[Aug 20, 2024] Latest Questions 1z1-084 Guide to Prepare Free Practice Tests [Q12-Q35]

[Aug 20, 2024] Latest Questions 1z1-084 Guide to Prepare Free Practice Tests

Reliable 1z1-084 Dumps Questions Available as Web-Based Practice Test Engine

Oracle 1Z0-084 certification exam is intended for IT professionals who work with Oracle databases on a regular basis. This includes database administrators, performance analysts, and other IT professionals who are responsible for ensuring the optimal performance of Oracle databases. By earning this certification, these professionals can demonstrate to their employers and clients that they have the knowledge and skills required to manage and optimize Oracle databases.

 

NEW QUESTION # 12
Which two statements are true about session wait information contained in v$session or v$session_wait?

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

Answer: C,E

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 # 13
During which application lifecycle phase do you take baselines?

• A. Deployment
• B. Migration or upgrade
• C. Production
• D. Testing
• E. Design and development

Answer: C

Explanation:
Baselines are typically taken during the production phase of the application lifecycle. They provide a snapshot of performance metrics under normal operating conditions which can be used for comparison against future performance. Baselines are essential for understanding how the system performs under its typical workload and for detecting deviations from this expected performance over time, especially after changes like migrations, upgrades, or significant changes in user activity.
References
* Oracle Database 19c Performance Tuning Guide - Managing Performance Through Baselines

NEW QUESTION # 14
An Oracle 19c database uses default values for all optimizer initialization parameters.
After a table undergoes partition maintenance, a large number of wait events occur for:
cursor: pin S wait on X
Which command reduces the number of these wait events?

• A. ALTER SYSTEM SET CURSOR_SPACE_FOR_TIME - TRUE;
• B. ALTER SYSTEM SET SESSION CACHED CURSORS = 500;
• C. ALTER SYSTEM SET CURSOR_INVALIDATION = DEFERRED;
• D. ALTER SYSTEM SET CURSOR_SHARING = FORCE;

Answer: C

Explanation:
Thecursor: pin S wait on Xwait event suggests contention for a cursor pin, which is associated with mutexes (a type of locking mechanism) that protect the library cache to prevent concurrent modifications. This issue can often be alleviated by deferring the invalidation of cursors until the end of the call to reduce contention.
The correct command to use would be:
* C (Correct):ALTER SYSTEM SET CURSOR_INVALIDATION=DEFERRED;This setting defers the invalidation of dependent cursors until the end of the PL/SQL call, which can reduce thecursor: pin S wait on Xwait events.
The other options are incorrect in addressing this issue:
* A (Incorrect):SettingCURSOR_SHARINGtoFORCEmakes the optimizer replace literal values with bind variables. It doesn't address the contention for cursor pins directly.
* B (Incorrect):CURSOR_SPACE_FOR_TIME=TRUEaims to reduce the parsing effort by keeping cursors for prepared statements open. It may increase memory usage but does not directly resolve cursor: pin S wait on Xwaits.
* D (Incorrect):IncreasingSESSION_CACHED_CURSORScaches more session cursors but doesn't necessarily prevent the contention indicated by thecursor: pin S wait on Xwait events.
References:
* Oracle Database Reference:CURSOR_INVALIDATION
* Oracle Database Performance Tuning Guide:Reducing Cursor Invalidation

NEW QUESTION # 15
Buffer cache access is too frequent when querying the SALES table. Examine this command which executes successfully:
ALTER TABLE SALES SHRINK SPACE;
For which access method does query performance on sales improve?

• A. index range scan
• B. index full scan
• C. db file sequential read
• D. db file scattered read

Answer: C

Explanation:
The SHRINK SPACE operation compacts the table, which can reduce fragmentation and thus improve performance for sequential reads of the table. This operation could improve full table scans, which are typically associated with db file sequential read wait events.
References:
* Oracle Database Administrator's Guide, 19c

NEW QUESTION # 16
Examine this code block, which executes successfully:
DBMS_SERVER_ALERT. SET_THRESHOLD (
DBMS_SERVER_ALERT.CPU_TIME_PER_CALL, DBMS_SERVER_ALERT. OPERATOR_GE, '8000', DBMS_SERVER_ALERT.OPERATOR_GE, '10000', 1, 2, 'inst1', DBMS_SERVER_ALERT.OBJECT_TYPE_SERVICE, 'main.regress.rdbms.dev.us.example.com') ;

What will happen?

