Oracle 1Z0-084 Exam Dumps

For this SQL statement and output, we can analyze the EVENT column 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.

Oracle Database Reference, 19c

Oracle Wait Events Documentation

The DBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGS procedure allows setting attributes related to AWR snapshots. While the interval setting controls the frequency of snapshot generation, purging them is a separate process that can be managed either automatically (with retention settings) or manually. Reference:

Oracle Database PL/SQL Packages and Types Reference, 19c

Oracle Multitenant Administrator's Guide, 19c

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. Reference:

Oracle Database Performance Tuning Guide, 19c

Oracle Database Reference, 19c

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.

Oracle Database SQL Tuning Guide, 19c

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 ADVANCED is 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: While COLUMN STORE COMPRESS FOR QUERY HIGH and ROW STORE COMPRESS are both valid compression types, COLUMN STORE COMPRESS FOR QUERY HIGH applies to the In-Memory column store and is not available in all versions and editions, and ROW STORE COMPRESS is less advanced than ROW STORE COMPRESS ADVANCED.

Oracle Database Concepts Guide: Table Compression

Oracle Database Performance Tuning Guide: Row Compression