Oracle 1Z0-084 Daily Practice Exam New 2025 Updated 57 Questions [Q18-Q38]

Oracle 1Z0-084 Daily Practice Exam New 2025 Updated 57 Questions

Use Valid 1Z0-084 Exam - Actual Exam Question & Answer

Oracle 1Z0-084 (Oracle Database 19c Performance and Tuning Management) Certification Exam is a professional certification exam offered by Oracle to validate the skills and knowledge of individuals in performance and tuning management of Oracle Database 19c. 1Z0-084 exam is designed for professionals who work with Oracle Database administrators, database developers, and other IT professionals who are responsible for the overall performance of an Oracle Database 19c environment. 1Z0-084 exam tests the candidate's knowledge on various topics like database architecture, SQL tuning, performance analysis, and performance tuning best practices.

Oracle 1Z0-084 certification exam is an essential certification for individuals who work with Oracle Database 19c. It tests their knowledge and skills in performance tuning and management, and earning this certification validates their expertise in this area. By passing 1Z0-084 exam, individuals can increase their career opportunities and demonstrate their proficiency in Oracle Database 19c performance and tuning management.

 

NEW QUESTION # 18
You want to reduce the amount of db file scattered read that is generated in the database.You execute the SQL Tuning Advisor against the relevant workload. Which two can be part of the expected result?

• A. recommendations regarding partitioning the tables
• B. recommendations regarding the creation of additional indexes
• C. recommendations regarding rewriting the SQL statements
• D. recommendations regarding the creation of materialized views
• E. recommendations regarding the creation of SQL Patches

Answer: B,D

Explanation:
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

NEW QUESTION # 19
What is the right time to stop tuning an Oracle database?

• A. When the tuning goal has been met
• B. When the buffer cache and library cache hit ratio is above 95%
• C. When the allocated budget for performance tuning has been exhausted
• D. When the I/O is less than 10% of the DB time
• E. When all the concurrency waits are eliminated from the Top 10

Answer: A

Explanation:
The objective of performance tuning in Oracle Database is to meet specific performance goals. These goals may vary based on the requirements of the system and business objectives. Let's evaluate each option in detail to understand why E is correct and others are not.
Option Analysis:
* A. When the allocated budget for performance tuning has been exhausted
* Why it's incorrect:
* Tuning should not stop simply because the budget is exhausted. If performance goals are not met, the database might still experience performance issues, impacting the end-users or business-critical processes. Budget is a constraint, but it shouldn't define when tuning stops.
* B. When all the concurrency waits are eliminated from the Top 10
* Why it's incorrect:
* Concurrency waits (such as locks or latches) are just one aspect of database performance tuning. Eliminating these waits does not necessarily mean the system meets its performance goals. Other factors like query optimization, I/O performance, and CPU usage might still need attention.
* C. When the buffer cache and library cache hit ratio is above 95%
* Why it's incorrect:
* Cache hit ratios are often overemphasized as a performance metric. While a high hit ratio indicates efficient memory usage, it doesn't guarantee optimal performance. A high ratio could still mask inefficient SQL queries, suboptimal execution plans, or other bottlenecks.
* D. When the I/O is less than 10% of the DB time
* Why it's incorrect:
* While reducing I/O is beneficial, it is not always a sufficient indicator that tuning can stop.
Certain workloads may inherently have high or low I/O percentages. The real question is whether the database is meeting its required service levels, not just reducing I/O.
* E. When the tuning goal has been met
* Why it's correct:
* The purpose of performance tuning is to meet the specific performance goals set by the business or the database administrators. Once the database meets these goals (e.g., query response times, throughput requirements, or SLA commitments), tuning can stop. This ensures effort is focused on achieving measurable outcomes, rather than chasing arbitrary metrics.
The Importance of Defining a Tuning Goal
Performance tuning should be driven by clear goals such as:
* Reducing response time for specific critical queries.
* Meeting SLAs for application performance.
* Supporting a target number of concurrent users.
* Reducing resource contention for improved scalability.
Tuning should stop once these goals are achieved because continuous tuning without purpose can lead to unnecessary complexity and resource usage.
Reference to Oracle Documentation:
* Oracle Database 19c Performance Tuning Guide:
* Section: Establishing Performance Goals and Metrics.
* Discussion on focusing tuning efforts on business requirements and goals.
* Oracle Database Concepts Guide:
* Best practices for balancing performance improvements with system complexity.

