Valid 1z1-084 Test Answers & Oracle 1z1-084 Exam PDF
Oracle 1z1-084 Certification Real 2025 Mock Exam
The Oracle 1z1-084 exam measures the candidate's understanding of various topics such as database architecture, memory management, SQL tuning, database performance analysis, and more. It is aimed at professionals who are responsible for managing and maintaining databases, ensuring their optimal performance, and troubleshooting issues that may arise.
NEW QUESTION # 13
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. ASH report
- B. SQL trace file automatically generated by the error
- C. Session trace file SQL trace file automatically generated by the error
- D. Alert log
Answer: D
Explanation:
When an ORA-00060 deadlock error occurs, detailed information about the error and the deadlock graph are dumped into the alert log. This log contains a trace file name that you can use to find additional detailed information about the sessions involved in the deadlock and the SQL statements they were executing.
References:
* Oracle Database Administrator's Guide, 19c
* Oracle Database Error Messages, 19c
NEW QUESTION # 14
Examine this statement and output:
Which three statements are true?
- A. Session 9857 waited 1354 seconds for another process, which was also waiting for a transaction to end.
- B. Session 8779 may be waiting due to a network problem.
- C. Session 9822 will always stop waiting if the session that owns the TX enqueue issues a COMMIT statement as session 9822 is the first session in the transaction queue.
- D. Session 9857 is not waiting.
- E. Both 9822 and 8779 sessions are waiting for operating system resources.
- F. Session 8779 may be waiting for a user or application response.
Answer: B,C,F
Explanation:
For this SQL statement and output, we can analyze theEVENTcolumn to understand the type of wait:
B: The event "SQL*Net message from client" typically indicates that the session is waiting for a response from the client. This can be due to a network issue, user response, or an application processing delay.
E: The event "SQL*Net message from client" also implies that the session is idle waiting for the client (a user or an application) to send a request to the server. This event usually indicates that the session is not actively working but is instead waiting for the next command.
F: The wait event "enq: TX - row lock contention" suggests that session 9822 is waiting for a row-level lock held by another session. If the holding session issues a COMMIT or ROLLBACK, the lock will be released, and session 9822 will stop waiting. Since this session is experiencing row lock contention, it implies it's waiting for a specific transaction to complete.
References:
* Oracle Database Reference, 19c
* Oracle Wait Events Documentation
NEW QUESTION # 15
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 Profiles as well as SQL Plan Baseline are implemented using hints, so they both generate the same plan.
- C. The SQL Plan Baseline must be accepted in order to be used for the execution plan.
- D. The execution plan is the one enforced by the SQL Plan Baseline.
- E. The execution plan is the one enforced by the SQL Profile.
- F. The existence of two concurrent plan stability methods generates a child cursor for every execution.
Answer: C,E
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 # 16
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. Replace the FETCH FIRST clause with ROWNUM to enable the use of an index on SALES.
- C. 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.
- D. Collect a new set of statistics on PRODUCT, CUSTOMERS, and SALES because the current stats are inaccurate.
- E. Enable Adaptive Plans so that Oracle can change the Join method as well as the Join order for this query.
Answer: A
Explanation:
