1z1-084 Dumps PDF - 1z1-084 Real Exam Questions Answers [Q20-Q41]

1z1-084 Dumps PDF - 1z1-084 Real Exam Questions Answers

Get Started: 1z1-084 Exam [2025] Dumps Oracle PDF Questions

NEW QUESTION # 20
Examine this AWRreport excerpt:

You must reduce the impact of database I/O, without increasing buffer cache size and without modifying the SQL statements.
Which compression option satisfies this requirement?

• A. STORE COMPRESS
• B. COLUMN STORE COMPRESS FOR QUERY HIGH
• C. MN STORE COMPRESS FOR QUERY LOW
• D. ROW STORE COMPRESS ADVANCED

Answer: D

Explanation:
To reduce the impact of database I/O without increasing the size of the buffer cache and without modifying SQL statements, you can use table compression. Among the given options,ROW STORE COMPRESS ADVANCEDis the most suitable form of table compression to satisfy this requirement.
Advanced row compression (ROW STORE COMPRESS ADVANCED) is designed to work well with all supported types of data, whether it's OLTP or data warehouse environments. It offers a higher level of compression than basic table compression (ROW STORE COMPRESS BASIC)without significant overhead during DML operations. This feature can help reduce the amount of I/O required to retrieve data by storing it more efficiently on disk.
* A, B, D:WhileCOLUMN STORE COMPRESS FOR QUERY HIGHandROW STORE
COMPRESSare both valid compression types,COLUMN STORE COMPRESS FOR QUERY
* HIGHapplies to the In-Memory column store and is not available in all versions and editions, andROW STORE COMPRESSis less advanced thanROW STORE COMPRESS ADVANCED.
References:
* Oracle Database Concepts Guide:Table Compression
* Oracle Database Performance Tuning Guide:Row Compression

NEW QUESTION # 21
Which two types of performance problems are reported by ADDM for PDBS?

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

Answer: C,D

Explanation:
ADDM (Automatic Database Diagnostic Monitor) is a key Oracle diagnostic tool that analyzes performance data captured by AWR (Automatic Workload Repository) and provides insights into performance issues. In a PDB (Pluggable Database), ADDM can provide recommendations for various types of performance issues.
Why A. I/O capacity limits is correct:
* ADDM evaluates the performance of a database and identifies I/O bottlenecks that could be impacting query performance.
* I/O capacity limits occur when the database cannot handle the I/O workload effectively, which could be due to disk contention, inadequate I/O throughput, or hardware limitations.
* ADDM reports such issues and suggests remedies like tuning SQL queries, redistributing I/O workloads, or upgrading storage systems.
Why D. Top SQL statements is correct:
* One of the critical capabilities of ADDM is identifying high-resource-consuming SQL statements (Top SQL) that are impacting database performance.
* For PDBs, ADDM provides specific recommendations to optimize these SQL statements, such as improving execution plans, adding indexes, or rewriting queries.
Why Other Options Are Incorrect:
* B. Excessive checkpoint writes:
* While excessive checkpoint writes can occur, ADDM typically focuses on higher-level performance problems like I/O issues or top SQL rather than specific low-level operational events like checkpointing. Excessive checkpoint writes are not commonly reported directly for PDBs by ADDM.
* C. SGA sizing issues:
* ADDM does not directly analyze or provide recommendations for SGA (System Global Area) sizing issues at the PDB level because SGA is managed at the CDB (Container Database) level.
PDBs share the SGA of the CDB.
* E. User I/O waits:
* While user I/O waits are captured in performance metrics, ADDM typically groups them under broader issues like I/O capacity limits. It does not specifically report on "user I/O waits" as a standalone problem.
Key Features of ADDM for PDBs:
* Identifying Top SQL Statements impacting performance.
* Reporting I/O issues, including capacity limits and contention.
* Highlighting inter-PDB resource contention within the same CDB.
References to Oracle Documentation:
* Oracle Database 19c Performance Tuning Guide:
* Section: Using ADDM for Pluggable Databases.
* Details the types of performance issues ADDM reports for PDBs.
* Automatic Database Diagnostic Monitor (ADDM) Concepts:
* Highlights ADDM's ability to analyze I/O, SQL performance, and resource utilization.

NEW QUESTION # 22
This error occurred more than four hours ago in the database:
ORA-04036 PGA memory used by theinstance exceedsPGA_AGGREGATE_LIMIT
You want to know which process and query were at fault.
Which two views should you use for this purpose?