NEW QUESTION # 20
You need to collect and aggregate statistics for the ACCTG service and PAYROLL module, and execute:

Where do you find the output of this command?

• A. By viewing V$SERVICE_STATS
• B. By viewing V$SERV_MOD_ACT_STATS
• C. In the current working directory
• D. In $ORACLE_BASE/diag/rdbms/<db unique name>/<instance name>/trace

Answer: B

Explanation:
When you enable statistics gathering for a specific service and module using DBMS_MONITOR.
SERV_MOD_ACT_STAT_ENABLE, the output is aggregated and can be viewed using the V$SERV_MOD_ACT_STATS dynamic performance view. This view contains the cumulative statistics of database activity broken down by service and module, which is exactly what you collect when executing the provided command.
* B (Incorrect): While many types of trace files are located in the Diagnostic Destination directory (
$ORACLE_BASE/diag), the aggregated statistics for services and modules are not written to trace files but are instead viewable through dynamic performance views.
* C (Incorrect): The V$SERVICE_STATS view provides service-level statistics but does not provide the combined service/module-level breakdown.
* D (Incorrect): The output of the PL/SQL block is not written to a file in the current working directory; it is stored in the data dictionary and accessible via dynamic performance views.
References:
* Oracle Database PL/SQL Packages and Types Reference: DBMS_MONITOR
* Oracle Database Reference: V$SERV_MOD_ACT_STATS

NEW QUESTION # 21
A database instance is suffering poor I/O performance on two frequently accessed large tables.
No Big Table caching occurs in the database.
Examine these parameter settings:

Which are two actions either one of which will allow Big Table caching to occur?

• A. Increasing DB_CACHESIZE to 1 G
• B. Setting PARALLEL_DEGREE_POLICYADAPTIVE
• C. Setting DB_KEEP_CACHE_SIZE to at least 50M
• D. Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 50
• E. Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 25
• F. Setting PARALLEL_DEGREE_POLICYAUTO

Answer: A,E

Explanation:
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

NEW QUESTION # 22
Database performance has degraded recently.
index range scan operations on index ix_sales_time_id are slower due to an increase in buffer gets on sales table blocks.
Examine these attributes displayed by querying DBA_TABLES:

Now, examine these attributes displayed by querying DBA_INDEXES:

Which action will reduce the excessive buffer gets?

• A. Re-create the SALES table sorted in order of index IX_SALES_TIME_ID.
• B. Partition index IX_SALES_TIME_ID using hash partitioning.
• C. Re-create index IX_SALES_TIME_ID using ADVANCED COMPRESSION.
• D. Re-create the SALES table using the columns in IX_SALES_TIME_ID as the hash partitioning key.

Answer: C

Explanation:
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

NEW QUESTION # 23
Which two statements are true about cursor sharing?

• A. Setting optimizer_capture_sql_plan_baselines to TRUE loads all adaptive plans for the same statement into the cursor cache.
• B. Setting Cursor_sharing to FORCE can result in a plan that is suboptimal for the majority of values bound to a bind variable when executing a cursor with one or more bind variables.
• C. Adaptive Cursor Sharing requires histograms on filtered columns, used in equality predicates, to allow different execution plans to be generated for statements whose bound values would normally generate different plans at hard parse time.
• D. Setting cursor_sharing to EXACT prevents Adaptive Cursor Sharing from being used.
• E. Adaptive Cursor Sharing guarantees that a suboptimal plan will never be used on any execution of a SQL statement.