The execution plan shows a full table access for theSALEStable. To reduce the execution time, creating an index onSALES.TIME_IDwould 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 theORDER BYclause, the optimizer can take advantage of the index to efficiently sort and limit the result set to the ten most recent sales.
* B (Incorrect):ReplacingFETCH FIRSTwithROWNUMwould 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 theORDER BYcolumn.
* E (Incorrect):Creating an index onSALES.CUST_IDcould improve join performance but would not address the performance issue caused by the lack of an index on theORDER BYcolumn.
References:
* Oracle Database SQL Tuning Guide:Managing Indexes
* Oracle Database SQL Tuning Guide:Using Indexes and Clusters
NEW QUESTION # 17
Which two Oracle Database features use database services?
- A. Oracle SQL Performance Management
- B. Oracle SQL Tuning Advisor
- C. Oracle Scheduler
- D. Oracle Automatic Reoptimization
- E. Database Resource Manager
Answer: C,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 # 18
Examine these statements and output:
What parameter change activates the generation and use of SQL Plan Directives7
- A. optimizer_dynamic_sampling=11
- B. optimizer_capture_sql_plan_baselines_TRUE
- C. optimizer_features_enable=12.2.0.1
- D. optimizer_adaptive_statistics = TRUE
- E. optimizer_adaptive_plans=TRUE
Answer: D
Explanation:
The optimizer_adaptive_statistics parameter, when set to TRUE, enables the optimizer to use adaptive statistics, such as SQL Plan Directives, to help improve plans by automatically adjusting them based on the actual execution statistics.
References:
* Oracle Database SQL Tuning Guide, 19c
NEW QUESTION # 19
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_PROCESS_MEM_SUMMARY
- B. DBA_HIST_PGASTAT
- C. DBA_HIST_SQLTEXT
- D. DBA_HIST_ACTIVE_SESS_HISTORY
- E. DBA_HIST_SQLSTAT
Answer: A,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 # 20
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. With a target of 800 MB or more, all one-pass execution work areas would be eliminated.
- D. PGAA_AGGREGATE should be set to at least 800 MB.
Answer: C
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 # 21
Which two options are part of a Soft Parse operation?
- A. Syntax Check
- B. SQL Optimization
- C. Shared Pool Memory Allocation
- D. Semantic Check
- E. SQL Row Source Generation
Answer: D
Explanation:
During a soft parse, Oracle checks the shared SQL area to see if an incoming SQL statement matches one already in the shared pool. This operation includes syntax and semantic checks. The syntax check ensures the statement is properly formed, and the semantic check confirms that all the objects referenced in the SQL statement exist and that the user has the necessary privileges to access them.References:
* Oracle Database Concepts, 19c
* Oracle Database SQL Tuning Guide, 19c
NEW QUESTION # 22
Which two statements are true about space usage in temporary tablespaces?
- A. 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.
- B. When a global temporary table instantiation is too large to fit in memory, space is allocated in a temporary tablespace.
- C. Lack of temporary tablespace space for sort operations can be prevented by using temporary tablespace groups.
- D. When a session consumes all temporary tablespace storage, then the session would hang until the temporary space used by that session is cleared.
- E. Temporary tablespaces setting Includes quotas to limit temporary space used by a session for that Temporary tablespace.
Answer: B,C
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 # 23
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. Active Session History report
- B. SQL Tuning Advisor
- C. AWR Compare Periods report
- D. SQL Performance Analyzer
Answer: A
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 # 24
SGA_TARGET and PGA_AGGREGATE_TARGET are configured to nonzero values.
MEMORY_target is then set to a nonzero value but memory_MAX_TARGET is not set.
Which two statements are true?
- A.

