The correct answer is to compress the data using a codec like Snappy or Gzip, alongside leveraging Parquet’s columnar format and partitioning by date. This trio directly addresses Athena performance optimization by minimizing the amount of data scanned per query—Parquet stores data column-wise, so Athena reads only the relevant columns, while date partitioning allows the engine to skip entire directories of irrelevant data. Compression further reduces storage footprint and I/O, lowering both scan costs and query latency. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding of how Glue-cataloged S3 data interacts with Athena’s pricing model, which charges per byte scanned. A common trap is assuming more partitions always help, but excessive tiny partitions can actually hurt performance due to metadata overhead. Remember the memory tip: “Parquet, Partition, Compress—the three pillars of Athena success.”
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 company uses AWS Glue to catalog data stored in Amazon S3. The data is in Parquet format and partitioned by date. The company wants to improve query performance in Amazon Athena and reduce costs. Which THREE actions should the company take? (Choose THREE.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Partition the data by date so Athena can use partition pruning.
Using columnar formats like Parquet improves performance and reduces scanned data. Partitioning by date allows Athena to prune partitions. Compressing data reduces storage and scan costs. Converting to JSON would hurt performance. Increasing partition count may help but is not a guarantee. Using Glue DataBrew is for data preparation, not performance optimization.
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.
✗
Convert the data to JSON format for better schema evolution.
Use Glue DataBrew to clean the data before querying.
Why it's wrong here
DataBrew is for data preparation, not performance optimization.
✓
Partition the data by date so Athena can use partition pruning.
Why this is correct
Partition pruning limits the amount of data scanned per query.
Related concept
Read the scenario before looking for a memorised answer.
✓
Ensure the data is in a columnar format like Parquet or ORC.
Why this is correct
Columnar formats improve query performance and reduce data scanned.
Related concept
Read the scenario before looking for a memorised answer.
✓
Compress the data using a codec like Snappy or Gzip.
Why this is correct
Compression reduces storage cost and I/O.
Related concept
Read the scenario before looking for a memorised answer.
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: Partition the data by date so Athena can use partition pruning. — Using columnar formats like Parquet improves performance and reduces scanned data. Partitioning by date allows Athena to prune partitions. Compressing data reduces storage and scan costs. Converting to JSON would hurt performance. Increasing partition count may help but is not a guarantee. Using Glue DataBrew is for data preparation, not performance optimization.
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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