• A. DBA_HIST_PGASTAT
• B. DBA_HIST_SQLTEXT
• C. DBA_HIST_ACTIVE_SESS_HISTORY
• D. DBA_HIST_PROCESS_MEM_SUMMARY
• E. DBA_HIST_SQLSTAT

Answer: C,D

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

NEW QUESTION # 23
Which two statements are true about disabling Automatic Shared Memory Management (ASMM)?

• A. It requires a database instance restart to take effect.
• B. The SGA size remains unaffected after disabling ASMM.
• C. All SGA components retain their current sizes at the time of disabling.
• D. Both SGA_TARGET and SGA_MAX_SIZE must be set to zero.
• E. All auto-tuned SGA components are reset to their original user-defined values.
• F. All SGA components excluding fixed SGA and other internal allocations are readjusted immediately after disabling ASMM.

Answer: B,C

Explanation:
When ASMM is disabled, the sizes of the automatically managed SGA components remain at their current values. ASMM is controlled by the SGA_TARGET parameter. If SGA_TARGET is 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 setting SGA_TARGET to 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 # 24
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. AWR Compare Periods report
• B. SQL Tuning Advisor
• C. SQL Performance Analyzer
• D. Active Session History report

Answer: D

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 # 25
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. Alert log
• C. ASH report
• D. SQL trace file automatically generated by the error

Answer: B

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 # 26
For which two actions can SQL Performance Analyzer be used to assess the impact of changes to SQL performance?

• A. changes to database initialization parameters
• B. operating system upgrades
• C. database consolidation for pluggable databases (PDBs)
• D. operating system and hardware migrations
• E. storage, network, and interconnect changes

Answer: A,C

Explanation:
SQL Performance Analyzer (SPA) can be used to assess the impact of different types of changes on SQL performance. These changes can include database initialization parameters, which can significantly affect how SQL statements are executed and therefore their performance. SPA allows you to capture a workload before and after the change and compare the performance of each SQL statement.
Database consolidation, including moving to pluggable databases (PDBs), can also affect SQL performance.
SPA can analyze the SQL workload to see how consolidation impacts performance, by comparing metrics such as elapsed time and CPU time before and after the consolidation.
References:
* Oracle Database SQL Tuning Guide, 19c
* Oracle Database Performance Tuning Guide, 19c

NEW QUESTION # 27
Which statement is true about DB time in V$$YS_TIME_MODEL?

• A. DB time includes the time spent executing the RMAN backup and restore command.
• B. DB time is organized as a simple list of statistics and any time period is attributable to only one statistic.
• C. DB time can be many times greater than the elapsed time since the database instance started.
• D. DB tine excludes the time spent waiting for a CPU in the operating system run queue.

Answer: C

Explanation:
DB time includes the time spent on user and background processes. It can be greater than the elapsed time because it accumulates the active time of all the processes. For example, if two sessions are each active for 2 seconds at the same time, DB time would accumulate 4 seconds, while the elapsed time would be only 2 seconds.References:
* Oracle Database Performance Tuning Guide, 19c
* Oracle Database Reference, 19c

NEW QUESTION # 28
Which two statements are true about cursor sharing?

• A. 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.
• 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 guarantees that a suboptimal plan will never be used on any execution of a SQL statement.
• D. Setting cursor_sharing to EXACT prevents Adaptive Cursor Sharing from being used.
• E. Setting optimizer_capture_sql_plan_baselines to TRUE loads all adaptive plans for the same statement into the cursor cache.

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 # 29
Which three statements are true about tuning dimensions and details of v$sys_time_model and DB time?

• A. Parse Time Elapsed accounts for successful soft and hard parse operations only.
• B. When WAIT TIME is high, instance tuning may improve performance.
• C. Statspack cannot account for high CPU time when CPU TIME is a Top 10 event in DB time. When CPU time is high, SQL tuning may improve performance.
• D. Systems in which CPU time is dominant need more tuning that those in which WAIT TIME is dominant.
• E. DB Time accounts for all time used by background processes and user sessions.
• F. The proportion of WAIT TIME to CPU TIME always increases with increased system load.

Answer: B,C,E

Explanation:
A: Statspack is a performance diagnostic tool that can help identify high CPU usage issues. High CPU time may indicate that SQL statements need to be tuned for better performance.
D: High wait times can often be reduced by instance tuning, such as adjusting database parameters or improving I/O performance.
F: DB Time is a cumulative time metric that includes the time spent by both user sessions and background processes executing database calls.References:
* Oracle Database Performance Tuning Guide, 19c
* Oracle Database Concepts, 19c

NEW QUESTION # 30
Examine this statement and output:

Which three statements are true?