- B.

- C.

- D.

- E.

- F.

- G.

Answer: A,B
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 # 25
You must configure and enable Database Smart Flash Cache for a database.
You configure these flash devices:
Examine these parameter settings:
What must be configured so that the database uses these devices for the Database Smart Flash Cache?
- A. Disable Automatic Memory Management and set SGA_TARGET to 256G.
- B. Set DB_FLASH_CACHE_SIZE parameter to 192G.
- C. Set DB_FLASH_CACHE_SIZE to 192G and MEMORY_TARGET to 256G.
- D. Set DB_FLASH_CACHE_SIZE to 256G and change device /dev/sdk to 128G.
- E. Set DB_FLASH_CACHE_SIZE parameter to 128G, 64G.
Answer: E
Explanation:
To configure and enable Database Smart Flash Cache, you must set the DB_FLASH_CACHE_SIZE parameter to reflect the combined size of the flash devices you intend to use for the cache. In this scenario, two flash devices are configured: /dev/sdj with 128G and /dev/sdk with 64G.
* Determine the combined size of the flash devices intended for the Database Smart Flash Cache. In this case, it's 128G + 64G = 192G.
* However, Oracle documentation suggests setting DB_FLASH_CACHE_SIZE to the exact sizes of the individual devices, separated by a comma when multiple devices are used.
* Modify the parameter in the database initialization file (init.ora or spfile.ora) or using an ALTER SYSTEM command. Here's the command for altering the system setting:
ALTER SYSTEM SET DB_FLASH_CACHE_SIZE='128G,64G' SCOPE=SPFILE;
* Since this is a static parameter, a database restart is required for the changes to take effect.
* Upon database startup, it will allocate the Database Smart Flash Cache using the provided sizes for the specified devices.
It is important to note that MEMORY_TARGET and MEMORY_MAX_TARGET parameters should be configured independently of DB_FLASH_CACHE_SIZE. They control the Oracle memory management for the SGA and PGA, and do not directly correlate with the flash cache configuration.
References
* Oracle Database 19c Documentation on Database Smart Flash Cache
* Oracle Support Articles and Community Discussions on DB_FLASH_CACHE_SIZE Configuration
NEW QUESTION # 26
Examine this statement and its corresponding execution plan:
Which phase introduces the CONCATENATION step?
- A. SQL Adaptive Execution
- B. SQL Transformation
- C. SQL Row Source Generation
- D. SQL Semantic Check
- E. SQL Execution
Answer: B
Explanation:
The CONCATENATION step in an execution plan is introduced during the SQL Transformation phase. This phase is part of the optimizer's query transformations which can include various techniques to rewrite the query for more efficient execution. The CONCATENATION operation is used to combine the results of two separate SQL operations, typically when there is an OR condition in the WHERE clause, as seen in the provided query.
References:
* Oracle Database SQL Tuning Guide, 19c
* Oracle Database Concepts, 19c
NEW QUESTION # 27
Which two types of performance problems are reported by ADDM for PDBS?
- A. SGA sizing issues
- B. I/O capacity limits
- C. Excessive checkpoint writes
- D. Top SQL statements
- E. User I/O waits
Answer: B,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 # 28
Which two statements are true about the use and monitoring of Buffer Cache Hit ratios and their value in tuning Database I/O performance?
- A. The buffer cache advisory view v$db_cache_advice provides advice on cache hit ratios appropriate for the instance workload.
- B. Both the RECYCLE and KEEP buffer caches should always have a very high cache hit ratio.
- C. A 60% cache hit ratio can be observed for database instances which have very good I/O performance.
- D. The performance of workloads that primarily generate full table scans and fast full index scans are always affected by the cache hit ratio.
- E. A 99% cache hit ratio can be observed for database instances which have very poor I/O performance.
Answer: A,E
Explanation:
A high buffer cache hit ratio typically indicates that the database is effectively using the buffer cache and does not often need to read data from disk. However, this metric alone is not a reliable indicator of the I/O performance of the database for several reasons:
* Full table scans and fast full index scans (A) can bypass the buffer cache by design if the blocks are not
* deemed reusable shortly, which can impact the cache hit ratio.
* A high cache hit ratio (B) can be misleading if the database performance is poor due to other factors, such as inefficient queries or contention issues.
* The buffer cache advisory (C) is a more valuable tool for understanding the potential impact of different cache sizes on the database's I/O performance. It simulates scenarios with different cache sizes and provides a more targeted recommendation.
* The RECYCLE and KEEP buffer caches (D) are specialized caches designed for certain scenarios.
While high hit ratios can be beneficial, they are not universally required; some workloads might not be significantly impacted by lower hit ratios in these caches.
* A lower cache hit ratio (E) does not necessarily mean poor I/O performance. In some cases, a system with a well-designed storage subsystem and efficient queries might perform well even with a lower cache hit ratio.
References
* Oracle Database 19c Performance Tuning Guide - Buffer Cache Hit Ratio
* Oracle Database 19c Performance Tuning Guide - v$db_cache_advice
NEW QUESTION # 29
You need to collect and aggregate statistics for the ACCTG service and PAYROLL module, and execute:
Where do you find the output of this command?
- A. In $ORACLE_BASE/diag/rdbms/<db unique name>/<instance name>/trace
- B. By viewing V$SERVICE_STATS
- C. In the current working directory
- D. By viewing V$SERV_MOD_ACT_STATS
Answer: D
Explanation:
When you enable statistics gathering for a specific service and module using DBMS_MONITOR.
SERV_MOD_ACT_STAT_ENABLE, the output is aggregated and can be viewed using the V$SERV_MOD_ACT_STATS dynamic performance view. This view contains the cumulative statistics of database activity broken down by service and module, which is exactly what you collect when executing the provided command.
* B (Incorrect): While many types of trace files are located in the Diagnostic Destination directory (
