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NEW QUESTION # 22
Which application lifecycle phase could be managed reactively?
- A. Deployment
- B. Upgrade or migration
- C. Production
- D. Design and development
- E. Testing
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 # 23
Which Optimizer component helps decide whether to use a nested loop join or a hash join in an adaptive execution plan?
- A. Statistics Collector
- B. Automatic Reoptimization
- C. SQL Plan Directives
- D. Statistics Feedback
- E. Dynamic Statistics
Answer: A
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 # 24
Which three statements are true about server-generated alerts?
- A. Their threshold settings can be modified by using DBMS_SERVER_ALERT.
- B. They provide notifications but never any suggestions for correcting the identified problems.
- C. They may contain suggestions for correcting the identified problems.
- D. They are logged in the alert log.
- E. They are notifications from the Oracle Database Server of an existing or impending problem.
- F. They can be viewed only from the Cloud Control Database home page.
Answer: C,D,E
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 # 25
Examine this statement and output:
Which three statements are true?
- A. Session 8779 may be waiting for a user or application response.
- B. 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.
- C. Session 8779 may be waiting due to a network problem.
- D. Session 9857 is not waiting.
- E. Both 9822 and 8779 sessions are waiting for operating system resources.
- F. Session 9857 waited 1354 seconds for another process, which was also waiting for a transaction to end.
Answer: A,B,C
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 # 26
You are informed that the RMAN session that is performing the database duplication is much slower than usual. You want to know the approximate time when the rman operation will be completed.
Which view has this information?
- A. V$SESSION
- B. V$RMAN_BACKUP_JOB_DETAILS
- C. V$SESSTAT
- D. V$SESSION_LONGOPS
Answer: D
Explanation:
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
NEW QUESTION # 27
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 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.
- B. Export the data by using expdp from the ftatspack repository and import it by using impdp into the AWR repository.
- C. Export the data by using expdp from Statspack and import it by using
$ORACLE_HOME/rdbms/admin/awrload into the AWRrepository. - D. 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.
Answer: A
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 theexputility 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):expdpis not designed to export from Statspack, andawrloadis intended for loading from an AWR export file, not a Statspack export.
* B (Incorrect):Althoughexpdpandimpdpare 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):Usingexpdpto 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 # 28
Which two statements are true about cursor sharing?
- A. Setting cursor_sharing to EXACT prevents Adaptive Cursor Sharing from being used.
- B. 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.
- C. Adaptive Cursor Sharing guarantees that a suboptimal plan will never be used on any execution of a SQL statement.
- D. 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.
- E. Setting optimizer_capture_sql_plan_baselines to TRUE loads all adaptive plans for the same statement into the cursor cache.
Answer: A,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 # 29
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 index IX_SALES_TIME_ID using ADVANCED COMPRESSION.
- B. Re-create the SALES table using the columns in IX_SALES_TIME_ID as the hash partitioning key.
- C. Partition index IX_SALES_TIME_ID using hash partitioning.
- D. Re-create the SALES table sorted in order of index IX_SALES_TIME_ID.
Answer: A
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 # 30
Which two statements are true about session wait information contained in v$session or v$session_wait?
- A. Rows for sessions that are not waiting always contain the total wait time since the session started.
- B. Rows for sessions that are not waiting might contain the actual wait time for the last event for which they waited.
- C. Rows for sessions that are currently waiting have their wait time incremented every microsecond.
- D. Rows for sessions that are currently waiting have a wait time of 0.
- E. Rows for sessions displaying WAITED UNKNOWN TIME in the STATE column indicate that the session is still waiting.
Answer: B,D
Explanation:
In theV$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 # 31
Which two Oracle Database features use database services?
- A. Oracle Scheduler
- B. Database Resource Manager
- C. Oracle SQL Performance Management
- D. Oracle SQL Tuning Advisor
- E. Oracle Automatic Reoptimization
Answer: A,B
Explanation:
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
NEW QUESTION # 32
You use SQL Tuning Advisor to tune a given SQL statement.
The analysis eventually results in the implementation of a SQL Profile.
You then generate the new SQL Profile plan and enforce it using a SQL PlanBaselinebut forget to disable the SQLProfile and a few days later you find out that the SQL Profile is generating a new execution plan.
Which two statements are true?
- A. The execution plan is the one enforced by the SQL Profile.
- B. The SQL Plan Baseline must be accepted in order to be used for the execution plan.
- C. The SQL Profiles as well as SQL Plan Baseline are implemented using hints, so they both generate the same plan.
- D. The execution plan is the one enforced by the SQL Plan Baseline.
- E. The existence of two concurrent plan stability methods generates a child cursor for every execution.
- F. The conflict between the two plan stability methods results in an error.
Answer: A,B
Explanation:
When both a SQL Profile and a SQL Plan Baseline are in place, the SQL Profile has a stronger preference and the optimizer is more likely to choose the execution plan from the SQL Profile.
