[2025年05月29日] 最速合格には素晴らしい1z1-084無料テストPDF本日更新です
無料でゲット！最新の2025年最新の有効な練習Oracle Database 19c 1z1-084問題と解答でテストエンジン
Oracle 1Z0-084試験は、Oracle Database 19cの経験があり、データベース管理の基本的な概念に精通している個人を対象としています。候補者は、SQL、データベースアーキテクチャ、パフォーマンスチューニング技術に強い理解を持っている必要があります。試験を受ける前に、候補者は少なくとも2年間Oracle Database 19cでの作業経験を持っていることが推奨されます。
質問 # 30
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. Systems in which CPU time is dominant need more tuning that those in which WAIT TIME is dominant.
- 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. DB Time accounts for all time used by background processes and user sessions.
- E. The proportion of WAIT TIME to CPU TIME always increases with increased system load.
- F. When WAIT TIME is high, instance tuning may improve performance.
正解：C、D、F
解説：
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
質問 # 31
Which three statements are true about using the in Memory (IM) column store?
- A. It does not improve performance for queries using cached results of function evaluations on columns from the same table.
- B. It does not improve performance for queries that use join groups on columns from different tables.
- C. It does not improve performance for queries using user-defined virtual column results.
- D. It can improve OLTP workload performance by avoiding the use of indexes.
- E. It does not require all database data to fit in memory to improve query performance.
- F. It improves performance for queries joining several tables using bloom filter joins.
正解：D、E、F
解説：
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
質問 # 32
Examine these statements and output:
What parameter change activates the generation and use of SQL Plan Directives7
- A. optimizer_dynamic_sampling=11
- B. optimizer_features_enable=12.2.0.1
- C. optimizer_adaptive_statistics = TRUE
- D. optimizer_adaptive_plans=TRUE
- E. optimizer_capture_sql_plan_baselines_TRUE
正解：C
解説：
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
質問 # 33
Examine this statement and output:
Which three statements are true?
- A. Both 9822 and 8779 sessions are waiting for operating system resources.
- B. Session 9822 will always stop waiting if the session that owns the TX enqueue issues a COMMIT statement as session 9822 is the first session in the transaction queue.
- C. Session 8779 may be waiting for a user or application response.
- D. Session 9857 waited 1354 seconds for another process, which was also waiting for a transaction to end.
- E. Session 9857 is not waiting.
- F. Session 8779 may be waiting due to a network problem.
正解：B、C、F
解説：
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
質問 # 34
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 always gives preference to the IM column store clause defined at the tablespace level over table-level definitions.
- C. It can generates the INMEMORY clause that matches the table settings at export time.
- D. Its TRANSFORM clause can be used to add the INMEMORV clause to exported tables that lack them.
- E. It must always transports existing INMEMORY attributes.
- F. It ignores the IM column store clause of the exporting objects.
正解：C、D
解説：
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
質問 # 35
Which two types of performance problems are reported by ADDM for PDBS?
- A. Top SQL statements
- B. SGA sizing issues
- C. Excessive checkpoint writes
- D. I/O capacity limits
- E. User I/O waits
正解：A、D
解説：
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.
質問 # 36
Which two options are part of a Soft Parse operation?
- A. Semantic Check
- B. SQL Optimization
- C. Syntax Check
- D. Shared Pool Memory Allocation
- E. SQL Row Source Generation
正解：A
解説：
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
質問 # 37
You must configure and enable Database Smart Flash Cache for a database.
You configure these flash devices:
Examine these parameter settings:
What must be configured so that the database uses these devices for the Database Smart Flash Cache?
- A. Set DB_FLASH_CACHE_SIZE parameter to 192G.
- B. Disable Automatic Memory Management and set SGA_TARGET to 256G.
- C. Set DB_FLASH_CACHE_SIZE to 192G and MEMORY_TARGET to 256G.
- D. Set DB_FLASH_CACHE_SIZE parameter to 128G, 64G.
- E. Set DB_FLASH_CACHE_SIZE to 256G and change device /dev/sdk to 128G.
正解：D
解説：
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
質問 # 38
What are the least elevated values of statistics_level and C0NTR0LJ4ANAGEMENT_PACK_ACCESS that allow the usage of Monitoring of Database Operations?
- A. STATISTICS_LEVEL=BASIC and CONTROL_MANAGEMENT_PACK ACCESS=DIAGOSTIC
- B. STATISTICS_LEVEL=TYPICAL and CONTROL_MANAGEMENT_PACK_ACCESS=DIAGOSTIC
- C. STATISTICS_LEVEL=TYPICAL and CONTROL_MANAGEMENT_PACK_ACCESS-
DIAGOSTIC*TUNING - D. STATISTICS_LEVEL=ALL and
CONTROL_MANAGEMENT_PACK_ACCESS=DIAGOSTIC+TUNING
正解：D
解説：
Monitoring of Database Operations requires that the STATISTICS_LEVEL parameter be set to ALL and CONTROL_MANAGEMENT_PACK_ACCESS be set to DIAGNOSTIC+TUNING. These settings enable all the advisory features and automatic tuning features within the Oracle Database, including the Automatic Workload Repository (AWR), Automatic Database Diagnostic Monitor (ADDM), and the full functionality of the SQL Tuning Advisor and SQL Access Advisor, which are components of the Diagnostic and Tuning packs.
