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 running an Amazon Athena query that scans a large amount of data in Amazon S3, resulting in high costs. The data is stored in Parquet format in a partitioned table. Which strategy would be MOST effective in reducing the amount of data scanned?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Ensure the query includes a WHERE clause that filters on partition columns.
Option D is correct because using a WHERE clause on partition columns allows Athena to use partition pruning, scanning only the relevant partitions. Option A is incorrect because converting from Parquet to CSV would increase data scanned. Option B is incorrect because increasing the number of partitions without querying on them does not reduce scan. Option C is incorrect because compressing with GZIP reduces storage size but Athena still decompresses and scans the full data if no partition pruning is used.
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.
✓
Ensure the query includes a WHERE clause that filters on partition columns.
Why this is correct
Partition pruning reduces the amount of data scanned.
Related concept
Read the scenario before looking for a memorised answer.
✗
Convert the Parquet files to CSV format and apply GZIP compression.
Why it's wrong here
CSV is less efficient than Parquet and increases scan.
✗
Use S3 Intelligent-Tiering storage class to reduce storage costs.
Why it's wrong here
Storage class does not affect query scan size.
✗
Increase the number of partitions by adding more partition columns.
Why it's wrong here
More partitions alone do not reduce scan without filtering.
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 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: Ensure the query includes a WHERE clause that filters on partition columns. — Option D is correct because using a WHERE clause on partition columns allows Athena to use partition pruning, scanning only the relevant partitions. Option A is incorrect because converting from Parquet to CSV would increase data scanned. Option B is incorrect because increasing the number of partitions without querying on them does not reduce scan. Option C is incorrect because compressing with GZIP reduces storage size but Athena still decompresses and scans the full data if no partition pruning is used.
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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