DOP-C02 Amazon RDS Performance Insights Practice Question
A company runs a critical application on Amazon RDS for PostgreSQL. The database experiences periodic slowdowns. The team wants to monitor the number of active connections and the query execution time. Which approach is most cost-effective?
⚠ Common exam trap
Candidates often assume Enhanced Monitoring is the most cost-effective because it is free, but it lacks query-level performance data. The key is that Performance Insights tracks execution time natively and is included at no extra cost for the first 7 days, making it the correct choice for this requirement.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Performance Insights and set up CloudWatch alarms on the 'DBLoad' metric.
Performance Insights provides detailed query execution time metrics, enabling monitoring of query performance. It also includes the 'DBLoad' metric which reflects database load from active connections and queries. Combined with CloudWatch alarms, this approach is cost-effective as Performance Insights is included with RDS at no additional cost for up to 7 days of retention (longer retention has a fee). Options A and B are invalid because the CloudWatch agent cannot be installed on RDS instances, and 'QueryExecutionTime' is not a standard CloudWatch metric for RDS. Option D is less suitable for the specific requirement of query execution time; Enhanced Monitoring provides OS-level metrics like processes and memory but does not track query-level execution time.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Install the CloudWatch agent on the RDS instance to collect custom metrics.
Why it's wrong here
RDS is a fully managed service that does not grant shell access or the ability to install custom software such as the CloudWatch agent. The CloudWatch agent is designed for EC2 instances and on-premises servers, where it can collect custom metrics by reading system logs and statistics. Attempting to install it on an RDS instance is impossible from the user side, so this approach is not technically feasible.
- ✗
Use the RDS console to view the 'DatabaseConnections' and 'QueryExecutionTime' metrics.
Why it's wrong here
The RDS console exposes a limited set of CloudWatch metrics like DatabaseConnections, but it does not provide a 'QueryExecutionTime' metric for PostgreSQL—database engine metrics are not available through standard RDS monitoring. Viewing metrics in the console only gives a point-in-time snapshot and does not trigger proactive alerts unless you configure a CloudWatch alarm. Furthermore, without Performance Insights or another query-level tool, you cannot obtain execution-time data from the default RDS metrics.
- ✓
Enable Performance Insights and set up CloudWatch alarms on the 'DBLoad' metric.
Why this is correct
Performance Insights exposes the DBLoad metric, which represents the average number of active sessions and directly reflects query execution workload, and it can be streamed to CloudWatch for alarm creation. Per-query execution time is visible through the top SQL dashboard, allowing you to correlate load spikes with specific queries. The basic retention is included with RDS at no additional cost, making this a cost-effective and fully managed solution for monitoring query performance.
- ✗
Enable Enhanced Monitoring and publish metrics to CloudWatch, then create alarms on relevant metrics.
Why it's wrong here
Enhanced Monitoring provides OS-level metrics such as CPU utilization, memory usage, and disk I/O by running a lightweight agent on the RDS host, but it does not measure database query execution time or per-query load. These metrics help diagnose infrastructure bottlenecks, not query-level performance, so they cannot satisfy the requirement to monitor query execution time. Alarms on these OS metrics would not alert on slow-running queries.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DOP-C02 exam.