This DEA-C01 practice question tests your understanding of data store management. 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 designing a data lake on Amazon S3. Data is ingested from multiple sources in JSON format. The engineer needs to optimize query performance for Amazon Athena while minimizing storage costs. Which storage strategy should the engineer use?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Convert data to Parquet format and partition by date.
Parquet is a columnar format that reduces storage size and improves query performance in Athena. Partitioning by date further optimizes queries that filter by date. Option B is correct. Option A: storing as raw JSON with no partitioning leads to higher costs and slower queries. Option C: using Glacier for hot data adds retrieval latency and is not suitable for frequent queries. Option D: storing in a single bucket with no structure causes full scans.
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.
✗
Store data as CSV files in a single S3 bucket without prefixes.
Why it's wrong here
CSV is not as efficient as Parquet; no partitioning causes poor performance.
✓
Convert data to Parquet format and partition by date.
Why this is correct
Parquet is columnar and compressed; partitioning improves query performance.
Related concept
Read the scenario before looking for a memorised answer.
✗
Store data as JSON files in a single prefix without partitioning.
Why it's wrong here
JSON is not optimized for Athena; no partitioning leads to full scans.
✗
Store compressed JSON files in Amazon S3 Glacier.
Why it's wrong here
Glacier is for archival, not frequent querying.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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 Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Convert data to Parquet format and partition by date. — Parquet is a columnar format that reduces storage size and improves query performance in Athena. Partitioning by date further optimizes queries that filter by date. Option B is correct. Option A: storing as raw JSON with no partitioning leads to higher costs and slower queries. Option C: using Glacier for hot data adds retrieval latency and is not suitable for frequent queries. Option D: storing in a single bucket with no structure causes full scans.
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.
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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