Answer: B,D

Explanation:
A: WhenCursor_sharingis set toFORCE, 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: Settingcursor_sharingtoEXACTensures 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. WithEXACT, there's no cursor sharing for statements with different literals, hence no opportunity for ACS to operate.
References:
* Oracle Database SQL Tuning Guide, 19c
* Oracle Database Reference, 19c

NEW QUESTION # 24
Examine these statements and output:

What parameter change activates the generation and use of SQL Plan Directives7

• A. optimizer_adaptive_statistics = TRUE
• B. optimizer_features_enable=12.2.0.1
• C. optimizer_adaptive_plans=TRUE
• D. optimizer_capture_sql_plan_baselines_TRUE
• E. optimizer_dynamic_sampling=11

Answer: A

Explanation:
The optimizer_adaptive_statistics parameter, when set to TRUE, enables the optimizer to use adaptive statistics, such as SQL Plan Directives, to help improve plans by automatically adjusting them based on the actual execution statistics.
References:
* Oracle Database SQL Tuning Guide, 19c

NEW QUESTION # 25
Examine this command:

What is the maximum number of baselines generated by this command that you can have at any given time?

• A. 0
• B. 1
• C. 2
• D. 3

Answer: D

Explanation:
TheDBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATEprocedure 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. Theparameters of the CREATE_BASELINE_TEMPLATEprocedure 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

NEW QUESTION # 26
Examine this statement and output:

Which three statements are true?

• A. Session 9822 will always stop waiting if the session that owns the TX enqueue issues a COMMIT statement as session 9822 is the first session in the transaction queue.
• B. Session 8779 may be waiting for a user or application response.
• C. Session 9857 is not waiting.
• D. Session 9857 waited 1354 seconds for another process, which was also waiting for a transaction to end.
• E. Session 8779 may be waiting due to a network problem.
• F. Both 9822 and 8779 sessions are waiting for operating system resources.

Answer: A,B,E

Explanation:
For this SQL statement and output, we can analyze theEVENTcolumn to understand the type of wait:
B: The event "SQL*Net message from client" typically indicates that the session is waiting for a response from the client. This can be due to a network issue, user response, or an application processing delay.
E: The event "SQL*Net message from client" also implies that the session is idle waiting for the client (a user or an application) to send a request to the server. This event usually indicates that the session is not actively working but is instead waiting for the next command.
F: The wait event "enq: TX - row lock contention" suggests that session 9822 is waiting for a row-level lock held by another session. If the holding session issues a COMMIT or ROLLBACK, the lock will be released, and session 9822 will stop waiting. Since this session is experiencing row lock contention, it implies it's waiting for a specific transaction to complete.
References:
* Oracle Database Reference, 19c
* Oracle Wait Events Documentation

NEW QUESTION # 27
What is the right time to stop tuning an Oracle database?

• A. When the buffer cache and library cache hit ratio is above 95%
• B. When the allocated budget for performance tuning has been exhausted
• C. When the I/O is less than 10% of the DB time
• D. When all the concurrency waits are eliminated from the Top 10

Answer: B

Explanation:
The right time to stop tuning an Oracle database is often determined by the point of diminishing returns - when the cost of further tuning (in terms of time, resources, or money) exceeds the performance benefits gained.
This is often related to the budget allocated for performance tuning.
* A (Correct):When the allocated budget for performance tuning has been exhausted, it may be time to stop tuning unless the benefits of further tuning justify requesting additional budget.
* B (Incorrect):Eliminating all concurrency waits from the Top 10 is an unrealistic goal since some waits are inevitable and can occur due to application design, which might not be possible to eliminate completely.
* C (Incorrect):The buffer cache and library cache hit ratio being above 95% does not necessarily indicate that the database is fully optimized. Hit ratios are not reliable indicators of database performance and should not be used as sole criteria to end tuning efforts.
* D (Incorrect):Having I/O less than 10% of DB time is not a definitive indicator to stop tuning. It is essential to consider the overall performance goals and whether they have been met rather than focusing solely on I/O metrics.
References:
* Oracle Database Performance Tuning Guide:Introduction to Performance Tuning
* Oracle Database 2 Day + Performance Tuning Guide:Understanding the Tuning Process

