Queries on the SALES table frequently use the PROD_ID and COST_ID columns together in the WHERE clause. Examine the command:

Which three statements are true about executing this command?

• A. It improves the cardinality estimates when both the PROD_ID and CUST_ID columns are used in the WHERE clause.
• B. It creates a virtual column for the column group (PROD_ID and CUST_ID).
• C. It improves the selectivity estimates of a single predicate in the WHERE clause.
• D. It creates extended statistics for the column group (PROD_ID and CUST_ID).
• E. It gathers individual column statistics for the PROD_ID and CUST_ID columns.

Your database supports an OLTP workload.
An application frequently performs update operations on an indexed column of a table; some bulk delete and insert operations are also performed.
The table is created in a locally managed tablespace with manual segment space management.
A user complains about poor response time when querying the table.
The queries mostly perform index range scans.
You notice a high number of buffer busy waits and contention on segment headers.
Which three would you investigate further to diagnose the poor response time?

• A. Check for freelist contention.
• B. Check the size of the large pool.
• C. Check the size of the shared pool.
• D. Check table blocks for migrated or chained rows.
• E. Chick whether the indexes have only a few entries per block.

You want to capture AWR data to monitor performance variation every Monday between 9:00 AM and 12:00 PM for three months and automatically remove the older AWR data every fortnight.
How would you achieve this? (Choose the best answer.)

• A. Create database services and make sure that user connections use them to connect to the database instance.
• B. Create AWR baselines.
• C. Create repeating baseline templates.
• D. Create a single baseline template.
• E. Create SQL plan baselines.

To investigate the slow response time of queries on the TRANS table, you gathered the table statistics and executed the query:

The table is stored in a tablespace that has Automatic Segment Space Management (ASSM) enabled. The tablespace is created with a standard block size of 8192 bytes.
Which three can be reasons for the slow response time of the queries? (Choose three.)

• A. Row size is too large to fit into a single block during insert operations.
• B. Row moves from one data block to another data block because the row grows too large to fit in the original block.
• C. The value of PCTUSED is set to a value lower than the default, causing row chaining.
• D. The value of PCTFREE is set to a value lower than the default, causing row chaining.
• E. The table is subject to frequent insert, update, and delete DML activity leading to sparsely populated blocks.

You are administrating a database that supports a DSS workload. Syntactically similar queries using joins and aggregate functions are frequently executed by users to fetch data from remote databases by using database links.
Which three tasks should you perform to improve the performance of these queries?

• A. Ensure that the RESULT_CACHE_MAX_SIZE parameter is set to a nonzero value on the local database instance.
• B. Ensure that the RESULT_CACHE_MODE parameter is set to FORCE for remote database instances.
• C. Ensure that the RESULT_CACHE_MAX_SIZE parameter is set to a nonzero value on the remote database instance.
• D. Ensure that the RESULT_CACHE_MAX_RESULT parameter is set to 100.
• E. Ensure that the RESULT_CACHE_MAX_MODE parameter is set to FORCE for the local instance.
• F. Ensure that the RESULT_CACHE_MAX_SIZE parameter is set to a nonzero value on both the local and remote database instances.
• G. Ensure that the RESULT_CACHE_REMOTE_EXPIRATION parameter is set to a nonzero value for the local instance.