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Oracle 1Z0-084 exam is a valuable certification for IT professionals who work with Oracle Database 19c. Certification in this area demonstrates a high level of expertise and can help individuals advance their careers and increase their earning potential. By passing the exam, candidates demonstrate their ability to optimize database performance, which is a critical skill in today's data-driven business environment.
If you are a database professional looking to validate your skills in performance and tuning management, then the Oracle 1Z0-084 exam is the right choice for you. Oracle Database 19c Performance and Tuning Management certification not only enhances your credibility in the industry but also opens up new career opportunities. With the right preparation and practice, you can pass 1z1-084 exam and join the elite group of Oracle certified professionals.
Oracle 1Z0-084 Certification Exam is a challenging exam that requires a strong understanding of the Oracle Database 19c and its performance management features. 1z1-084 exam consists of 80 multiple-choice questions that must be completed within a two-hour time frame. To pass the exam, candidates must score at least 63% on the exam. 1z1-084 exam can be taken at any authorized testing center or through an online proctoring service.
NEW QUESTION # 29
For which two actions can SQL Performance Analyzer be used to assess the impact of changes to SQL performance?
- A. storage, network, and interconnect changes
- B. database consolidation for pluggable databases (PDBs)
- C. operating system and hardware migrations
- D. operating system upgrades
- E. changes to database initialization parameters
Answer: B,E
Explanation:
SQL Performance Analyzer (SPA) can be used to assess the impact of different types of changes on SQL performance. These changes can include database initialization parameters, which can significantly affect how SQL statements are executed and therefore their performance. SPA allows you to capture a workload before and after the change and compare the performance of each SQL statement.
Database consolidation, including moving to pluggable databases (PDBs), can also affect SQL performance.
SPA can analyze the SQL workload to see how consolidation impacts performance, by comparing metrics such as elapsed time and CPU time before and after the consolidation.
References:
* Oracle Database SQL Tuning Guide, 19c
* Oracle Database Performance Tuning Guide, 19c
NEW QUESTION # 30
Examine this command:
What is the maximum number of baselines generated by this command that you can have at any given time?
- A. 0
- B. 1
- C. 2
- D. 3
Answer: B
Explanation:
TheDBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATEprocedure is used to create a repeating baseline template in the Automatic Workload Repository (AWR). This template will generate baselines for a specified duration of time on a repeating schedule. Theparameters of the CREATE_BASELINE_TEMPLATEprocedure include the start and end times, as well as the day of the week and hour in the day when the baseline should be captured.
Given that the command specifies a repeating baseline every Monday at 5 PM with a duration of 3 hours and it expires after 30 days, the number of baselines generated by this command that you can have at any given time depends on how many Mondays fall within the most recent 30-day period.
Since the maximum number of Mondays that can occur within any 30-day period is 5 (four to five weeks), but considering the baseline has a duration of 3 hours and starts every Monday at 5 PM, only one baseline for each Monday can exist at a time. However, since baselines are preserved for 30 days, you could have multiple instances of Monday baselines preserved at a time.
* A (Incorrect):There can be more than one baseline at a time because the template will generate a baseline for every Monday during the 30-day expiration period.
* B (Incorrect):There will be more than three baselines because the template creates a baseline for every Monday within the 30-day expiration period.
* C (Correct):Over a 30-day period, considering the duration of the baselines and their frequency, you could have up to a maximum of 52 baselines if you consider the entire year.
* D (Incorrect):There is no option that restricts the number of baselines to 5 specifically, the answer relies on the calculation of how many baselines can exist over a period of time considering their expiration.
References:
* Oracle Database PL/SQL Packages and Types Reference:DBMS_WORKLOAD_REPOSITORY
NEW QUESTION # 31
Which statement is true about DB time in V$$YS_TIME_MODEL?
- A. DB tine excludes the time spent waiting for a CPU in the operating system run queue.
- B. DB time is organized as a simple list of statistics and any time period is attributable to only one statistic.
- C. DB time includes the time spent executing the RMAN backup and restore command.
- D. DB time can be many times greater than the elapsed time since the database instance started.
Answer: D
Explanation:
DB time includes the time spent on user and background processes. It can be greater than the elapsed time because it accumulates the active time of all the processes. For example, if two sessions are each active for 2 seconds at the same time, DB time would accumulate 4 seconds, while the elapsed time would be only 2 seconds.References:
* Oracle Database Performance Tuning Guide, 19c
* Oracle Database Reference, 19c
NEW QUESTION # 32
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. Collect a new set of statistics on PRODUCT, CUSTOMERS, and SALES because the current stats are inaccurate.
- C. Replace the FETCH FIRST clause with ROWNUM to enable the use of an index on SALES.
- D. 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.
- 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 # 33
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 improves performance for queries joining several tables using bloom filter joins.
- D. It can improve OLTP workload performance by avoiding the use of indexes.
- E. It does not improve performance for queries that use join groups on columns from different tables.
- F. It does not improve performance for queries using user-defined virtual column results.
Answer: A,C,D
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 # 34
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 the SALES table using the columns in IX_SALES_TIME_ID as the hash partitioning key.
- C. Re-create index IX_SALES_TIME_ID using ADVANCED COMPRESSION.
- D. Re-create the SALES table sorted in order of index IX_SALES_TIME_ID.
Answer: C
Explanation:
Given that index range scan operations onIX_SALES_TIME_IDare slower due to an increase in buffer gets, the aim is to improve the efficiency of the index access. In this scenario:
* B (Correct):Re-creating the index usingADVANCED COMPRESSIONcan reduce the size of the index, which can lead to fewer physical reads (reduced I/O) and buffer gets when the index is accessed, as more of the index can fit into memory.
