A business that specializes in internet advertising is developing an application that will show adverts to its customers. The program stores data in an Amazon DynamoDB database. Additionally, the application caches its reads using a DynamoDB Accelerator (DAX) cluster. The majority of reads come via the GetItem and BatchGetItem queries. The application does not need consistency of readings.
The application cache does not behave as intended after deployment. Specific extremely consistent queries to the DAX cluster are responding in several milliseconds rather than microseconds.
How can the business optimize cache behavior in order to boost application performance?

1. A. Increase the size of the DAX cluster.
2. B. Configure DAX to be an item cache with no query cache
3. C. Use eventually consistent reads instead of strongly consistent reads.
4. D. Create a new DAX cluster with a higher TTL for the item cache.

Correct Answer: C

A database specialist needs to configure an Amazon RDS for MySQL DB instance to close non-interactive connections that are inactive after 900 seconds.
What should the database specialist do to accomplish this task?

1. A. Create a custom DB parameter group and set the wait_timeout parameter value to 900. Associate the DB instance with the custom parameter group.
2. B. Connect to the MySQL database and run the SET SESSION wait_timeout=900 command.
3. C. Edit the my.cnf file and set the wait_timeout parameter value to 900. Restart the DB instance.
4. D. Modify the default DB parameter group and set the wait_timeout parameter value to 900.

Correct Answer: A
https://aws.amazon.com/fr/blogs/database/best-practices-for-configuring-parameters-for-amazon-rds-for-mysql- "You can set parameters globally using a parameter group. Alternatively, you can set them for a particular session using the SET command."
https://aws.amazon.com/blogs/database/best-practices-for-configuring-parameters-for-amazon-rds-for-mysql-pa