NEW QUESTION # 28
Accessing the SALES tables causes excessive db file sequential read wait events.
Examine this AWR except:

Now, examine these attributes displayed by querying dba_tables:

Finally, examine these parameter settings:

Which two must both be used to reduce these excessive waits?

• A. Partition the SALES table.
• B. Compress the SALES table.
• C. Increase PCTFREE for the SALES table.
• D. Re-create the SALES table.
• E. Coalesce all sales table indexes.

Answer: A,B

Explanation:
The AWR excerpt points to excessive physical reads on the SALES table and index, suggesting the need for optimizing table storage and access.
Partitioning the SALES table (A) can reduce 'db file sequential read' waits by breaking down the large SALES table into smaller, more manageable pieces. This can localize the data and reduce the I/O necessary for query operations.
Compressing the SALES table (D) can also help reduce I/O by minimizing the amount of data that needs to be read from disk. This can also improve cache utilization and reduce the 'db file sequential read' waits.
References:
* Oracle Database VLDB and Partitioning Guide, 19c
* Oracle Database Administrator's Guide, 19c
These changes are recommended based on Oracle's best practices for managing large tables and reducing I/O waits, ensuring better performance and efficiency.

NEW QUESTION # 29
Which two options are part of a Soft Parse operation?

• A. SQL Optimization
• B. Semantic Check
• C. Syntax Check
• D. Shared Pool Memory Allocation
• E. SQL Row Source Generation

Answer: B

Explanation:
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

NEW QUESTION # 30
What are the least elevated values of statistics_level and C0NTR0LJ4ANAGEMENT_PACK_ACCESS that allow the usage of Monitoring of Database Operations?

• A. STATISTICS_LEVEL=BASIC and CONTROL_MANAGEMENT_PACK ACCESS=DIAGOSTIC
• B. STATISTICS_LEVEL=TYPICAL and
  CONTROL_MANAGEMENT_PACK_ACCESS-DIAGOSTIC*TUNING
• C. STATISTICS_LEVEL=TYPICAL and CONTROL_MANAGEMENT_PACK_ACCESS=DIAGOSTIC
• D. STATISTICS_LEVEL=ALL and
  CONTROL_MANAGEMENT_PACK_ACCESS=DIAGOSTIC+TUNING

Answer: D

Explanation:
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

NEW QUESTION # 31
Users complain about slowness and session interruptions. Additional checks reveal the following error in the application log:

Which file has additional information about this error?

• A. Session trace file SQL trace file automatically generated by the error
• B. ASH report
• C. SQL trace file automatically generated by the error
• D. Alert log

Answer: D

Explanation:
When an ORA-00060 deadlock error occurs, detailed information about the error and the deadlock graph are dumped into the alert log. This log contains a trace file name that you can use to find additional detailed information about the sessions involved in the deadlock and the SQL statements they were executing.
References:
* Oracle Database Administrator's Guide, 19c
* Oracle Database Error Messages, 19c

NEW QUESTION # 32
Database performance has degraded recently.
index range scan operations on index ix_sales_time_id are slower due to an increase in buffer gets on sales table blocks.
Examine these attributes displayed by querying DBA_TABLES:

Now, examine these attributes displayed by querying DBA_INDEXES:

Which action will reduce the excessive buffer gets?

• A. Re-create the SALES table sorted in order of index IX_SALES_TIME_ID.
• B. Partition index IX_SALES_TIME_ID using hash partitioning.
• C. Re-create index IX_SALES_TIME_ID using ADVANCED COMPRESSION.
• D. Re-create the SALES table using the columns in IX_SALES_TIME_ID as the hash partitioning key.

