[Apr-2025] 1Z0-084 Dumps Full Questions - Oracle Database 19c Exam Study Guide [Q27-Q52]

[Apr-2025] 1Z0-084 Dumps Full Questions - Oracle Database 19c Exam Study Guide

Exam Questions and Answers for 1Z0-084 Study Guide

Achieving the Oracle 1Z0-084 certification can enhance the professional credibility of database administrators, system administrators, and developers. It validates their knowledge and skills in managing database performance and tuning, which can lead to better job opportunities and higher salaries. Moreover, the certification demonstrates a commitment to continuous learning and professional development in the field of database management.

To prepare for the Oracle 1Z0-084 exam, candidates should have a solid understanding of the Oracle Database architecture and its components. They should also be familiar with the SQL language and have experience in using performance tuning tools such as SQL Tuning Advisor, Automatic Workload Repository (AWR), and Automatic Database Diagnostic Monitor (ADDM). Additionally, candidates should have practical experience in diagnosing and resolving common performance issues.

NEW QUESTION # 27
Which two statements are true about space usage in temporary tablespaces?

A. Temporary tablespaces setting Includes quotas to limit temporary space used by a session for that Temporary tablespace.
B. When a global temporary table instantiation is too large to fit in memory, space is allocated in a temporary tablespace.
C. When a session consumes all temporary tablespace storage, then the session would hang until the temporary space used by that session is cleared.
D. Lack of temporary tablespace space for sort operations can be prevented by using temporary tablespace groups.
E. A sort will fail if a sort to disk requires more disk space and no additional extent can be found/allocated in/for the sort segment.

Answer: B,D

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

NEW QUESTION # 28
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 warning alert will be issued when CPU time exceeds 1 minute for each user call.
B. A critical alert will be issued when CPU time exceeds 2 minutes 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 10000 microseconds for each user call.

Answer: D

Explanation:
In the provided code block, the DBMS_SERVER_ALERT.SET_THRESHOLD procedure 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 the SET_THRESHOLD procedure are as follows:
* The first parameter DBMS_SERVER_ALERT.CPU_TIME_PER_CALL specifies the metric for which the threshold is being set, in this case, the CPU time consumed per database call.
* The second and third parameters DBMS_SERVER_ALERT.OPERATOR_GE and '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 parameters DBMS_SERVER_ALERT.OPERATOR_GE and '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 the DBMS_SERVER_ALERT.SET_THRESHOLD procedure, 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 # 29
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 optimizer_capture_sql_plan_baselines to TRUE loads all adaptive plans for the same statement into the cursor cache.
E. 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.

Answer: A,E

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 # 30
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?

Answer: B,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 # 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. SQL trace file automatically generated by the error
B. Session trace file SQL trace file automatically generated by the error
C. Alert log
D. ASH report

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

Answer: B

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

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

Answer: B,E

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
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?

Answer: A,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 # 35
Which three statements are true about using the in Memory (IM) column store?

A. It does not require all database data to fit in memory to improve query performance.
B. It does not improve performance for queries using cached results of function evaluations on columns from the same table.
C. It does not improve performance for queries using user-defined virtual column results.
D. It does not improve performance for queries that use join groups on columns from different tables.
E. It can improve OLTP workload performance by avoiding the use of indexes.
F. It improves performance for queries joining several tables using bloom filter joins.

Answer: A,E,F

Explanation:
The Oracle In-Memory (IM) column store feature enhances the performance of databases by providing a fast columnar storage format for analytical workloads while also potentially benefiting OLTP workloads.
* C (True):It can improve OLTP workload performance by providing a faster access path for full table scans and reducing the need for indexes in certain scenarios, as the In-Memory store allows for efficient in-memory scans.
* E (True):The In-Memory column store does not require all database data to fit in memory. It can be used selectively for performance-critical tables or partitions, and Oracle Database will manage the population and eviction of data as needed.
* F (True):In-Memory column store can significantly improve performance for queries joining several tables, especially when bloom filters are used, as they are highly efficient with the columnar format for large scans and join processing.
The other options provided are not correct in the context of the In-Memory column store:
* A (False):While In-Memory column store is designed for analytical queries rather than caching results of function evaluations, it does not specifically avoid improving performance for queries using cached results of function evaluations.
* B (False):In-Memory column store can improve the performance of queries that use join groups, which can be used to optimize joins on columns from different tables.
* D (False):In-Memory column store can improve the performance of queries using expressions, including user-defined virtual columns, because it supports expression statistics which help in
* optimizing such queries.
References:
* Oracle Database In-Memory Guide:In-Memory Column Store in Oracle Database
* Oracle Database In-Memory Guide:In-Memory Joins
* Oracle Database In-Memory Guide:In-Memory Aggregation

NEW QUESTION # 36
Examine these commands, which execute successfully:

Which statement is true?

