User Privileges: Ensure the user has sufficient permissions to access the objects. Example:
SELECT * FROM employees;
If the user doesn’t have SELECT privileges on the employees table, the query will fail.
* Validate Data Types: Ensure that columns used in expressions or comparisons are compatible in terms of data types. Example:
SELECT * FROM employees WHERE hire_date = ’01-01-2023′;
If hire_date is stored as a DATE type, and the literal is not implicitly convertible, this will fail.
Steps Skipped in a Soft Parse
SQL Row Source Generation (Option B):
This step involves breaking the query into operations (row sources) to fetch data. It is part of execution plan generation, which happens only during a Hard Parse.
SQL Optimization (Option C):
The SQL Optimizer calculates the most efficient execution plan during a hard parse. In a soft parse, the existing plan is reused, so this step is skipped.
Shared Pool Memory Allocation (Option D):
A Hard Parse allocates memory in the shared pool for a new SQL statement. In a soft parse, Oracle reuses the existing shared memory, avoiding additional allocation.
Why Are Syntax Check and Semantic Check the Correct Steps?
These steps are mandatory validations for all SQL statements, even during a soft parse. Without them, Oracle would risk executing invalid or unauthorized SQL statements.
By reusing the execution plan but performing these lightweight checks, Oracle ensures both efficiency and correctness.
References to Oracle Database 19c: Performance Management and Tuning
Oracle Documentation:
Oracle Database 19c Concepts: SQL Parsing and Execution
Oracle Database Performance Tuning Guide: Understanding Hard Parses and Soft Parses Key Features Discussed in the Guide:
Shared Pool and Library Cache: The role of the shared SQL area in reducing parsing overhead.
SQL Execution Workflow: Detailed explanation of syntax and semantic checks.
SQL Optimizer: The differences between hard and soft parsing in relation to the optimizer.
Tools for Analysis:
AWR Reports: Monitor the number of hard vs. soft parses for query performance.
V$SQL: View cached SQL statements and their parsing statistics.

The SQL Tuning Advisor provides recommendations for improving SQL query performance. This may include suggestions for creating additional indexes to speed up data retrieval and materialized views to precompute and store query results.References:
* Oracle Database SQL Tuning 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.References:
* Oracle Database Concepts, 19c
* Oracle Database SQL Tuning Guide, 19c

To reduce the number of hard parses due to several almost identical SQL statements, you can take the following actions:
* C (Correct):Increasing the size of the library cache can help reduce hard parses by providing more
* memory to store more execution plans. This allows SQL statements to be shared more effectively.
* E (Correct):Setting theCURSOR_SHARINGparameter toFORCEwill cause Oracle to replace literals in SQL statements with bind variables, which can significantly reduce the number of hard parses by making it more likely that similar SQL statements will share the same execution plan.
The other options do not directly impact the number of hard parses:
* A (Incorrect):Creating the KEEP cache and caching tables accessed by the SQL statements can improve performance for those tables, but it does not directly reduce the number of hard parses.
* B (Incorrect):Creating the RECYCLE cache and caching tables accessed by the SQL statements can make it more likely that objects will be removed from the cache quickly, which does not help with hard parse issues.
* D (Incorrect):SettingOPTIMIZER_CAPTURE_SQL_PLAN_BASELINEStoTRUEcan help stabilize SQL execution plans but will not reduce the number of hard parses. This parameter is used to automatically capture SQL plan baselines for repeatable SQL statements, which can prevent performance regressions due to plan changes.
References:
* Oracle Database Performance Tuning Guide:Minimizing Hard Parses
* Oracle Database SQL Tuning Guide:CURSOR_SHARING

Big Table caching is a feature that allows frequently accessed large tables to be cached in memory to improve I/O performance. From the parameter settings provided, Big Table caching is not occurring because DB_BIG_TABLE_CACHE_PERCENT_TARGET is set to 10, which is the minimum threshold for enabling the feature, but the size of the cache is too small for the big tables to be effectively cached.
To enable Big Table caching, one of the following actions could be taken:
* C (Correct): Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 25. This action would allocate a larger percentage of the buffer cache for storing big tables, which could allow for caching large tables and thus improve I/O performance.
* D (Correct): Increasing DB_CACHE_SIZE to 1G. Since the size of the buffer cache is a determining factor for how much data can be cached, increasing this parameter would provide more memory space for big tables to be cached.
Options A, B, E, and F will not enable Big Table caching because:
* A: Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to 50 without adjusting the overall size of the cache might still not be sufficient if the DB_CACHE_SIZE is not large enough to hold the big tables.
* B: Setting DB_KEEP_CACHE_SIZE to at least 50M only specifies a separate buffer pool for objects with the KEEP cache attribute and does not affect Big Table caching.
* E: and F: Changing the PARALLEL_DEGREE_POLICY to ADAPTIVE or AUTO influences the behavior of parallel execution but does not directly enable or influence Big Table caching.
References:
* Oracle Database Performance Tuning Guide: Big Table Caching
* Oracle Database Reference: DB_BIG_TABLE_CACHE_PERCENT_TARGET
* Oracle Database Reference: DB_CACHE_SIZE

In Oracle Database, theV$SESSION_LONGOPSview provides insights into various operations within the database that are expected to take more than six seconds to complete. These include operations related to RMAN (Recovery Manager), such as database duplication tasks. This view displays information about the progress of these long-running operations, including the start time, elapsed time, and estimated time to completion.
When an RMAN session is performing a database duplication and is observed to be slower than usual, checking theV$SESSION_LONGOPSview can give an approximation ofwhen the RMAN operation might complete. This view includes fields likeTIME_REMAININGandELAPSED_SECONDSthat help in estimating the completion time of the operation based on its current progress.
References:
* Oracle Database Reference:V$SESSION_LONGOPS
* Oracle Database Backup and Recovery User’s Guide:Monitoring RMAN Jobs