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Question 996 of 1,786

Data Ingestion and Transformation →hardMultiple ChoiceObjective-mapped

Why AWS Glue Crawler Includes CSV Header as Data and How to Fix It

This DEA-C01 practice question tests your understanding of data ingestion and transformation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 CSV files into Amazon S3. Each file contains a header row. The pipeline uses AWS Glue to crawl the S3 bucket and create a table in the AWS Glue Data Catalog. However, the crawler is including the header as data. 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.

A
The S3 bucket has versioning enabled
Why wrong: Versioning does not affect header detection.
B
The crawler is configured to use a custom classifier that does not skip headers
Without a classifier that sets skip.header.line.count=1, headers are included.
C
The crawler is running in 'crawl all folders' mode
Why wrong: Mode does not remove headers.
D
The CSV files are not compressed
Why wrong: Compression does not affect header handling.

Full breakdown with real-world context →

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 crawler is configured to use a custom classifier that does not skip headers

The AWS Glue crawler uses built-in classifiers to infer schema of CSV files. The built-in CSV classifier automatically detects and skips header rows. However, if a custom classifier is configured and it does not have the correct setting to skip headers (e.g., `HasHeader` set to `false` or not defined), the crawler will treat the header row as data. Since the question describes the header being included as data, the most likely cause is that a custom classifier is in use that does not properly skip headers.

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.

✗
The S3 bucket has versioning enabled
Why it's wrong here
Versioning does not affect header detection.
✓
The crawler is configured to use a custom classifier that does not skip headers
Why this is correct
Without a classifier that sets skip.header.line.count=1, headers are included.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The crawler is running in 'crawl all folders' mode
Why it's wrong here
Mode does not remove headers.
✗
The CSV files are not compressed
Why it's wrong here
Compression does not affect header handling.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap is that candidates may focus on other aspects like S3 versioning or folder crawling, but the key is understanding that custom classifiers override the built-in behavior and must be configured correctly. The question does not explicitly state a custom classifier is in use, but option B identifies it as the likely cause, which requires knowledge that a misconfigured custom classifier can cause headers to be included.

Detailed technical explanation

How to think about this question

AWS Glue crawlers use a combination of built-in classifiers (e.g., CSV, JSON, Parquet) and optional custom classifiers to infer schema. The built-in CSV classifier automatically detects headers by checking if the first row contains distinct values that differ from the data type of subsequent rows. A custom classifier can override this behavior; if it is misconfigured (e.g., `HasHeader` set to `false` or a Grok pattern that does not exclude the header), the crawler will treat the first row as data. In real-world scenarios, this often happens when a custom classifier is created for non-standard CSV formats (e.g., with extra metadata lines) and the header-skipping logic is omitted.

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.

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

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 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.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this DEA-C01 question test?

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: The crawler is configured to use a custom classifier that does not skip headers — The AWS Glue crawler uses built-in classifiers to infer schema of CSV files. The built-in CSV classifier automatically detects and skips header rows. However, if a custom classifier is configured and it does not have the correct setting to skip headers (e.g., `HasHeader` set to `false` or not defined), the crawler will treat the header row as data. Since the question describes the header being included as data, the most likely cause is that a custom classifier is in use that does not properly skip headers.

What should I do if I get this DEA-C01 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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?

Read the scenario before looking for a memorised answer.

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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.