A. ADDM, AWR, and ASH reports can be purged automatically.
B. AD DM is enabled for all pluggable databases.
C. AWR- snapshots in all pluggable databases will be purgedautomatically after every 60 mins.
D. AWR snapshots can be purged manually in pluggable databases.

Answer: D

Explanation:
TheDBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGSprocedure allows setting attributes related to AWR snapshots. While the interval setting controls the frequency of snapshot generation, purging them is a separate process that can be managed either automatically (with retention settings) or manually.References:
* Oracle Database PL/SQL Packages and Types Reference, 19c
* Oracle Multitenant Administrator's Guide, 19c

NEW QUESTION # 37
Which two types of performance problems are reported by ADDM for PDBS?

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

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 # 38
Which two statements are true about space usage in temporary tablespaces?

A. Temporary tablespaces setting Includes quotas to limit temporary space used by a session for that Temporary tablespace.
B. When a global temporary table instantiation is too large to fit in memory, space is allocated in a temporary tablespace.
C. When a session consumes all temporary tablespace storage, then the session would hang until the temporary space used by that session is cleared.
D. Lack of temporary tablespace space for sort operations can be prevented by using temporary tablespace groups.
E. A sort will fail if a sort to disk requires more disk space and no additional extent can be found/allocated in/for the sort segment.

Answer: B,D

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

NEW QUESTION # 39
You must write a statement that returns the ten most recent sales. Examine this statement:

Users complain that the query executes too slowly. Examine the statement's current execution plan:

What must you do to reduce the execution time and why?

A. Create an index on SALES.TIME_ID to force the return of rows in the order specified by the ORDER BY clause.
B. Create an index on SALES.CUST_ID to force an INDEX RANGE SCAN on this index followed by a NESTED LOOP join between CUSTOMERS and SALES.
C. Replace the FETCH FIRST clause with ROWNUM to enable the use of an index on SALES.
D. Enable Adaptive Plans so that Oracle can change the Join method as well as the Join order for this query.
E. Collect a new set of statistics on PRODUCT, CUSTOMERS, and SALES because the current stats are inaccurate.

Answer: A

Explanation:
The execution plan shows a full table access for the SALES table. To reduce the execution time, creating an index on SALES.TIME_ID would be beneficial as it would allow the database to quickly sort and retrieve the most recent sales without the need to perform a full table scan, which is I/O intensive and slower. By indexing TIME_ID, which is used in the ORDER BY clause, the optimizer can take advantage of the index to efficiently sort and limit the result set to the ten most recent sales.
* B (Incorrect): Replacing FETCH FIRST with ROWNUM would not necessarily improve the performance unless there is an appropriate index that the optimizer can use to avoid sorting the entire result set.
* C (Incorrect): There is no indication that the current statistics are inaccurate; hence, collecting new statistics may not lead to performance improvement.
* D (Incorrect): While adaptive plans can provide performance benefits by allowing the optimizer to adapt the execution strategy, the main issue here is the lack of an index on the ORDER BY column.
* E (Incorrect): Creating an index on SALES.CUST_ID could improve join performance but would not address the performance issue caused by the lack of an index on the ORDER BY column.
References:
* Oracle Database SQL Tuning Guide: Managing Indexes
* Oracle Database SQL Tuning Guide: Using Indexes and Clusters

NEW QUESTION # 40
Which Optimizer component helps decide whether to use a nested loop join or a hash join in an adaptive execution plan?

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

Answer: B

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 # 41
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. MN STORE COMPRESS FOR QUERY LOW
C. COLUMN STORE COMPRESS FOR QUERY HIGH
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 # 42
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 conflict between the two plan stability methods results in an error.
B. The SQL Plan Baseline must be accepted in order to be used for the execution plan.
C. The execution plan is the one enforced by the SQL Profile.
D. The SQL Profiles as well as SQL Plan Baseline are implemented using hints, so they both generate the same plan.
E. The existence of two concurrent plan stability methods generates a child cursor for every execution.
F. The execution plan is the one enforced by the SQL Plan Baseline.

Answer: B,C

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 # 43
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 SQL Patches
B. recommendations regarding rewriting the SQL statements
C. recommendations regarding partitioning the tables
D. recommendations regarding the creation of additional indexes
E. recommendations regarding the creation of materialized views

Answer: D,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 # 44
Examine this statement and output:

Which three statements are true?

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

Answer: B,D,F

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 # 45
Which three types of statistics are captured by statspack with snap level 6?

