The answer is that the cluster has fewer nodes, reducing parallelism. Redshift RA3 nodes separate compute from managed storage, but query performance still depends on the number of nodes available to distribute work across slices. When you move from 10 DC2.large nodes to 4 RA3.xlarge nodes, you cut the node count by more than half, which directly limits the degree of parallelism for query execution, even though each RA3 node has more compute capacity. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding that RA3’s architecture does not eliminate the need for sufficient node count to maintain parallel processing; a common trap is assuming RA3’s managed storage automatically compensates for fewer nodes. Remember the memory tip: “Fewer nodes, fewer hands on deck”—parallelism scales with node count, not just node size.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. 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 warehouse team is migrating from Amazon Redshift to Amazon Redshift RA3 nodes. The current cluster uses 10 DC2.large nodes. The new cluster will use 4 RA3.xlarge nodes. After the migration, the team notices that query performance is significantly slower. Which factor is the MOST likely cause of the performance degradation?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The cluster has fewer nodes, reducing parallelism.
Option A is correct because RA3 nodes use managed storage and compute is separate; fewer nodes reduce parallel processing capability. Option B is incorrect because RA3 nodes are designed for large data. Option C is incorrect because RA3 nodes have managed storage; disk space is not the issue. Option D is incorrect because the number of slices per node is lower in RA3, but the primary factor is fewer nodes.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The data distribution style is set to EVEN instead of KEY.
Why it's wrong here
Distribution style affects performance but is not the most likely cause.
✗
The cluster does not have enough disk space for the workload.
Why it's wrong here
RA3 uses managed storage and does not require local disk sizing.
✓
The cluster has fewer nodes, reducing parallelism.
Why this is correct
RA3 nodes separate compute and storage; fewer compute nodes reduce parallelism.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
RA3 nodes are not optimized for large datasets.
Why it's wrong here
RA3 nodes are optimized for large datasets with managed storage.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The cluster has fewer nodes, reducing parallelism. — Option A is correct because RA3 nodes use managed storage and compute is separate; fewer nodes reduce parallel processing capability. Option B is incorrect because RA3 nodes are designed for large data. Option C is incorrect because RA3 nodes have managed storage; disk space is not the issue. Option D is incorrect because the number of slices per node is lower in RA3, but the primary factor is fewer nodes.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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