* STATISTICS_LEVEL=ALL: This setting enables the collection of all system statistics for problem detection and self-tuning purposes.
* CONTROL_MANAGEMENT_PACK_ACCESS=DIAGNOSTIC+TUNING: This grants access to both the Diagnostic Pack and the Tuning Pack, which are essential for detailed performance monitoring and tuning capabilities.
References:
* Oracle Database Reference: STATISTICS_LEVEL
* Oracle Database Licensing Information User Manual: Oracle Database Management Packs
質問 # 39
Examine this statement and output:
Which two situations can trigger this error?
- A. The capture directory is part of the root file system.
- B. The user lacks the required privileges to execute the DBMS WORKLOAD CAPTURE package or the directory.
- C. There is a file in the capture directory.
- D. The instance is unable to access the capture directory.
- E. The syntax is incomplete.
正解：B、D
解説：
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
質問 # 40
The CURS0R_SHARING and OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES parameters are set to default. The top five wait events in an awr report are due to a large number of hard parses because of several almost identical SQL statements.
Which two actions could reduce the number of hard parses?
- A. Create the RECYCLE cache and cache tables accessed by the SQL statements.
- B. Increase the size of the library cache.
- C. Create the KEEP cache and cache tables accessed by the SQL statements.
- D. Set OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES to TRUE.
- E. Set the CURSOR_SHARING parameter to FORCE.
正解：B、E
解説：
To reduce the number of hard parses due to several almost identical SQL statements, you can take the following actions:
* C (Correct): Increasing the size of the library cache can help reduce hard parses by providing more memory to store more execution plans. This allows SQL statements to be shared more effectively.
* E (Correct): Setting the CURSOR_SHARING parameter to FORCE will cause Oracle to replace literals in SQL statements with bind variables, which can significantly reduce the number of hard parses by making it more likely that similar SQL statements will share the same execution plan.
The other options do not directly impact the number of hard parses:
* A (Incorrect): Creating the KEEP cache and caching tables accessed by the SQL statements can improve performance for those tables, but it does not directly reduce the number of hard parses.
* B (Incorrect): Creating the RECYCLE cache and caching tables accessed by the SQL statements can make it more likely that objects will be removed from the cache quickly, which does not help with hard parse issues.
* D (Incorrect): Setting OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES to TRUE can help stabilize SQL execution plans but will not reduce the number of hard parses. This parameter is used to automatically capture SQL plan baselines for repeatable SQL statements, which can prevent performance regressions due to plan changes.
References:
* Oracle Database Performance Tuning Guide: Minimizing Hard Parses
* Oracle Database SQL Tuning Guide: CURSOR_SHARING
質問 # 41
Examine this code block, which executes successfully:
DBMS_SERVER_ALERT. SET_THRESHOLD (
DBMS_SERVER_ALERT.CPU_TIME_PER_CALL, DBMS_SERVER_ALERT. OPERATOR_GE, '8000', DBMS_SERVER_ALERT.OPERATOR_GE, '10000', 1, 2, 'inst1', DBMS_SERVER_ALERT.OBJECT_TYPE_SERVICE, 'main.regress.rdbms.dev.us.example.com') ;
What will happen?
- A. A critical alert will be issued when CPU time exceeds 10000 microseconds for each user call.
- B. A warning alert will be issued when CPU time exceeds 1 minute for each user call.
- C. A critical alert will be issued when CPU time exceeds 2 minutes for each user call.
- D. A warning alert will be issued only when CPU time exceeds 10000 microseconds for each user call.
正解：A
解説：
In the provided code block, theDBMS_SERVER_ALERT.SET_THRESHOLDprocedure is used to set alert thresholds for the CPU time per call in Oracle Database. This procedure is a part of Oracle's Database Server Alert system, which monitors various metrics and generates alerts when certain thresholds are exceeded.
The parameters passed to theSET_THRESHOLDprocedure are as follows:
* The first parameterDBMS_SERVER_ALERT.CPU_TIME_PER_CALLspecifies the metric for which the threshold is being set, in this case, the CPU time consumed per database call.
* The second and third parametersDBMS_SERVER_ALERT.OPERATOR_GEand'8000'specify the warning threshold level and its value, respectively. However, these are not relevant to the answer as they are overridden by the critical threshold settings.
* The fourth and fifth parametersDBMS_SERVER_ALERT.OPERATOR_GEand'10000'set the critical threshold level and its value. This means that a critical alert will be generated when the CPU time per call exceeds 10000 microseconds.
