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Question 337 of 1,755

Data Engineering →hardMultiple ChoiceObjective-mapped

MLS-C01 Data Engineering Practice Question

This MLS-C01 practice question tests your understanding of data engineering. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 uses AWS Glue to run ETL jobs on a daily schedule. The jobs are failing intermittently with 'OutOfMemory' errors. The data volume has grown 5x over the past month. Which is the MOST cost-effective fix?

A
Increase the number of partitions in the source S3 data
Why wrong: Partitioning helps with performance, not memory errors.
B
Increase the number of DPUs for the Glue job
More DPUs provide more memory and parallelism.
C
Reduce the data volume by sampling
Why wrong: Reducing data may impact accuracy and is not a proper solution.
D
Switch from AWS Glue to Amazon EMR
Why wrong: EMR is more expensive and requires management.

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

✓

Increase the number of DPUs for the Glue job

The 'OutOfMemory' errors in AWS Glue are caused by insufficient compute resources (DPUs) to process the 5x increased data volume. Increasing the number of DPUs allocates more memory and processing capacity to the job, directly addressing the memory shortage without changing the data or architecture. This is the most cost-effective fix because it scales resources incrementally rather than switching to a more expensive service like EMR.

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.

✗
Increase the number of partitions in the source S3 data
Why it's wrong here
Partitioning helps with performance, not memory errors.
✓
Increase the number of DPUs for the Glue job
Why this is correct
More DPUs provide more memory and parallelism.
Related concept
Read the scenario before looking for a memorised answer.
✗
Reduce the data volume by sampling
Why it's wrong here
Reducing data may impact accuracy and is not a proper solution.
✗
Switch from AWS Glue to Amazon EMR
Why it's wrong here
EMR is more expensive and requires management.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may assume the issue is data partitioning (Option A) or that a more powerful service like EMR (Option D) is always better, when in fact the simplest and most cost-effective solution is to adjust the Glue job's DPU allocation to match the increased workload.

Detailed technical explanation

How to think about this question

AWS Glue allocates a default of 10 DPUs per job, with each DPU providing 4 vCPU and 16 GB of memory. When data volume grows, the memory per partition can exceed the available heap, causing OutOfMemory errors. Increasing DPUs scales the number of executors, allowing more partitions to be processed concurrently and reducing memory pressure per executor. The Glue job's 'MaxCapacity' or 'NumberOfWorkers' parameter directly controls this, and for memory-intensive transformations (e.g., joins, aggregations), the G.1X or G.2X worker types can be used to provide more memory per DPU.

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 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 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 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: Increase the number of DPUs for the Glue job — The 'OutOfMemory' errors in AWS Glue are caused by insufficient compute resources (DPUs) to process the 5x increased data volume. Increasing the number of DPUs allocates more memory and processing capacity to the job, directly addressing the memory shortage without changing the data or architecture. This is the most cost-effective fix because it scales resources incrementally rather than switching to a more expensive service like EMR.

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

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

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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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.