• A. A critical alert will be issued when CPU time exceeds 10000 microseconds for each user call.
• B. A warning alert will be issued when CPU time exceeds 1 minute for each user call.
• C. A warning alert will be issued only when CPU time exceeds 10000 microseconds for each user call.
• D. A critical alert will be issued when CPU time exceeds 2 minutes for each user call.

Answer: A

Explanation:
In the provided code block, theDBMS_SERVER_ALERT.SET_THRESHOLDprocedure is used to set alert thresholds for the CPU time per call in Oracle Database. This procedure is a part of Oracle's Database Server Alert system, which monitors various metrics and generates alerts when certain thresholds are exceeded.
The parameters passed to theSET_THRESHOLDprocedure are as follows:
* The first parameterDBMS_SERVER_ALERT.CPU_TIME_PER_CALLspecifies the metric for which the threshold is being set, in this case, the CPU time consumed per database call.
* The second and third parametersDBMS_SERVER_ALERT.OPERATOR_GEand'8000'specify the warning threshold level and its value, respectively. However, these are not relevant to the answer as they are overridden by the critical threshold settings.
* The fourth and fifth parametersDBMS_SERVER_ALERT.OPERATOR_GEand'10000'set the critical threshold level and its value. This means that a critical alert will be generated when the CPU time per call exceeds 10000 microseconds.
* The remaining parameters specify the warning and critical alert intervals, the instance name, the object type, and the service name. These are not directly relevant to the behavior described in the options.
Thus, the correct answer is B, as the critical threshold for CPU time per call is set to 10000 microseconds, and the system is configured to issue a critical alert when this threshold is exceeded.
References:
* Oracle Database 19c documentation on theDBMS_SERVER_ALERT.SET_THRESHOLDprocedure, which details the parameters and usage of this procedure for setting alert thresholds within Oracle Database monitoring system.
* Oracle Database Performance Tuning Guide, which provides best practices and methodologies for monitoring and tuning Oracle Database performance, including the use of server alerts and thresholds.

NEW QUESTION # 17
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,G

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 # 18
You execute the following:
EXECUTE DBMS_AuTO_TASK_ADMIN.DISABLE;
Which advisor remains enabled?

• A. SQL Plan Management Evolve Advisor
• B. Automatic Optimizer Statistics Collection
• C. Automatic SQL Tuning
• D. Optimizer Statistics Advisor
• E. Automatic Segment Advisor

Answer: B

Explanation:
When you executeDBMS_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.
References
* Oracle Database 19c PL/SQL Packages and Types Reference - DBMS_AUTO_TASK_ADMIN
* Oracle Database 19c Database Administrator's Guide - Managing Optimizer Statistics

NEW QUESTION # 19
Examine this statement and output:

Which three statements are true?

• A. Session 9857 is not waiting.
• B. Both 9822 and 8779 sessions are waiting for operating system resources.
• C. 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.
• D. Session 8779 may be waiting for a user or application response.
• E. Session 9857 waited 1354 seconds for another process, which was also waiting for a transaction to end.
• F. Session 8779 may be waiting due to a network problem.

Answer: C,D,F

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 # 20
You manage a 19c database with default optimizer settings.
This statement is used extensively as subquery in the application queries:
SELECT city_id FROM sh2.sales WHERE city_id=:Bl
You notice the performance of these queries is often poor and, therefore, execute:
SELECT city_id,COUNT(*) FROM sh2.sales GROUP BY city_id;
Examine the results:

There is no index on the CITY_ID column.
Which two options improve the performance?

• A. Create an index on the CITY IP column.
• B. Activate the adaptive plans.
• C. Use a SQL Profile to enforce the appropriate plan.
• D. Generate frequency histograms on the CITY__ID column.
• E. Force the subquery to use dynamic sampling.

Answer: A,D

Explanation:
In this scenario, creating an index and generating frequency histograms are two methods that can potentially improve performance:
* A (Correct):Generating frequency histograms on theCITY_IDcolumn can help the optimizer make better decisions regarding the execution plan, especially if the data distribution is skewed. Histograms provide the optimizer with more detailed information about the data distribution in a column, which is particularly useful for columns with non-uniform distributions.
* B (Correct):Creating an index on theCITY_IDcolumn would speed up queries that filter on this column, especially if it's used frequently in the WHERE clause as a filter. An index would allow for an index range scan instead of a full table scan, reducing the I/O and time needed to execute such queries.
* C (Incorrect):While SQL profiles can be used to improve the performance of specific SQL statements, they are usually not the first choice for such a problem, and creating a profile does not replace the need for proper indexing or statistics.
* D (Incorrect):Forcing the subquery to use dynamic sampling might not provide a consistent performance benefit, especially if the table statistics are not representative or are outdated. However, dynamic sampling is not as effective as having accurate statistics and a well-chosen index.
* E (Incorrect):Adaptive plans can adjust the execution strategy based on the conditions at runtime.
While they can be useful in certain scenarios, in this case, creating an index and ensuring accurate statistics would likely provide a more significant performance improvement.
References:
* Oracle Database SQL Tuning Guide:Managing Optimizer Statistics
* Oracle Database SQL Tuning Guide:Using Indexes and Clusters