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

Answer: C,D,F

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 # 46
Examine this output of a query of VSPGA_TAPGET_ADVICE:

Which statements is true'

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

Answer: D

Explanation:
The query output from V$PGA_TARGET_ADVICE provides tuning information for the PGA (Program Global Area). Let's break it down step by step:
Key Columns in the Output:
* TARGET_MB:
* Represents the hypothetical PGA_AGGREGATE_TARGET values (in megabytes) evaluated by Oracle.
* CACHE_HIT_PERC:
* The percentage of work areas that could execute in-memory (optimal execution) without requiring temporary disk writes.
* Higher percentages indicate fewer work areas requiring disk I/O.
* ESTD_OVERALLOC_COUNT:
* The estimated number of work areas that need to go to disk (multipass operations or overallocations).
Observations from the Data:
* At TARGET_MB = 700 MB:
* The CACHE_HIT_PERC is 68%.
* The ESTD_OVERALLOC_COUNT is 30. This indicates that some multipass work areas still exist.
* At TARGET_MB = 800 MB:
* The CACHE_HIT_PERC rises to 74%.
* The ESTD_OVERALLOC_COUNT drops to 0. This indicates that no work areas require multipass execution.
* At TARGET_MB = 900 MB and above:
* The CACHE_HIT_PERC increases slightly to 82%-84%.
* The ESTD_OVERALLOC_COUNT remains 0, meaning that all work areas are now either optimal or one-pass.
Why D is Correct:
* At 800 MB or more, the ESTD_OVERALLOC_COUNT is 0, indicating that all one-pass execution work areas are eliminated.
* A one-pass execution requires temporary disk I/O for intermediate results, but with sufficient PGA, these are no longer necessary.
Why Other Options Are Incorrect:
* Option A:
* It mentions all multipass executions work areas would be eliminated at 700 MB. This is incorrect because, at 700 MB, the ESTD_OVERALLOC_COUNT is still 30, indicating some multipass work areas still exist.
* Option B:
* Suggests setting the PGA_AGGREGATE_TARGET to at least 800 MB, which is partially correct but does not address the elimination of one-pass execution.
* Option C:
* Suggests setting the PGA_AGGREGATE_TARGET to at least 700 MB, which is not sufficient to eliminate all one-pass executions, as shown by the ESTD_OVERALLOC_COUNT of 30.

NEW QUESTION # 47
Examine this statement and output:

Which two situations can trigger this error?

A. There is a file in the capture directory.
B. The user lacks the required privileges to execute the DBMS WORKLOAD CAPTURE package or the directory.
C. The instance is unable to access the capture directory.
D. The syntax is incomplete.
E. The capture directory is part of the root file system.

Answer: B,C

Explanation:
The ORA-15505 error indicates that the instance encountered errors while trying to access the specified directory. This could be due to:
A: Insufficient privileges: The user attempting to start the workload capture might not have the required permissions to execute the DBMS_WORKLOAD_CAPTURE package or to read/write to the directory specified.
E: Accessibility: The database instance may not be able to access the directory due to issues such as incorrect directory path, directory does not exist, permission issues at the OS level, or the directory being on a file system that's not accessible to the database instance.
References:
* Oracle Database Error Messages, 19c
* Oracle Database Administrator's Guide, 19c

NEW QUESTION # 48
Which two Oracle Database features use database services?

A. Oracle SQL Performance Management
B. Database Resource Manager
C. Oracle Automatic Reoptimization
D. Oracle SQL Tuning Advisor
E. Oracle Scheduler

Answer: B,E

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 # 49
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. Partition index IX_SALES_TIME_ID using hash partitioning.
B. Re-create index IX_SALES_TIME_ID using ADVANCED COMPRESSION.
C. Re-create the SALES table using the columns in IX_SALES_TIME_ID as the hash partitioning key.
D. Re-create the SALES table sorted in order of index IX_SALES_TIME_ID.

Answer: B

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 # 50
Examine these commands, which execute successfully:

Which statement is true?

A. ADDM, AWR, and ASH reports can be purged automatically.
B. AWR- snapshots in all pluggable databases will be purged automatically after every 60 mins.
C. AD DM is enabled for all pluggable databases.
D. AWR snapshots can be purged manually in pluggable databases.

Answer: D

Explanation:
The DBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGS procedure allows
setting attributes related to AWR snapshots. While the interval setting controls the frequency of snapshot generation, purging them is a separate process that can be managed either automatically (with retention settings) or manually.References:
* Oracle Database PL/SQL Packages and Types Reference, 19c
* Oracle Multitenant Administrator's Guide, 19c

NEW QUESTION # 51
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 DB_KEEP_CACHE_SIZE to at least 50M
C. Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 50
D. Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 25
E. Setting PARALLEL_DEGREE_POLICYAUTO
F. Setting PARALLEL_DEGREE_POLICYADAPTIVE

Answer: A,D

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 # 52
......

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