MLS-C01 Data Engineering Practice Question
A company is using Amazon S3 as a data lake. The data engineering team needs to catalog the schema of the data and make it available for querying with Amazon Athena. Which AWS Glue component should be used?
⚠ Common exam trap
Candidates often confuse Glue Crawlers (schema discovery) with Glue ETL jobs (data transformation) or Glue DataBrew (data preparation), assuming any Glue component can catalog data, but only Crawlers perform automatic schema inference and metadata population.
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
✓
AWS Glue Crawlers
AWS Glue Crawlers automatically scan data in Amazon S3, infer the schema, and populate the AWS Glue Data Catalog with metadata tables. This makes the data immediately available for querying with Amazon Athena without manual schema definition.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
AWS Glue Studio
Why it's wrong here
Glue Studio is a visual editor for ETL jobs.
- ✓
AWS Glue Crawlers
Why this is correct
Crawlers populate the Glue Data Catalog with table definitions.
- ✗
AWS Glue ETL jobs
Why it's wrong here
ETL jobs transform data, not catalog schemas.
- ✗
AWS Glue DataBrew
Why it's wrong here
DataBrew is for data cleaning and preparation, not cataloging.
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 |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MLS-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 MLS-C01 exam.