Answer: C

Explanation:
Given that index range scan operations on IX_SALES_TIME_ID are 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 using ADVANCED COMPRESSION can 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 the SALES table 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 in IX_SALES_TIME_ID as a hash partitioning key for the SALES 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

NEW QUESTION # 33
SGA_TARGET and PGA_AGGREGATE_TARGET are configured to nonzero values.
MEMORY_target is then set to a nonzero value but memory_MAX_TARGET is not set.
Which two statements are true?

• A.
• B.
• C.
• D.
• E.
• F.
• G.

Answer: C,F

Explanation:
When MEMORY_TARGET is set to a nonzero value, Oracle automatically manages the memory allocation between the System Global Area (SGA) and the Program Global Area (PGA). If MEMORY_MAX_TARGET is not explicitly set, Oracle will behave in the following manner:
* MEMORY_MAX_TARGET will default to the value of MEMORY_TARGET, assuming the platform allows for the value of MEMORY_TARGET to be increased dynamically. This means that MEMORY_TARGET represents both the initial allocation and the maximum limit for the dynamically managed memory unless MEMORY_MAX_TARGET is specified differently.
* If MEMORY_TARGET is set to a value that is less than the sum of the current values of SGA_TARGET and PGA_AGGREGATE_TARGET, Oracle will use the higher sum as the default value for MEMORY_MAX_TARGET to ensure that there is adequate memory for both areas. The database instance will not start if MEMORY_TARGET is not sufficient to accommodate the combined SGA and PGA requirements.
References
* Oracle Database Administrator's Guide 19c: Automatic Memory Management
* Oracle Database Performance Tuning Guide 19c: Using Automatic Memory Management

NEW QUESTION # 34
Which two statements are true about session wait information contained in v$session or v$session_wait?

• A. Rows for sessions that are not waiting always contain the total wait time since the session started.
• B. Rows for sessions that are currently waiting have a wait time of 0.
• C. Rows for sessions that are not waiting might contain the actual wait time for the last event for which they waited.
• D. Rows for sessions that are currently waiting have their wait time incremented every microsecond.
• E. Rows for sessions displaying WAITED UNKNOWN TIME in the STATE column indicate that the session is still waiting.

Answer: B,C

Explanation:
In theV$SESSIONview, Oracle provides information about the session waits:
B: When theWAIT_TIMEcolumn has a value of 0, it signifies that the session is currently waiting for a resource. This column represents the duration of the current or last wait.
C: If the session is not actively waiting, theWAIT_TIMEcolumn shows the time the session spent waiting for the last wait event. If theSTATEcolumn is showing "WAITED KNOWN TIME", it means the session is not currently waiting, but it indicates the time for which it had waited.
References:
* Oracle Database Reference, 19c
* Oracle Database Performance Tuning Guide, 19c

NEW QUESTION # 35
You must configure and enable Database Smart Flash Cache for a database.
You configure these flash devices:

Examine these parameter settings:

What must be configured so that the database uses these devices for the Database Smart Flash Cache?

• A. Set DB_FLASH_CACHE_SIZE to 256G and change device /dev/sdk to 128G.
• B. Set DB_FLASH_CACHE_SIZE parameter to 192G.
• C. Disable Automatic Memory Management and set SGA_TARGET to 256G.
• D. Set DB_FLASH_CACHE_SIZE parameter to 128G, 64G.
• E. Set DB_FLASH_CACHE_SIZE to 192G and MEMORY_TARGET to 256G.

