← MLS-C01·Amazon Web Services

Question 1,638 of 1,755

Data Engineering →mediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is that setting MaxConcurrentRuns to 3 is the most likely reason AWS Glue job bookmarks process all data instead of only new data. Job bookmarks rely on a consistent, unique state file to track which data has already been processed; when multiple concurrent runs are allowed, they can overwrite or corrupt this bookmark state, causing each run to lose its place and reprocess the entire dataset from scratch. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this question tests your understanding of how Glue job bookmarks depend on a single-threaded execution model for reliable incremental processing—a common trap is assuming bookmarks fail only due to missing primary keys or schema issues, when concurrency is the hidden culprit. Remember the memory tip: “One bookmark, one run—concurrency kills the checkpoint sun.”

MLS-C01 Data Engineering 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. 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.

Exhibit

Refer to the exhibit.

Resources:
  MyGlueJob:
    Type: AWS::Glue::Job
    Properties:
      Command:
        Name: glueetl
        ScriptLocation: s3://my-bucket/scripts/etl.py
      DefaultArguments:
        --TempDir: s3://my-bucket/temp/
        --job-bookmark-option: job-bookmark-enable
      MaxRetries: 0
      MaxConcurrentRuns: 3
      Role: arn:aws:iam::123456789012:role/GlueServiceRole

A company uses AWS Glue jobs with job bookmarks enabled to process incremental data. They notice that the job processes all data each time instead of only new data. What is the most likely reason?

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.

Question 1mediummultiple choice

Full question →

Exhibit

Refer to the exhibit.

Resources:
  MyGlueJob:
    Type: AWS::Glue::Job
    Properties:
      Command:
        Name: glueetl
        ScriptLocation: s3://my-bucket/scripts/etl.py
      DefaultArguments:
        --TempDir: s3://my-bucket/temp/
        --job-bookmark-option: job-bookmark-enable
      MaxRetries: 0
      MaxConcurrentRuns: 3
      Role: arn:aws:iam::123456789012:role/GlueServiceRole

A
The TempDir is not configured correctly.
Why wrong: TempDir is for temporary files, not bookmarks.
B
The job bookmark option is set to 'job-bookmark-enable' but should be 'job-bookmark-disable'.
Why wrong: Enabling is correct for incremental processing.
C
The source data does not have a column that can be used as a bookmark key.
Why wrong: While true, the more direct cause is concurrent runs.
D
The MaxConcurrentRuns is set to 3, which can cause bookmark conflicts.
Multiple concurrent runs can corrupt bookmark state.

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 MaxConcurrentRuns is set to 3, which can cause bookmark conflicts.

Job bookmarks require a unique identifier to track processed data. If the source data lacks a monotonically increasing column or the schema does not include a suitable key, bookmarks may not work. Setting MaxConcurrentRuns > 1 can cause issues with bookmarks. The correct answer: MaxConcurrentRuns is set to 3, which can interfere with bookmark state.

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 TempDir is not configured correctly.
Why it's wrong here
TempDir is for temporary files, not bookmarks.
✗
The job bookmark option is set to 'job-bookmark-enable' but should be 'job-bookmark-disable'.
Why it's wrong here
Enabling is correct for incremental processing.
✗
The source data does not have a column that can be used as a bookmark key.
Why it's wrong here
While true, the more direct cause is concurrent runs.
✓
The MaxConcurrentRuns is set to 3, which can cause bookmark conflicts.
Why this is correct
Multiple concurrent runs can corrupt bookmark state.
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.

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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.

What to study next

Got this wrong? Here's your next step.

Identify which MLS-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.

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FAQ

Questions learners often ask

What does this MLS-C01 question test?

Data Engineering — This question tests Data Engineering — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The MaxConcurrentRuns is set to 3, which can cause bookmark conflicts. — Job bookmarks require a unique identifier to track processed data. If the source data lacks a monotonically increasing column or the schema does not include a suitable key, bookmarks may not work. Setting MaxConcurrentRuns > 1 can cause issues with bookmarks. The correct answer: MaxConcurrentRuns is set to 3, which can interfere with bookmark state.

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

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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Last reviewed: Jun 20, 2026

Question Discussion

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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.