Oracle 1Z0-084 Exam Questions

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. Reference:

Oracle Database Concepts, 19c

Oracle Database SQL Tuning Guide, 19c

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 the RESULT_CACHE_MAX_SIZE parameter 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.

Oracle Database Performance Tuning Guide, 19c

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.

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

The production phase of the application lifecycle is often managed reactively. While proactive measures and performance tuning are essential, unforeseen issues can arise in production that require immediate attention and resolution. Reactive management involves monitoring performance and responding to issues as they occur, ensuring the application maintains acceptable performance levels for end-users.

Reference

Oracle Database 19c Performance Tuning Guide - Reactive Tuning

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. Reference:

Oracle Database Performance Tuning Guide, 19c

Oracle Database Concepts, 19c