* The remaining parameters specify the warning and critical alert intervals, the instance name, the object type, and the service name. These are not directly relevant to the behavior described in the options.
Thus, the correct answer is B, as the critical threshold for CPU time per call is set to 10000 microseconds, and the system is configured to issue a critical alert when this threshold is exceeded.
References:
* Oracle Database 19c documentation on theDBMS_SERVER_ALERT.SET_THRESHOLDprocedure, which details the parameters and usage of this procedure for setting alert thresholds within Oracle Database monitoring system.
* Oracle Database Performance Tuning Guide, which provides best practices and methodologies for monitoring and tuning Oracle Database performance, including the use of server alerts and thresholds.
質問 # 42
What is the right time to stop tuning an Oracle database?
- A. When all the concurrency waits are eliminated from the Top 10
- B. When the buffer cache and library cache hit ratio is above 95%
- C. When the allocated budget for performance tuning has been exhausted
- D. When the I/O is less than 10% of the DB time
正解：C
解説：
The right time to stop tuning an Oracle database is often determined by the point of diminishing returns - when the cost of further tuning (in terms of time, resources, or money) exceeds the performance benefits gained.
This is often related to the budget allocated for performance tuning.
* A (Correct):When the allocated budget for performance tuning has been exhausted, it may be time to stop tuning unless the benefits of further tuning justify requesting additional budget.
* B (Incorrect):Eliminating all concurrency waits from the Top 10 is an unrealistic goal since some waits are inevitable and can occur due to application design, which might not be possible to eliminate completely.
* C (Incorrect):The buffer cache and library cache hit ratio being above 95% does not necessarily indicate that the database is fully optimized. Hit ratios are not reliable indicators of database performance and should not be used as sole criteria to end tuning efforts.
* D (Incorrect):Having I/O less than 10% of DB time is not a definitive indicator to stop tuning. It is essential to consider the overall performance goals and whether they have been met rather than focusing solely on I/O metrics.
References:
* Oracle Database Performance Tuning Guide:Introduction to Performance Tuning
* Oracle Database 2 Day + Performance Tuning Guide:Understanding the Tuning Process
質問 # 43
Examine this statement and its corresponding execution plan:
Which phase introduces the CONCATENATION step?
- A. SQL Transformation
- B. SQL Execution
- C. SQL Semantic Check
- D. SQL Adaptive Execution
- E. SQL Row Source Generation
正解：A
解説：
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
質問 # 44
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 the creation of additional indexes
- C. recommendations regarding the creation of materialized views
- D. recommendations regarding rewriting the SQL statements
- E. recommendations regarding partitioning the tables
正解：B、C
解説：
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
質問 # 45
A Standard Edition production database has performance problems for two hours on the same day each week.
Which tool must you use to diagnose the problem?
- A. Database Replay
- B. Statspack report
- C. AWR Compare Periods report
- D. SQL Performance Analyzer
正解：B
解説：
For a Standard Edition production database, the Statspack tool is available to diagnose performance problems.
The Automatic Workload Repository (AWR) and its related tools like AWR Compare Periods report and SQL Performance Analyzer are features of the Oracle Database Enterprise Edition and are not available in Standard Edition. Database Replay is also a feature of the Enterprise Edition. Statspack is a performance diagnostic tool provided for earlier versions and Standard Editions of the Oracle Database to collect, store, and analyze performance data.
References
* Oracle Database 19c Administrator's Guide - Using Statspack to Diagnose Database Performance Issues
質問 # 46
Multiple sessions are inserting data concurrently into a table that has an LOB column.
At some point in time, one of the sessions cannot find available space in the LOB segment and needs to allocate a new extent.
Which wait event will be raised in the other sessions that need space in the LOB column?
- A. enq: SQ - contention
- B. enq: TX - allocate ITL entry
- C. enq: TM - contention
- D. enq: HW - contention
正解：D
解説：
When sessions concurrently insert data into a table with an LOB column and one session needs to allocate a new extent because it cannot find available space, the wait event associated with this contention is "enq: HW - contention". The HW stands for High Water Mark which is related to space allocation in the database segment.
When asession needs to allocate a new extent, it may raise this wait event in other sessions that are also attempting to allocate space in the same LOB segment.
References
* Oracle Database 19c Reference Guide - enq: HW - contention
質問 # 47
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Oracle 1Z0-084 認定は、プロフェッショナルがOracle Database 19cのパフォーマンスとチューニング管理におけるスキルと知識を向上させる優れた方法です。この認定は、グローバルに認められ、IT業界において貴重な資産と見なされています。1Z0-084 認定を持つプロフェッショナルは、データベースのパフォーマンスを最適化し、システムの可用性を確保し、システムのダウンタイムを削減するという専門知識と信頼性を証明することができます。全体的に、Oracle 1Z0-084 認定は、データベース管理のキャリアを進めたいプロフェッショナルにとって、優れた投資です。
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