NEW QUESTION # 21
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 192G and MEMORY_TARGET to 256G.
• B. Disable Automatic Memory Management and set SGA_TARGET to 256G.
• C. Set DB_FLASH_CACHE_SIZE parameter to 128G, 64G.
• D. Set DB_FLASH_CACHE_SIZE parameter to 192G.
• E. Set DB_FLASH_CACHE_SIZE to 256G and change device /dev/sdk to 128G.

Answer: C

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 youintend 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 # 22
A database supporting a mixed workload is hosted on a server with 64 CPUs.
A large number of free buffer waits and buffer busy waits occur affecting performance.
The buffer cache size was then increased but after a few hours, the same wait events occur more often than before the change.
Examine these parameter settings:

Which two actions can help reduce the number of these waits7

• A. increasing the value of DB_FILE_MULTIBLOCK_READ_COUNT to 128
• B. setting dbwr_io_slaves to 64
• C. Increasing the size of MEMORYTARGET
• D. increasing the value of DBWRITERPROCESSES to 64,
• E. reducing the values of DB_FILE_MULTILOCK_READ_COUNT to 64

Answer: B,D

Explanation:
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

NEW QUESTION # 23
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. Re-create the SALES table.
• B. Increase PCTFREE for the SALES table.
• C. Partition the SALES table.
• D. Compress the SALES table.
• E. Coalesce all sales table indexes.

Answer: C,D

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 # 24
Examine this output of a query of VSPGA_TAPGET_ADVICE:

Which statements is true'

• A. PGAA_AGGREGATE should be set to at least 800 MB.
• B. With a target of 800 MB or more, all one-pass execution work areas would be eliminated.
• C. With a target of 700 MB or more, all multipass executions work areas would be eliminated.
• D. GGREGATE_TARGET should be set to at least 700 MB.

Answer: C

Explanation:
The V$PGA_TARGET_ADVICE view provides advice on potential performance improvements by adjusting the PGA_AGGREGATE_TARGET parameter. The column ESTD_OVERALLOC_COUNT indicates the estimated number of work areas that would perform multiple passes if the PGA_AGGREGATE_TARGET were set to the size in the TARGET_MB column.
A: According to the output, at the target of 700 MB, the ESTD_OVERALLOC_COUNT is 30. This suggests that if PGA_AGGREGATE_TARGET is set to 700 MB, 30 multipass execution work areas would be required. If we look further down, at the target of 800 MB, the ESTD_OVERALLOC_COUNT is 0, indicating that increasing PGA_AGGREGATE_TARGET to 800 MB or more would eliminate the need for multipass executions, not at 700 MB as initially suggested by the option. Hence, the verified answer derived from the data is slightly nuanced; it should be 800 MB to eliminate all multipass executions.
References:
* Oracle Database Performance Tuning Guide, 19c
* Oracle Database Reference, 19c

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

Answer: C,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_TARGETis 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):IncreasingDB_BIG_TABLE_CACHE_PERCENT_TARGETto 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):IncreasingDB_CACHE_SIZEto 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:IncreasingDB_BIG_TABLE_CACHE_PERCENT_TARGETto 50 without adjusting the overall size of the cache might still not be sufficient if theDB_CACHE_SIZEis not large enough to hold the big tables.
* B:SettingDB_KEEP_CACHE_SIZEto at least 50M only specifies a separate buffer pool for objects with the KEEP cache attribute and does not affect Big Table caching.
* E:andF:Changing thePARALLEL_DEGREE_POLICYtoADAPTIVEorAUTOinfluences 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 # 26
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 the creation of additional indexes
• B. recommendations regarding rewriting the SQL statements
• C. recommendations regarding the creation of SQL Patches
• D. recommendations regarding the creation of materialized views
• E. recommendations regarding partitioning the tables

Answer: A,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 # 27
Which application lifecycle phase could be managed reactively?