Answer: D

Explanation:
To configure and enable Database Smart Flash Cache, you must set the DB_FLASH_CACHE_SIZE parameter to reflect the combined size of the flash devices you intend to use for the cache. In this scenario, two flash devices are configured: /dev/sdj with 128G and /dev/sdk with 64G.
* Determine the combined size of the flash devices intended for the Database Smart Flash Cache. In this case, it's 128G + 64G = 192G.
* However, Oracle documentation suggests setting DB_FLASH_CACHE_SIZE to the exact sizes of the individual devices, separated by a comma when multiple devices are used.
* Modify the parameter in the database initialization file (init.ora or spfile.ora) or using an ALTER SYSTEM command. Here's the command for altering the system setting:
ALTER SYSTEM SET DB_FLASH_CACHE_SIZE='128G,64G' SCOPE=SPFILE;
* Since this is a static parameter, a database restart is required for the changes to take effect.
* Upon database startup, it will allocate the Database Smart Flash Cache using the provided sizes for the specified devices.
It is important to note that MEMORY_TARGET and MEMORY_MAX_TARGET parameters should be configured independently of DB_FLASH_CACHE_SIZE. They control the Oracle memory management for the SGA and PGA, and do not directly correlate with the flash cache configuration.
References
* Oracle Database 19c Documentation on Database Smart Flash Cache
* Oracle Support Articles and Community Discussions on DB_FLASH_CACHE_SIZE Configuration

NEW QUESTION # 36
You need to transport performance data from a Standard Edition to an Enterprise Edition database. What is the recommended method to do this?

• A. Export the data by using the expdp utility and parameter file spuexp.par from the Statspack repository and import it by using impdp into Export the data by using expdp from the Statspack repository and import it by using impdp into the AWR repository.
• B. Export the data by using expdp from Statspack and import it by using $ORACLE_HOME/rdbms/admin
  /awrload into the AWR repository.
• C. Export the data by using the exp utility and parameter file spuexp.par from the Statspack repository and import it by using imp into a dedicated Statspack schema on the destination.
• D. Export the data by using expdp from the ftatspack repository and import it by using impdp into the AWR repository.

Answer: C

Explanation:
To transport performance data from an Oracle Database Standard Edition, which uses Statspack, to an Enterprise Edition database, which uses AWR, you must consider the compatibility of data structures and repository schemas between these tools. The recommended method is:
* D (Correct): Export the data using the exp utility with a parameter file appropriate for Statspack (like spuexp.par) from the Statspack repository and import it into a dedicated Statspack schema on the destination. Since Statspack and AWR use different schemas, it's not recommended to import Statspack data directly into the AWR repository.
The other options are incorrect because:
* A (Incorrect): expdp is not designed to export from Statspack, and awrload is intended for loading from an AWR export file, not a Statspack export.
* B (Incorrect): Although expdp and impdp are used for exporting and importing data, the AWR repository schema is different from the Statspack schema, so importing Statspack data directly into the AWR repository is not recommended.
* C (Incorrect): Using expdp to export from Statspack and then importing directly into the AWR repository is not the correct approach due to the schema differences between Statspack and AWR.
References:
* Oracle Database Performance Tuning Guide: Migrating from Statspack to AWR

NEW QUESTION # 37
Which two statements are true about the use and monitoring of Buffer Cache Hit ratios and their value in tuning Database I/O performance?

• A. The buffer cache advisory view v$db_cache_advice provides advice on cache hit ratios appropriate for the instance workload.
• B. A 60% cache hit ratio can be observed for database instances which have very good I/O performance.
• C. The performance of workloads that primarily generate full table scans and fast full index scans are always affected by the cache hit ratio.
• D. A 99% cache hit ratio can be observed for database instances which have very poor I/O performance.
• E. Both the RECYCLE and KEEP buffer caches should always have a very high cache hit ratio.

Answer: A,D

Explanation:
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

NEW QUESTION # 38
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Oracle 1Z0-084 exam consists of multiple-choice questions that are designed to evaluate the candidate's knowledge and understanding of Oracle Database 19c Performance and Tuning Management. 1Z0-084 exam is conducted online and can be taken from anywhere in the world. 1Z0-084 exam is time-bound, and candidates are required to complete it within the specified time limit.

 

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