The answer is to increase the number of nodes to 8. This is correct because adding nodes directly addresses the root cause of slow queries tied to high disk usage: when a Redshift cluster’s disk is 85% full, the remaining space is too fragmented for efficient I/O, forcing the query engine to spill to disk and degrade performance. By scaling out from 4 to 8 dc2.large nodes, you distribute the data across more slices, increasing I/O parallelism and reducing the per-node disk pressure. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding that Redshift’s performance bottlenecks from high disk usage are best solved by scaling compute and storage together, not by vacuuming or redesigning table schemas mid-operation. A common trap is choosing VACUUM, but that only reclaims interleaved sort space, not raw capacity. Memory tip: “Disk full? Scale out—don’t clean out.”
DEA-C01 Data Operations and Support Practice Question
This DEA-C01 practice question tests your understanding of data operations and support. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 is monitoring a Redshift cluster that is experiencing slow query performance. The cluster has 4 dc2.large nodes. The engineer notices that disk space usage is at 85% across all nodes. Which action would MOST likely improve query performance?
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
✓
Increase the number of nodes to 8.
Option D is correct because adding more nodes distributes data and improves I/O parallelism. Option A is wrong because vacuum reclaims space but does not help if disk usage is high due to data volume. Option B is wrong because DISTKEY and SORTKEY changes are design-time decisions. Option C is wrong because compression is already applied at load time.
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.
✗
Change the table design to use DISTKEY and SORTKEY.
Why it's wrong here
Table design changes require table recreation and do not immediately reduce disk usage.
✗
Enable compression on all columns.
Why it's wrong here
Compression is typically set at table creation; existing tables may already be compressed.
✓
Increase the number of nodes to 8.
Why this is correct
Adding nodes increases disk capacity and I/O throughput, reducing disk pressure and improving query performance.
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.
✗
Run the VACUUM command to reclaim space.
Why it's wrong here
VACUUM cleans up deleted rows but does not reduce overall data volume.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which DEA-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.
Data Operations and Support — This question tests Data Operations and Support — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the number of nodes to 8. — Option D is correct because adding more nodes distributes data and improves I/O parallelism. Option A is wrong because vacuum reclaims space but does not help if disk usage is high due to data volume. Option B is wrong because DISTKEY and SORTKEY changes are design-time decisions. Option C is wrong because compression is already applied at load time.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-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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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.
Question Discussion
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