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

Answer: C,D,E

Explanation:
For this SQL statement and output, we can analyze the EVENT column 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 # 31
Which three types of statistics are captured by statspack with snap level 6?

• A. Segment-level statistics
• B. Parent and child latches
• C. Enqueue statistics
• D. Optimizer execution plans
• E. Plan usage data
• F. Parent and child latches

Answer: A,B,C

Explanation:
Statspack is a performance diagnostic tool provided by Oracle prior to the introduction of the Automatic Workload Repository (AWR). At snap level 6, Statspack captures the following types of statistics:
* A (Correct):Parent and child latches are captured. Latch statistics provide information about contention for latches, which are low-level serialization mechanisms used by Oracle.
* E (Correct):Enqueue statistics, which provide information on the waits for locks that manage the concurrency between users.
* F (Correct):Segment-level statistics, which provide detailed information on database segments such as tables, indexes, etc., to identify I/O and contention issues.
* C (Incorrect):While optimizer execution plans are an essential aspect of performance tuning, detailed execution plan capture is not part of the Statspack report at level 6.
* D (Incorrect):Plan usage data refers to how frequently a plan is being used, which is more associated with AWR and not typically captured in Statspack reports.
References:
* Oracle Database Performance Tuning Guide:Using Statspack

NEW QUESTION # 32
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 SESSION CACHED CURSORS = 500;
• B. ALTER SYSTEM SET CURSOR_SHARING = FORCE;
• C. ALTER SYSTEM SET CURSOR_INVALIDATION = DEFERRED;
• D. ALTER SYSTEM SET CURSOR_SPACE_FOR_TIME - TRUE;

Answer: C

Explanation:
The cursor: pin S wait on X wait 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 the cursor: pin S wait on X wait events.
The other options are incorrect in addressing this issue:
* A (Incorrect): Setting CURSOR_SHARING to FORCE makes the optimizer replace literal values with bind variables. It doesn't address the contention for cursor pins directly.
* B (Incorrect): CURSOR_SPACE_FOR_TIME=TRUE aims 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 X waits.
* D (Incorrect): Increasing SESSION_CACHED_CURSORS caches more session cursors but doesn't necessarily prevent the contention indicated by the cursor: pin S wait on X wait events.
References:
* Oracle Database Reference: CURSOR_INVALIDATION
* Oracle Database Performance Tuning Guide: Reducing Cursor Invalidation

NEW QUESTION # 33
Which two types of performance problems are reported by ADDM for PDBS?

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

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

Answer: C,E

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
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: B

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

NEW QUESTION # 36
What is the right time to stop tuning an Oracle database?

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

Answer: B

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 # 37
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 INMEM0RY_CLAUSE of the Data Pump Export allows modifications to IM column store clause of a table with existing INMEMORY setting.
• B. It must always transports existing INMEMORY attributes.
• C. It ignores the IM column store clause of the exporting objects.
• D. Its TRANSFORM clause can be used to add the INMEMORV clause to exported tables that lack them.
• E. It can generates the INMEMORY clause that matches the table settings at export time.
• F. It always gives preference to the IM column store clause defined at the tablespace level over table-level definitions.

Answer: D,E

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 # 38
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 full scan
• B. db file scattered read
• C. db file sequential read
• D. index range scan

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 # 39
Which two statements are true about disabling Automatic Shared Memory Management (ASMM)?

• A. It requires a database instance restart to take effect.
• B. The SGA size remains unaffected after disabling ASMM.
• C. All SGA components retain their current sizes at the time of disabling.
• D. Both SGA_TARGET and SGA_MAX_SIZE must be set to zero.
• E. All auto-tuned SGA components are reset to their original user-defined values.
• F. All SGA components excluding fixed SGA and other internal allocations are readjusted immediately after disabling ASMM.

Answer: B,C

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 # 40
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. setting dbwr_io_slaves to 64
• C. increasing the value of DB_FILE_MULTIBLOCK_READ_COUNT to 128
• D. increasing the value of DBWRITERPROCESSES to 64,
• E. Increasing the size of MEMORYTARGET

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 the DBWR_IO_SLAVES parameter 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 of DBWRITERPROCESSES enables 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 # 41
......

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