The answer is to configure Limited LOB mode with a specified max LOB size in the task settings. This is correct because when AWS DMS replicates large BLOB columns, the default full LOB mode attempts to load the entire BLOB into memory for each row, which quickly exhausts the DMS instance’s memory when handling millions of rows with massive BLOBs. By switching to Limited LOB mode, DMS truncates each BLOB to a defined maximum size, drastically reducing per-row memory consumption and preventing OutOfMemory errors. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of DMS task tuning for high-volume, large-object replication, where a common trap is to increase the instance size instead of adjusting LOB handling. A useful memory tip is “Limit the LOB to save the job”—remember that limiting LOB size is often more effective than scaling the instance.
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. 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 Amazon RDS for MySQL as a source for AWS DMS to replicate data to S3. The replication task is failing with 'OutOfMemory' errors on the DMS instance. The source table has 10 million rows with large BLOB columns. Which THREE changes would most likely resolve the issue?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set the LOB column settings to 'Limited LOB mode' and specify a max LOB size.
Option A is correct because setting LOB columns to 'Limited LOB mode' with a specified max LOB size prevents DMS from loading entire LOBs into memory. Instead, DMS truncates LOBs to the specified size, reducing memory consumption and avoiding OutOfMemory errors when replicating large BLOB columns from MySQL to S3.
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.
✓
Set the LOB column settings to 'Limited LOB mode' and specify a max LOB size.
Why this is correct
Limited LOB mode avoids loading entire LOBs into memory.
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.
✗
Disable logging for the DMS task to free memory.
Why it's wrong here
Logging uses minimal memory; disabling it does not resolve OOM.
✗
Enable Full LOB mode to handle LOBs more efficiently.
Why it's wrong here
Full LOB mode loads entire LOBs into memory, worsening the issue.
✓
Increase the DMS replication instance size to a compute-optimized class.
Why this is correct
More memory prevents OOM errors.
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.
✓
Increase the number of parallel threads in the task settings.
Why this is correct
More threads can process smaller batches, reducing per-thread memory usage.
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
The trap here is that candidates often assume Full LOB mode is always the safest choice for large objects, but it actually increases memory usage and can cause OutOfMemory errors, whereas Limited LOB mode with a max size is the correct memory-saving approach.
Detailed technical explanation
How to think about this question
In DMS, Full LOB mode reads the entire LOB value into memory before writing to the target, which can cause memory exhaustion with large BLOBs. Limited LOB mode truncates LOBs to a user-defined maximum size (e.g., 64 KB), reducing memory footprint. Increasing instance size (Option D) provides more memory, while increasing parallel threads (Option E) can improve throughput but may also increase memory pressure if not balanced with LOB settings.
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.
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.
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: Set the LOB column settings to 'Limited LOB mode' and specify a max LOB size. — Option A is correct because setting LOB columns to 'Limited LOB mode' with a specified max LOB size prevents DMS from loading entire LOBs into memory. Instead, DMS truncates LOBs to the specified size, reducing memory consumption and avoiding OutOfMemory errors when replicating large BLOB columns from MySQL to S3.
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.
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.