$ORACLE_BASE/diag), the aggregated statistics for services and modules are not written to trace files but are instead viewable through dynamic performance views.
* C (Incorrect): The V$SERVICE_STATS view provides service-level statistics but does not provide the combined service/module-level breakdown.
* D (Incorrect): The output of the PL/SQL block is not written to a file in the current working directory; it is stored in the data dictionary and accessible via dynamic performance views.
References:
* Oracle Database PL/SQL Packages and Types Reference: DBMS_MONITOR
* Oracle Database Reference: V$SERV_MOD_ACT_STATS
NEW QUESTION # 30
Which two actions can cause invalidation or loss of one or more results in the SQL Query Result Cache?
- A. A request was made by the RCBG background process in a physical standby database that is opened read only and whose primary has a result cache.
- B. A request was made by the RCBG background of a non-RAC database.
- C. One or more results were aged out of the result cache.
- D. Decreasing the value set for RESULT_CACHE_REMOTE_EXPIRATION.
- E. result_cache_max_size is set dynamically to 0.
Answer: C,E
Explanation:
The SQL Query Result Cache stores the results of queries and PL/SQL function calls for reuse. However, entries in the result cache can be invalidated or lost under certain conditions:
A: Results can be aged out of the cache when the cache becomes full and new results need to be stored. This process ensures that the cache does not exceed its allocated memory and that it contains the most recently used entries.
B: Setting theRESULT_CACHE_MAX_SIZEparameter to 0 will effectively disable the result cache and all cached results will be lost, as Oracle will no longer allocate any memory to the result cache.
References:
* Oracle Database Performance Tuning Guide, 19c
NEW QUESTION # 31
You want to reduce the amount of db file scattered read that is generated in the database. You execute the SQL Tuning Advisor against the relevant workload. Which two can be part of the expected result?
- A. recommendations regarding partitioning the tables
- B. recommendations regarding the creation of additional indexes
- C. recommendations regarding rewriting the SQL statements
- D. recommendations regarding the creation of materialized views
- E. recommendations regarding the creation of SQL Patches
Answer: B,C
Explanation:
https://docs.oracle.com/en/database/oracle/oracle-database/21/tgsql/sql-tuning-advisor.html#GUID-
8E1A39CB-A491-4254-8B31-9B1DF7B52AA1
The goal is to reduce the db file scattered read waits, which are associated with full table scans. These are I
/O operations where Oracle retrieves data blocks scattered across the disk, typically when large amounts of data are read inefficiently. Running the SQL Tuning Advisor analyzes the workload and provides tuning recommendations. Let's evaluate the options.
Why A. Recommendations regarding the creation of additional indexes is correct:
* Full table scans (which cause db file scattered read) often occur because suitable indexes are missing.
* The SQL Tuning Advisor can identify queries that would benefit from indexes and recommend creating them. Indexes allow the database to access data more efficiently using row lookups, reducing the need for full table scans.
Why B. Recommendations regarding rewriting the SQL statements is correct:
* Sometimes, poorly written SQL statements cause inefficient execution plans that lead to db file scattered read.
* SQL Tuning Advisor can recommend SQL rewrites to make better use of indexes, avoid full table scans, or optimize joins. For example:
* Rewriting predicates to use indexed columns.
* Using hints to guide the optimizer.
Why Other Options Are Incorrect:
* C. Recommendations regarding the creation of materialized views:
* Materialized views are typically recommended to optimize complex queries involving aggregations or joins, not to address db file scattered read directly. They are less relevant for solving I/O issues caused by full table scans in this context.
* D. Recommendations regarding the creation of SQL Patches:
* SQL Patches are used to influence the execution plan for specific SQL statements. While SQL Patches can potentially fix performance issues, the SQL Tuning Advisor focuses on improving SQL and database design rather than patching queries.
* E. Recommendations regarding partitioning the tables:
* Partitioning tables can improve query performance, especially for very large datasets. However, this is a database design-level recommendation and is not typically provided by SQL Tuning Advisor. Partitioning would not directly target db file scattered read.
How SQL Tuning Advisor Helps:
The SQL Tuning Advisor provides actionable recommendations, such as:
* Creating indexes to reduce full table scans.
* Rewriting SQL to optimize the execution plan.
* Improving statistics to help the optimizer make better decisions.
References to Oracle Documentation:
* Oracle Database 19c Performance Tuning Guide:
* Section: Using SQL Tuning Advisor to Optimize Workloads.
* Explains recommendations for indexes and SQL rewrites to reduce I/O.
* Understanding Wait Events:
* Details about db file scattered read and how to address it.
NEW QUESTION # 32
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 are notifications from the Oracle Database Server of an existing or impending problem.
- D. They are logged in the alert log.
- E. They may contain suggestions for correcting the identified problems.
- 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 # 33
Which three types of statistics are captured by statspack with snap level 6?
- A. Plan usage data
- B. Parent and child latches
- C. Enqueue statistics
- D. Optimizer execution plans
- E. Parent and child latches
- F. Segment-level statistics
Answer: C,E,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 # 34
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To achieve the Oracle 1Z0-084 certification, candidates must pass a 120-minute exam consisting of 80 multiple-choice questions. 1z1-084 exam covers topics such as performance tuning fundamentals, SQL tuning, memory management, and database resource management. Candidates must have a deep understanding of Oracle Database 19c architecture, configuration, and management to pass the exam.
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