- A
Disable job bookmarking
Why wrong: Job bookmarking helps incremental processing, disabling it may reprocess all data.
- B
Increase the number of DPUs for the Glue job
More DPUs provide more parallelism and can speed up the job.
- C
Upgrade the RDS instance to a larger class
Why wrong: The bottleneck is likely the Glue job, not the source database.
- D
Use smaller file sizes in S3 output
Why wrong: Smaller files can increase metadata overhead and slow down processing.
Question 1,514 of 1,755
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.
A company is building a data pipeline using AWS Glue to transform data from Amazon RDS to Amazon S3. The pipeline runs daily and processes about 500 GB of data. The team notices that the job is taking longer than expected. Which change would MOST improve the job performance?
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
Increasing the number of DPUs (Data Processing Units) for the AWS Glue job directly allocates more distributed computing resources, allowing the job to process the 500 GB dataset in parallel across multiple workers. This is the most effective way to reduce runtime for a large-scale ETL job, as Glue's Spark-based execution scales horizontally with DPU count.
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.
- ✗
Disable job bookmarking
Why it's wrong here
Job bookmarking helps incremental processing, disabling it may reprocess all data.
- ✓
Increase the number of DPUs for the Glue job
Why this is correct
More DPUs provide more parallelism and can speed up the job.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Upgrade the RDS instance to a larger class
Why it's wrong here
The bottleneck is likely the Glue job, not the source database.
- ✗
Use smaller file sizes in S3 output
Why it's wrong here
Smaller files can increase metadata overhead and slow down processing.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse increasing DPUs with simply adding more memory, when in fact it scales both CPU and memory, and they may incorrectly assume that optimizing output file sizes or disabling bookmarks is a performance fix, whereas those changes address different concerns like cost or incremental processing.
Detailed technical explanation
How to think about this question
AWS Glue runs on Apache Spark, where DPUs represent a unit of processing power (4 vCPU + 16 GB memory). Increasing DPUs from the default 10 to a higher value (e.g., 50) allows more Spark executors to process partitions concurrently, directly reducing wall-clock time for shuffle-heavy transformations. However, there is a diminishing return beyond a certain point due to driver overhead and data skew, so monitoring Spark UI metrics is essential for optimal tuning.
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
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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 — Increasing the number of DPUs (Data Processing Units) for the AWS Glue job directly allocates more distributed computing resources, allowing the job to process the 500 GB dataset in parallel across multiple workers. This is the most effective way to reduce runtime for a large-scale ETL job, as Glue's Spark-based execution scales horizontally with DPU count.
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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Last reviewed: Jul 4, 2026
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