DOP-C02 Incident and Event Response Practice Question
A company uses Amazon RDS for MySQL with Multi-AZ deployment. The database experiences a sudden spike in connections, causing the application to timeout. The DevOps engineer notices that the 'DatabaseConnections' metric is high, but the 'CPUUtilization' is low. Which THREE actions should the engineer take to diagnose the issue?
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
✓
Check the 'max_connections' parameter in the DB parameter group and increase it if needed.
Checking the 'max_connections' parameter in the DB parameter group reveals whether the connection spike is hitting the configured limit. Increasing it temporarily can alleviate timeouts while investigating the root cause. Option D is correct because enabling the general_log and setting log_output to TABLE or FILE captures connection attempts, helping identify the source of connections (e.g., a surge from a specific application or an attack). Option E is correct because Performance Insights provides visibility into active sessions and top SQL, allowing the engineer to pinpoint which queries or connections are contributing to the spike. Option B is incorrect because adding a read replica offloads read traffic, not connections; the primary instance still handles all write connections. Option C is incorrect because scaling up the DB instance class primarily addresses CPU, memory, and I/O capacity, but does not directly increase the connection limit; it is better to first diagnose with logging and Performance Insights before resizing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Check the 'max_connections' parameter in the DB parameter group and increase it if needed.
Why this is correct
The max_connections parameter in the RDS parameter group defines the hard ceiling of allowed simultaneous client connections; if this limit is being hit, legitimate application requests are rejected with 'too many connections'. Reviewing this value against your connection pool settings and raising it if it's legitimately too low can provide immediate relief, but doing so without understanding why the number of connections jumped can exhaust memory or threads because each connection consumes resources. Also, changing the parameter group may require a reboot depending on whether it's a static or dynamic parameter, so monitor after applying.
- ✗
Add a read replica to offload read traffic.
Why it's wrong here
Adding a read replica does not reduce the connection count on the primary instance because all write transactions and most connection management operations (like authentication) still go to the primary. Even if you route read traffic to the replica, the application must still hold connections to the primary for writes, and a replica has its own connection limit. Therefore, this action does not address an existing connection spike; it only helps offload CPU/IO from read-heavy workloads, not the connection logjam.
- ✗
Scale up the DB instance class to handle more connections.
Why it's wrong here
Scaling up the DB instance class improves CPU, memory, and network capacity, but it does not inherently increase the max_connections value unless your parameter group has a formula based on DBInstanceClassMemory. Even if the connection limit rises with the larger instance, the underlying cause of the connection spike (e.g., a misconfigured connection pool or a hung application) remains untouched, so the issue will likely recur. Additionally, a scaling operation on a Multi-AZ RDS instance triggers a failover or downtime, which can exacerbate connection errors if applications aren't configured for automatic reconnection.
- ✓
Enable the 'general_log' and 'log_output' parameters to capture connection attempts.
Why this is correct
Enabling the general_log with log_output=TABLE or FILE on RDS MySQL records every connection attempt, including the source host, user, and timestamp, which lets you correlate the spike with specific application servers, IPs, or times. This is the fastest way to identify whether the surge is malicious, a connection leak in a service, or an artifact of a failover/reboot. Be aware that the general log adds I/O overhead, so it should be enabled temporarily and disabled once enough data is captured.
- ✓
Enable Performance Insights and review the top SQL queries and sessions.
Why this is correct
Performance Insights provides a visual dashboard that shows database load (DB Load) broken down by waits, SQL statements, and host identifiers, allowing you to see which queries are active and how many sessions are holding them open. If a long-running query or an uncommitted transaction is holding locks, you can see active sessions piling up and identify the root cause rather than just treating the symptom. This is a read-mostly diagnostic that doesn't add significant overhead and helps pinpoint whether the connection spike is tied to a particular query pattern or a specific application instance.
Go deeper
Related to this question
About these practice questions
One of 1,487 original DOP-C02 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on DOP-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company runs a production database on Amazon RDS for MySQL. The database experiences a sudden spike in connections, causing the application to time out. The DevOps team needs to diagnose the issue quickly. Which combination of actions should be taken? (Choose two.)
medium- ✓ A.Check CloudWatch metrics for DatabaseConnections and CPUUtilization.
- B.Immediately scale up the RDS instance to handle the load.
- C.Analyze VPC Flow Logs to identify the source IPs of connections.
- D.Use the RDS console to view the number of active connections per user.
- ✓ E.Enable Performance Insights and review the top SQL statements.
Why A: CloudWatch metrics such as DatabaseConnections and CPUUtilization provide real-time monitoring to quickly identify anomalies. Option E is correct because Performance Insights reveals the top SQL statements consuming resources, helping pinpoint the root cause of the connection spike. Option B is incorrect because scaling up is a reactive mitigation, not a diagnostic action. Option C is incorrect because VPC Flow Logs capture network-level traffic but do not show database connection counts or details. Option D is incorrect because the RDS console displays aggregate connection metrics, not per-user connection details.
JA
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.