1z0-084 Dumps with Practice Exam Questions Answers

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

To produce a consolidated formatted trace file from multiple trace files generated by all clients for a single service, the combination oftrcsessandTKPROFutilities is used. Thetrcsessutility consolidates trace files based on specified criteria such as session, client identifier, or service name. This results in a single trace file that combines the desired tracing information. Next,TKPROFis used to format the output of the trace file generated bytrcsess, providing a readable summary of the trace, including execution counts, execution times, and SQL statement text along with execution plans.

Steps:

• Usetrcsessto combine trace files:
• UseTKPROFto format the consolidated trace file:

References:

• Oracle Database Performance Tuning Guide, 19c
• Oracle Database Utilities, 19c

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 becauseDB_BIG_TABLE_CACHE_PERCENT_TARGETis 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):IncreasingDB_BIG_TABLE_CACHE_PERCENT_TARGETto 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):IncreasingDB_CACHE_SIZEto 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:IncreasingDB_BIG_TABLE_CACHE_PERCENT_TARGETto 50 without adjusting the overall size of the cache might still not be sufficient if theDB_CACHE_SIZEis not large enough to hold the big tables.
• B:SettingDB_KEEP_CACHE_SIZEto at least 50M only specifies a separate buffer pool for objects with the KEEP cache attribute and does not affect Big Table caching.
• E:andF:Changing thePARALLEL_DEGREE_POLICYtoADAPTIVEorAUTOinfluences 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

Monitoring of Database Operations requires that theSTATISTICS_LEVELparameter be set toALLandCONTROL_MANAGEMENT_PACK_ACCESSbe set toDIAGNOSTIC+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

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