- A
The query result location uses a bucket with default encryption enabled.
Why wrong: Default encryption on the output bucket is not a common cause of failure; Athena can write to encrypted buckets as long as the role has appropriate decrypt permissions.
- B
The SQL query syntax is incorrect.
Why wrong: Incorrect SQL syntax can cause a query failure, but it typically produces a syntax error message, and is less likely than a permissions issue in this general scenario.
- C
The IAM role used does not have permissions to write to S3.
The IAM role used by Athena must have s3:PutObject permission for the output bucket. Lack of permissions is a frequent and common cause of query failures.
- D
The output S3 bucket specified in the query result configuration already exists.
Why wrong: Athena does not require the output S3 bucket to be new or empty; it can use any existing bucket. The error described ('output bucket already exists') is not typical for Athena.
MLS-C01 IAM Permissions for Athena Practice Question
This MLS-C01 practice question tests your understanding of data engineering. 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. A key principle to apply: iAM Permissions for Athena. 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.
Refer to the exhibit. A data engineer runs an Athena query and gets a failure. What is the most likely cause?
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 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
The IAM role used does not have permissions to write to S3.
The most likely cause for an Athena query failure is that the IAM role used does not have the necessary permissions to write query results to the specified S3 bucket. While syntax errors or encryption settings can cause issues, permissions are a frequent and common cause of failure in practice.
Key principle: IAM Permissions for Athena
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The query result location uses a bucket with default encryption enabled.
Why it's wrong here
Default encryption on the output bucket is not a common cause of failure; Athena can write to encrypted buckets as long as the role has appropriate decrypt permissions.
- ✗
The SQL query syntax is incorrect.
Why it's wrong here
Incorrect SQL syntax can cause a query failure, but it typically produces a syntax error message, and is less likely than a permissions issue in this general scenario.
- ✓
The IAM role used does not have permissions to write to S3.
Why this is correct
The IAM role used by Athena must have s3:PutObject permission for the output bucket. Lack of permissions is a frequent and common cause of query failures.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
IAM Permissions for Athena
- ✗
The output S3 bucket specified in the query result configuration already exists.
Why it's wrong here
Athena does not require the output S3 bucket to be new or empty; it can use any existing bucket. The error described ('output bucket already exists') is not typical for Athena.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Candidates often assume that the bucket must be new or empty, but Athena can use any existing bucket. The real trap is forgetting that the IAM role must have write permissions to the output bucket.
Trap categories for this question
Command / output trap
Default encryption on the output bucket is not a common cause of failure; Athena can write to encrypted buckets as long as the role has appropriate decrypt permissions.
Scenario analysis trap
Incorrect SQL syntax can cause a query failure, but it typically produces a syntax error message, and is less likely than a permissions issue in this general scenario.
Detailed technical explanation
How to think about this question
Athena uses the S3 bucket specified in the 'Query result location' setting to store query results as CSV or other formats. Under the hood, Athena creates a new folder (e.g., Unsaved/ or a timestamped folder) in that bucket; if the bucket itself already exists, Athena's validation logic rejects the request because it expects a new bucket to avoid accidental data overwrites or conflicts. This behavior is documented in the Athena API reference where the OutputLocation parameter must point to a bucket that does not yet exist.
KKey Concepts to Remember
- IAM Permissions for Athena
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
IAM Permissions for Athena
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 iAM Permissions for Athena, then practise related MLS-C01 questions on the same topic to reinforce the concept.
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FAQ
Questions learners often ask
What does this MLS-C01 question test?
Data Engineering — This question tests Data Engineering — IAM Permissions for Athena.
What is the correct answer to this question?
The correct answer is: The IAM role used does not have permissions to write to S3. — The most likely cause for an Athena query failure is that the IAM role used does not have the necessary permissions to write query results to the specified S3 bucket. While syntax errors or encryption settings can cause issues, permissions are a frequent and common cause of failure in practice.
What should I do if I get this MLS-C01 question wrong?
Review iAM Permissions for Athena, then practise related MLS-C01 questions on the same topic to reinforce the concept.
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?
IAM Permissions for Athena
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Last reviewed: Jul 4, 2026
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