The answer is Parquet, ORC, and Avro. These three file formats are the best compression formats for Apache Spark on AWS because they are splittable, support native compression codecs like Snappy, Gzip, and Zstandard, and are designed for efficient columnar or row-based processing in distributed systems. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding of storage optimization trade-offs—Parquet and ORC excel in analytics due to columnar pruning and predicate pushdown, while Avro is preferred for row-oriented streaming or schema evolution. A common trap is choosing JSON or CSV, which technically support compression but lack the performance characteristics Spark requires for large-scale ETL on Amazon EMR or AWS Glue. Remember the mnemonic “POA” (Parquet, ORC, Avro) to quickly recall the three formats that combine compression with Spark’s parallel processing capabilities.
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. 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 is ingesting data from multiple sources into Amazon S3 using AWS Glue. The data is then transformed using Apache Spark on Amazon EMR. The data engineer wants to reduce the cost of storing and processing data by compressing the ingested files. Which THREE file formats support compression and are commonly used with Spark? (Choose THREE.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
ORC
Correct options: A, C, and D. Parquet, ORC, and Avro all support compression and are commonly used with Spark. Option B is wrong because JSON can be compressed but is not a columnar format and is less efficient; however, it does support compression, but the question asks for formats commonly used with Spark for analytics; Parquet, ORC, and Avro are typical. Option E is wrong because CSV can be compressed but is not efficient for Spark processing. The answer is A, C, D.
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.
✓
ORC
Why this is correct
ORC is a columnar format that supports compression and is optimized for Hive/Spark.
Related concept
Read the scenario before looking for a memorised answer.
✓
Parquet
Why this is correct
Parquet is a columnar format that supports compression and is widely used with Spark.
Related concept
Read the scenario before looking for a memorised answer.
✗
JSON
Why it's wrong here
JSON can be compressed but is not a columnar format and is less efficient for analytics.
✗
CSV
Why it's wrong here
CSV can be compressed but is not efficient for Spark processing.
✓
Avro
Why this is correct
Avro is a row-based format that supports compression and is used with Spark.
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 Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: ORC — Correct options: A, C, and D. Parquet, ORC, and Avro all support compression and are commonly used with Spark. Option B is wrong because JSON can be compressed but is not a columnar format and is less efficient; however, it does support compression, but the question asks for formats commonly used with Spark for analytics; Parquet, ORC, and Avro are typical. Option E is wrong because CSV can be compressed but is not efficient for Spark processing. The answer is A, C, D.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.