- A
Use of S3 Transfer Acceleration.
Why wrong: S3 Transfer Acceleration improves upload speed, not read performance, so it does not factor into read performance issues.
- B
Use of S3 Select to retrieve only a subset of data.
S3 Select can retrieve only a subset of data (e.g., using SQL expressions), reducing data scanned and improving read performance.
- C
Use of S3 Object Lock.
Why wrong: S3 Object Lock prevents object deletion or overwrites; it does not affect read performance.
- D
Average object size in S3 bucket.
Average object size affects read performance because larger objects allow more efficient parallel reads and better throughput.
- E
Data stored in compressed format (e.g., GZIP, Snappy).
Compressed data reduces the amount of data transferred from S3, improving read performance.
DEA-C01 S3 Select 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. A key principle to apply: s3 Select. 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 Amazon EMR to run Spark jobs on data stored in Amazon S3. The data engineer notices that the jobs are running slower than expected. The engineer suspects that the S3 storage class might be affecting performance. Which THREE factors can impact read performance from S3? (Choose three.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Use of S3 Select to retrieve only a subset of data.
Options B, D, and E are correct. B: S3 Select can retrieve only a subset of data, reducing the amount scanned and improving read performance. D: Larger average object sizes allow better throughput by leveraging parallel requests and reducing overhead. E: Storing data in compressed formats reduces the amount of data transferred, improving read performance. Option A is incorrect because S3 Transfer Acceleration is designed to improve upload speed over long distances, not read performance. Option C is incorrect because S3 Object Lock prevents object deletion or overwrite but does not affect read performance.
Key principle: S3 Select
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use of S3 Transfer Acceleration.
Why it's wrong here
S3 Transfer Acceleration improves upload speed, not read performance, so it does not factor into read performance issues.
- ✓
Use of S3 Select to retrieve only a subset of data.
Why this is correct
S3 Select can retrieve only a subset of data (e.g., using SQL expressions), reducing data scanned and improving read performance.
Related concept
S3 Select
- ✗
Use of S3 Object Lock.
Why it's wrong here
S3 Object Lock prevents object deletion or overwrites; it does not affect read performance.
- ✓
Average object size in S3 bucket.
Why this is correct
Average object size affects read performance because larger objects allow more efficient parallel reads and better throughput.
Related concept
S3 Select
- ✓
Data stored in compressed format (e.g., GZIP, Snappy).
Why this is correct
Compressed data reduces the amount of data transferred from S3, improving read performance.
Related concept
S3 Select
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common mistake is thinking S3 Transfer Acceleration improves read performance, but it only speeds up uploads.
Detailed technical explanation
How to think about this question
Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- S3 Select
- Average object size
- Data compression
TExam Day Tips
- 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
S3 Select
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.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
What to study next
Got this wrong? Here's your next step.
Review s3 Select, then practise related DEA-C01 questions on the same topic to reinforce the concept.
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Data Operations and Support — study guide chapter
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FAQ
Questions learners often ask
What does this DEA-C01 question test?
Data Operations and Support — This question tests Data Operations and Support — S3 Select.
What is the correct answer to this question?
The correct answer is: Use of S3 Select to retrieve only a subset of data. — Options B, D, and E are correct. B: S3 Select can retrieve only a subset of data, reducing the amount scanned and improving read performance. D: Larger average object sizes allow better throughput by leveraging parallel requests and reducing overhead. E: Storing data in compressed formats reduces the amount of data transferred, improving read performance. Option A is incorrect because S3 Transfer Acceleration is designed to improve upload speed over long distances, not read performance. Option C is incorrect because S3 Object Lock prevents object deletion or overwrite but does not affect read performance.
What should I do if I get this DEA-C01 question wrong?
Review s3 Select, then practise related DEA-C01 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
S3 Select
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Last reviewed: Jun 20, 2026
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.
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