C: A SQL Profile is generally more influential than a SQL Plan Baseline because it contains additional statistics and directives that help the optimizer to generate a more efficient execution plan. If both exist, the optimizer will use the profile's plan unless the baseline's plan is proven to be better through the SQL performance monitoring process.
E: SQL Plan Baselines must be accepted before they can be used by the optimizer. If a SQL Plan Baseline is not accepted, it will not be considered for generating the execution plan. Therefore, the presence of an unaccepted SQL Plan Baseline will not automatically force the optimizer to use its plan.
References:
* Oracle Database SQL Tuning Guide, 19c
* Oracle Database Administrator's Guide, 19c
NEW QUESTION # 33
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. reducing the values of DB_FILE_MULTILOCK_READ_COUNT to 64
- B. Increasing the size of MEMORYTARGET
- C. increasing the value of DBWRITERPROCESSES to 64,
- D. increasing the value of DB_FILE_MULTIBLOCK_READ_COUNT to 128
- E. setting dbwr_io_slaves to 64
Answer: C,E
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 # 34
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 partitioning the tables
- C. recommendations regarding rewriting the SQL statements
- D. recommendations regarding the creation of materialized views
- E. recommendations regarding the creation of SQL Patches
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 # 35
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 # 36
Which two statements are true about Data Pump import for objects that used the in Memory (IM) column store in their source database?
- A. Its TRANSFORM clause can be used to add the INMEMORV clause to exported tables that lack them.
- B. It ignores the IM column store clause of the exporting objects.
- C. It can generates the INMEMORY clause that matches the table settings at export time.
- D. It must always transports existing INMEMORY attributes.
- E. Its INMEM0RY_CLAUSE of the Data Pump Export allows modifications to IM column store clause of a table with existing INMEMORY setting.
- F. It always gives preference to the IM column store clause defined at the tablespace level over table-level definitions.
Answer: A,C
Explanation:
When importing objects that used the In-Memory (IM) column store in their source database using Oracle Data Pump, the following statements are true:
* D (Correct):TheTRANSFORMclause can be used to alter object creation DDL during import operations. This can include adding theINMEMORYclause to tables that were not originally using the IM column store.
* F (Correct):The import operation can preserve theINMEMORYattributes of tables as they were at the time of export, effectively replicating the IM column store settings from the source database.
The other statements are not accurate in the context of Data Pump import:
* A (Incorrect):Data Pump does not give preference to the IM column store clauses at the tablespace level over table-level definitions unless explicitly specified by theTRANSFORMclause.
* B (Incorrect):While Data Pump can transport existingINMEMORYattributes, it is not mandatory. It is controlled by theINCLUDEorEXCLUDEData Pump parameters or theTRANSFORMclause.
* C (Incorrect):TheINMEMORY_CLAUSEparameter is not part of the Data Pump Export utility. To modify the IM column store clauses, you would use theTRANSFORMparameter during import, not export.
* E (Incorrect):Data Pump does not ignore the IM column store clause unless specifically instructed to do so via theEXCLUDEparameter.
References:
* Oracle Database Utilities:Data Pump Export
* Oracle Database Utilities:Data Pump Import
NEW QUESTION # 37
The CURS0R_SHARING and OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES parameters are set to default. The top five wait events in an awr report are due to a large number of hard parses because of several almost identical SQL statements.
Which two actions could reduce the number of hard parses?
- A. Set OPTIMIZER_CAPTURE_SQL_PLAN_BASELINESto TRUE.
- B. Create the RECYCLE cache and cache tables accessed by the SQL statements.
- C. Create the KEEP cache and cache tables accessed by the SQL statements.
- D. Increase the size of the library cache.
- E. Set the CURSOR_SHARING parameter to FORCE.
Answer: D,E
Explanation:
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
NEW QUESTION # 38
Which two statements are true about disabling Automatic Shared Memory Management (ASMM)?
- A. Both SGA_TARGET and SGA_MAX_SIZE must be set to zero.
- B. It requires a database instance restart to take effect.
- C. All SGA components excluding fixed SGA and other internal allocations are readjusted immediately after disabling ASMM.
- D. All SGA components retain their current sizes at the time of disabling.
- E. The SGA size remains unaffected after disabling ASMM.
- F. All auto-tuned SGA components are reset to their original user-defined values.
Answer: D,E
Explanation:
When ASMM is disabled, the sizes of the automatically managed SGA components remain at their current values. ASMM is controlled by theSGA_TARGETparameter. IfSGA_TARGETis set to a non-zero value, ASMM is enabled and Oracle will automatically manage the sizes of the various SGA components. When ASMM is disabled, by settingSGA_TARGETto zero, the SGA components that were automatically sized will retain their current sizes rather than being reset to their original user-defined values. The overall size of the SGA remains the same unless manually changed by modifying individual component sizes or SGA_MAX_SIZE.
References:
* Oracle Database Administration Guide, 19c
* Oracle Database Performance Tuning Guide, 19c
NEW QUESTION # 39
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