MLS-C01 Data Engineering Practice Question
Which TWO data formats are columnar and optimized for analytics queries in Amazon S3?
⚠ Common exam trap
Watch out — candidates often confuse 'binary format' (Avro) or 'structured text' (JSON, CSV) with columnar optimization, failing to recognize that only columnar formats like ORC and Parquet provide the compression and predicate pushdown needed for analytics at scale.
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
✓
ORC
ORC (Optimized Row Columnar) is a columnar storage format that stores data in a column-oriented manner, enabling efficient compression and predicate pushdown for analytics queries on Amazon S3. It is designed for high-performance read operations in big data frameworks like Apache Hive and Spark, making it ideal for aggregation and filtering workloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
CSV
Why it's wrong here
CSV is row-oriented.
- ✓
ORC
Why this is correct
ORC is columnar and optimized for analytics.
- ✗
JSON
Why it's wrong here
JSON is a text format, not columnar.
- ✗
Avro
Why it's wrong here
Avro is row-oriented.
- ✓
Parquet
Why this is correct
Parquet is columnar and optimized for analytics.
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
Related to this question
About these practice questions
Courseiva writes every MLS-C01 question from scratch — 1,672 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
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.