The other options would not be appropriate because:
* A (Incorrect):Re-creating theSALEStable sorted in order of the index might not address the issue of excessive buffer gets. Sorting the table would not improve the efficiency of the index itself.
* C (Incorrect):Using the columns inIX_SALES_TIME_IDas a hash partitioning key for theSALES table is more relevant to data distribution and does not necessarily improve index scan performance.
* D (Incorrect):Hash partitioning the index is generally used to improve the scan performance in a parallel query environment, but it may not reduce the number of buffer gets in a single-threaded query environment.
References:
* Oracle Database SQL Tuning Guide:Managing Indexes
* Oracle Database SQL Tuning Guide:Index Compression
NEW QUESTION # 35
Which three statements are true about tuning dimensions and details of v$sys_time_model and DB time?
- A. DB Time accounts for all time used by background processes and user sessions.
- B. Systems in which CPU time is dominant need more tuning that those in which WAIT TIME is dominant.
- C. Parse Time Elapsed accounts for successful soft and hard parse operations only.
- D. The proportion of WAIT TIME to CPU TIME always increases with increased system load.
- E. When WAIT TIME is high, instance tuning may improve performance.
- F. 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.
Answer: A,E,F
Explanation:
A: Statspack is a performance diagnostic tool that can help identify high CPU usage issues. High CPU time may indicate that SQL statements need to be tuned for better performance.
D: High wait times can often be reduced by instance tuning, such as adjusting database parameters or improving I/O performance.
F: DB Time is a cumulative time metric that includes the time spent by both user sessions and background processes executing database calls.References:
* Oracle Database Performance Tuning Guide, 19c
* Oracle Database Concepts, 19c
NEW QUESTION # 36
Which two types of performance problems are reported by ADDM for PDBS?
- A. Excessive checkpoint writes
- B. User I/O waits
- C. SGA sizing issues
- D. I/O capacity limits
- E. Top SQL statements
Answer: B,D
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 # 37
Examine this statement and its corresponding execution plan:
Which phase introduces the CONCATENATION step?
- A. SQL Semantic Check
- B. SQL Adaptive Execution
- C. SQL Transformation
- D. SQL Row Source Generation
- E. SQL Execution
Answer: C
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 # 38
You need to transport performance data from a Standard Edition to an Enterprise Edition database. What is the recommended method to do this?
- A. Export the data by using expdp from the ftatspack repository and import it by using impdp into the AWR repository.
- B. Export the data by using the exp utility and parameter file spuexp.par from the Statspack repository and import it by using imp into a dedicated Statspack schema on the destination.
- C. Export the data by using the expdp utility and parameter file spuexp.par from the Statspack repository and import it by using impdp into Export the data by using expdp from the Statspack repository and import it by using impdp into the AWR repository.
- D. Export the data by using expdp from Statspack and import it by using
$ORACLE_HOME/rdbms/admin/awrload into the AWRrepository.
Answer: B
Explanation:
To transport performance data from an Oracle Database Standard Edition, which uses Statspack, to an Enterprise Edition database, which uses AWR, you must consider the compatibility of data structures and repository schemas between these tools. The recommended method is:
* D (Correct):Export the data using theexputility with a parameter file appropriate for Statspack (like spuexp.par) from the Statspack repository and import it into a dedicated Statspack schema on the destination. Since Statspack and AWR use different schemas, it's not recommended to import Statspack data directly into the AWR repository.
The other options are incorrect because:
* A (Incorrect):expdpis not designed to export from Statspack, andawrloadis intended for loading from an AWR export file, not a Statspack export.
* B (Incorrect):Althoughexpdpandimpdpare used for exporting and importing data, the AWR repository schema is different from the Statspack schema, so importing Statspack data directly into the AWR repository is not recommended.
* C (Incorrect):Usingexpdpto export from Statspack and then importing directly into the AWR repository is not the correct approach due to the schema differences between Statspack and AWR.
References:
* Oracle Database Performance Tuning Guide:Migrating from Statspack to AWR
NEW QUESTION # 39
Which two actions can cause invalidation or loss of one or more results in the SQL Query Result Cache?
- A. result_cache_max_size is set dynamically to 0.
- B. A request was made by the RCBG background of a non-RAC database.
- C. Decreasing the value set for RESULT_CACHE_REMOTE_EXPIRATION.
- D. One or more results were aged out of the result cache.
- E. 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.
Answer: A,D
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 # 40
You want to reduce the amount of db file scattered read that is generated in the database.You execute the SQL Tuning Advisor against the relevant workload. Which two can be part of the expected result?
- A. recommendations regarding the creation of additional indexes
- B. recommendations regarding the creation of materialized views
- C. recommendations regarding partitioning the tables
- D. recommendations regarding rewriting the SQL statements
- E. recommendations regarding the creation of SQL Patches
Answer: A,B
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 # 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 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 2 minutes for each user call.
Answer: A
Explanation:
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.
NEW QUESTION # 42
Which two options are part of a Soft Parse operation?
- A. SQL Optimization
- B. Syntax Check
- C. SQL Row Source Generation
- D. Shared Pool Memory Allocation
- E. Semantic Check
Answer: E
NEW QUESTION # 43
Examine these statements and output:
What parameter change activates the generation and use of SQL Plan Directives7
- A. optimizer_capture_sql_plan_baselines_TRUE
- B. optimizer_adaptive_statistics = TRUE
- C. optimizer_adaptive_plans=TRUE
- D. optimizer_dynamic_sampling=11
- E. optimizer_features_enable=12.2.0.1
Answer: B
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 # 44
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