Quick Answer
The answer is ReadLatency, WriteLatency, and CPUUtilization. These three CloudWatch metrics are most useful for monitoring RDS PostgreSQL performance because they directly capture the database’s responsiveness to queries and its underlying resource pressure. ReadLatency and WriteLatency measure the average time taken for I/O operations, which is critical for identifying storage bottlenecks or poorly optimized queries, while CPUUtilization reveals whether the instance is being overwhelmed by compute-heavy workloads, often signaling inefficient SQL or the need for a larger instance class. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your ability to distinguish between metrics that reflect actual user-facing performance (latency) versus those that indicate resource saturation (CPU), and a common trap is choosing DiskQueueDepth or FreeableMemory instead, which are more relevant for storage health or memory pressure. Remember the mnemonic “L-C-P” for Latency, CPU, and Performance—if you monitor these three, you’ll catch the most common RDS PostgreSQL slowdowns.
This DEA-C01 practice question tests your understanding of data operations and support. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A data engineer needs to monitor the performance of an RDS for PostgreSQL database. Which THREE CloudWatch metrics are most useful for this purpose?
CPUUtilization
Indicates compute load.
DatabaseConnections
Helps identify connection bottlenecks.
FreeStorageSpace
Why wrong: Indicates storage capacity, not performance.
NetworkThroughput
Why wrong: Measures network traffic, not database performance.
ReadLatency / WriteLatency
Measures I/O performance.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
CPUUtilization
CPUUtilization is a critical metric for monitoring RDS for PostgreSQL because high CPU usage can indicate inefficient queries, insufficient instance size, or contention. Sustained high CPU can lead to performance degradation and increased query latency, making it essential for capacity planning and troubleshooting.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
CPUUtilization
Why this is correct
Indicates compute load.
Related concept
Read the scenario before looking for a memorised answer.
DatabaseConnections
Why this is correct
Helps identify connection bottlenecks.
Related concept
Read the scenario before looking for a memorised answer.
FreeStorageSpace
Why it's wrong here
Indicates storage capacity, not performance.
NetworkThroughput
Why it's wrong here
Measures network traffic, not database performance.
ReadLatency / WriteLatency
Why this is correct
Measures I/O performance.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse storage metrics (like FreeStorageSpace) with performance metrics, or assume NetworkThroughput is a performance indicator, when in fact latency and CPU metrics directly reflect query execution health.
Detailed technical explanation
RDS for PostgreSQL exposes these metrics via the Enhanced Monitoring feature, which provides OS-level metrics in addition to CloudWatch. CPUUtilization reflects the percentage of CPU consumed by the database engine and OS processes, while ReadLatency/WriteLatency measure the average time for I/O operations (in milliseconds) at the EBS volume level, which can reveal storage bottlenecks. DatabaseConnections tracks the number of client connections, which is critical because PostgreSQL uses a process-per-connection model, and excessive connections can exhaust memory or cause context-switching overhead.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
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FAQ
Data Operations and Support — This question tests Data Operations and Support — Read the scenario before looking for a memorised answer..
The correct answer is: CPUUtilization — CPUUtilization is a critical metric for monitoring RDS for PostgreSQL because high CPU usage can indicate inefficient queries, insufficient instance size, or contention. Sustained high CPU can lead to performance degradation and increased query latency, making it essential for capacity planning and troubleshooting.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This DEA-C01 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 DEA-C01 exam.
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