Quick Answer
The answer is that the provisioned read capacity is too low. This is the most likely cause of the DynamoDB slow query because the reporting job queries by the partition key 'pk' and filters on the sort key 'sk' using a range condition, which is an efficient read pattern; however, the table has only 5 read capacity units (RCU), which is insufficient for the volume of data being scanned and returned by the reporting job. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your ability to distinguish between throttling due to capacity limits and performance issues caused by inefficient query design or missing indexes—a common trap is to blame the range filter or lack of a secondary index when the real culprit is simply starving the table of read throughput. Remember the memory tip: "RCU is the fuel, not the filter"—if your query pattern is already efficient, always check the capacity gauge first.
This DEA-C01 practice question tests your understanding of data store management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
The exhibit shows the output of describe-table for a DynamoDB table. The table is used for a reporting job that queries by 'pk' and filters on 'sk' using a range condition. The job is running slowly. 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.
The table lacks a global secondary index (GSI).
Why wrong: Query on pk and sk range does not require GSI.
The provisioned read capacity is too low.
5 RCU is very low for reporting queries.
The table uses provisioned throughput instead of on-demand.
Why wrong: Provisioned is fine; the issue is the low number.
The table needs a local secondary index (LSI) on 'sk'.
Why wrong: sk is already a range key; LSI not needed.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The provisioned read capacity is too low.
The table has only 5 read capacity units, which is likely too low for the reporting job. Auto scaling or increasing RCU would help. Indexes and LSI are not shown to be causing slowness.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The table lacks a global secondary index (GSI).
Why it's wrong here
Query on pk and sk range does not require GSI.
The provisioned read capacity is too low.
Why this is correct
5 RCU is very low for reporting queries.
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 table uses provisioned throughput instead of on-demand.
Why it's wrong here
Provisioned is fine; the issue is the low number.
The table needs a local secondary index (LSI) on 'sk'.
Why it's wrong here
sk is already a range key; LSI not needed.
Common exam traps
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
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
Identify which DEA-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
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
The correct answer is: The provisioned read capacity is too low. — The table has only 5 read capacity units, which is likely too low for the reporting job. Auto scaling or increasing RCU would help. Indexes and LSI are not shown to be causing slowness.
Identify which DEA-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.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
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.
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