SOA-C03 practice question: RDS performance monitoring

Monitoring, Logging, Analysis, Remediation, and Performance Optimization A free question from our original SOA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.

A pet insurer's claims intake uses AWS Lambda functions that write to an Amazon RDS for PostgreSQL DB instance. During a marketing campaign, thousands of functions ran at once and the database rejected new connections with too many clients errors, although CPU stayed below 40 percent. The team wants to absorb these bursts without changing the database engine or the instance size. What should a CloudOps engineer do?

Choose one answer.

A. Create a read replica and point half of the Lambda functions at it so that connections are split across two instances.
B. Raise max_connections in the DB parameter group to the highest value allowed so that the instance accepts every connection.
C. Put an RDS Proxy in front of the DB instance and have the Lambda functions connect to the proxy endpoint instead.
D. Turn on Performance Insights and find the SQL statements that hold connections the longest, then tune them.

Show the answer and explanation

Answer: C

A. Wrong: Read replicas accept only read queries. Claims intake writes to the database, so functions pointed at a replica would fail. Learn more: Working with DB instance read replicas (opens in a new tab)
B. Wrong: Each PostgreSQL connection uses memory, so a much higher limit can exhaust memory under a burst. It treats the symptom instead of reducing the number of connections. Learn more: Parameter groups for Amazon RDS (opens in a new tab)
C. Right: Correct. RDS Proxy keeps a pool of database connections and shares them among many clients. Bursts of short-lived Lambda connections are multiplexed onto fewer database connections. Learn more: Amazon RDS Proxy (opens in a new tab)
D. Wrong: Performance Insights shows where database load comes from and is useful for tuning. It does not limit or share connections, so the burst would still exceed the limit. Learn more: Monitoring DB load with Performance Insights (opens in a new tab)

Explanation

Serverless clients open many short-lived connections, and with low CPU the limit is connections, not compute. RDS Proxy pools and reuses connections so that bursts reach the database as a manageable number. Read replicas cannot take writes, a higher max_connections risks memory, and Performance Insights diagnoses rather than fixes.

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Amazon RDS Proxy

SOA-C03 practice question: RDS performance monitoring

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