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Data Operations and Support →easyMultiple ChoiceObjective-mapped

DEA-C01 Data Operations and Support Practice Question

This DEA-C01 practice question tests your understanding of data operations and support. 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 data engineer is troubleshooting an Amazon Redshift cluster that is running slowly. The cluster has 4 dc2.large nodes. The engineer runs a query that scans a large table and notices that the query uses only a single slice instead of all slices. The table is distributed with DISTSTYLE ALL. What is the most likely reason for the query using only one slice?

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.

A
The query is running on the leader node instead of the compute nodes.
Why wrong: The leader node distributes queries to compute nodes; the query is running on compute nodes but only one slice per node.
B
The table uses DISTSTYLE ALL, which stores the entire table on a single slice per node.
DISTSTYLE ALL replicates the table to each node, but it is stored on one slice per node, limiting parallelism.
C
The workload management (WLM) queue is configured with a single query slot.
Why wrong: WLM queue slots affect concurrent query execution, not slice utilization for a single query.
D
The table does not have a sort key defined.
Why wrong: Missing sort key affects performance but does not cause single-slice usage.

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 table uses DISTSTYLE ALL, which stores the entire table on a single slice per node.

Option B is correct because DISTSTYLE ALL replicates the entire table to every node, but within each node, the data is stored on a single slice. For dc2.large nodes, which have 2 slices per node, this means that a full table scan will only use one slice per node, not all available slices. This leads to underutilization and slow query performance. Option A is incorrect because the leader node does not execute data queries; it only coordinates them. Queries are executed on compute nodes. Option C is incorrect because WLM queue slots control concurrency, not the number of slices used by a single query. Option D is incorrect because sort keys affect data ordering and compression, not slice distribution.

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 query is running on the leader node instead of the compute nodes.
Why it's wrong here
The leader node distributes queries to compute nodes; the query is running on compute nodes but only one slice per node.
✓
The table uses DISTSTYLE ALL, which stores the entire table on a single slice per node.
Why this is correct
DISTSTYLE ALL replicates the table to each node, but it is stored on one slice per node, limiting parallelism.
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 workload management (WLM) queue is configured with a single query slot.
Why it's wrong here
WLM queue slots affect concurrent query execution, not slice utilization for a single query.
✗
The table does not have a sort key defined.
Why it's wrong here
Missing sort key affects performance but does not cause single-slice usage.

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

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

What to study next

Got this wrong? Here's your next step.

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

Questions learners often ask

What does this DEA-C01 question test?

Data Operations and Support — This question tests Data Operations and Support — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The table uses DISTSTYLE ALL, which stores the entire table on a single slice per node. — Option B is correct because DISTSTYLE ALL replicates the entire table to every node, but within each node, the data is stored on a single slice. For dc2.large nodes, which have 2 slices per node, this means that a full table scan will only use one slice per node, not all available slices. This leads to underutilization and slow query performance. Option A is incorrect because the leader node does not execute data queries; it only coordinates them. Queries are executed on compute nodes. Option C is incorrect because WLM queue slots control concurrency, not the number of slices used by a single query. Option D is incorrect because sort keys affect data ordering and compression, not slice distribution.

What should I do if I get this DEA-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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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.