• A. Deployment
• B. Upgrade or migration
• C. Production
• D. Testing
• E. Design and development

Answer: C

Explanation:
The production phase of the application lifecycle is often managed reactively. While proactive measures and performance tuning are essential, unforeseen issues can arise in production that require immediate attention and resolution. Reactive management involves monitoring performance and responding to issues as they occur, ensuring the application maintains acceptable performance levels for end-users.
References
* Oracle Database 19c Performance Tuning Guide - Reactive Tuning

NEW QUESTION # 28
Which three statements are true about server-generated alerts?

• A. They are logged in the alert log.
• B. They provide notifications but never any suggestions for correcting the identified problems.
• C. They can be viewed only from the Cloud Control Database home page.
• D. Their threshold settings can be modified by using DBMS_SERVER_ALERT.
• E. They are notifications from the Oracle Database Server of an existing or impending problem.
• F. They may contain suggestions for correcting the identified problems.

Answer: A,E,F

Explanation:
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, usingDBMS_SERVER_ALERT, is not correct. Threshold settings are typically adjusted through Enterprise Manager or by modifying specific initialization parameters directly.
References:
* 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

NEW QUESTION # 29
Which two types of performance problems are reported by ADDM for PDBS?

• A. User I/O waits
• B. SGA sizing issues
• C. I/O capacity limits
• D. Excessive checkpoint writes
• E. Top SQL statements

Answer: A,C

Explanation:
The Automatic Database Diagnostic Monitor (ADDM) analyzes and reports on various types of performance problems. For Pluggable Databases (PDBs), it can identify issues such as I/O capacity limits which may hinder the overall performance by causing bottlenecks. Additionally, ADDM can report on user I/O waits, which can indicate performance issues related to the time it takes for user queries to read data from the disk.
References:
* Oracle Multitenant Administrator's Guide, 19c
* Oracle Database Performance Tuning Guide, 19c

NEW QUESTION # 30
Which Optimizer component helps decide whether to use a nested loop join or a hash join in an adaptive execution plan?

• A. Automatic Reoptimization
• B. SQL Plan Directives
• C. Statistics Feedback
• D. Dynamic Statistics
• E. Statistics Collector

Answer: E

Explanation:
In an adaptive execution plan, the Optimizer makes runtime decisions between nested loop and hash joins using a statistics collector. The collector is a row source that collects statistics about the rows it processes and can adapt the plan based on the number of rows processed.
References:
* Oracle Database SQL Tuning Guide, 19c

NEW QUESTION # 31
Database performance degraded between 23:15 and 23:30 for the last three nights. The awr snapshot interval is one hour. The AODM report contains nothing about this performance problem.
With which tool can you further analyze this problem?

• A. SQL Tuning Advisor
• B. Active Session History report
• C. AWR Compare Periods report
• D. SQL Performance Analyzer

Answer: B

Explanation:
The Active Session History (ASH) report is a tool that provides detailed information about active sessions for the time period specified. Since the AWR snapshot interval is one hour and does not capture the granularity needed for this issue, ASH reports aremore suitable as they contain more granular data for sessions that were active during the period of interest.
References:
* Oracle Database Performance Tuning Guide, 19c

NEW QUESTION # 32
Multiple sessions are inserting data concurrently into a table that has an LOB column.
At some point in time, one of the sessions cannot find available space in the LOB segment and needs to allocate a new extent.
Which wait event will be raised in the other sessions that need space in the LOB column?

• A. enq: TX - allocate ITL entry
• B. enq: HW - contention
• C. enq: SQ - contention
• D. enq: TM - contention

Answer: B

Explanation:
When sessions concurrently insert data into a table with an LOB column and one session needs to allocate a new extent because it cannot find available space, the wait event associated with this contention is "enq: HW - contention". The HW stands for High Water Mark which is related to space allocation in the database segment.
When asession needs to allocate a new extent, it may raise this wait event in other sessions that are also attempting to allocate space in the same LOB segment.
References
* Oracle Database 19c Reference Guide - enq: HW - contention

NEW QUESTION # 33
Examine these statements and output:

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

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

Answer: E

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 # 34
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. SQL trace file automatically generated by the error
• B. ASH report
• C. Alert log
• D. Session trace file SQL trace file automatically generated by the error

Answer: C

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 # 35
......

Oracle 1Z0-084 exam is an essential certification for IT professionals who specialize in database performance and tuning management. Oracle Database 19c Performance and Tuning Management certification validates the candidates' expertise in designing, implementing, and managing Oracle Database 19c performance and tuning solutions. 1z1-084 exam covers a wide range of topics related to performance tuning, including database architecture, memory management, SQL tuning, database monitoring, and optimization techniques.

 

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