DEA-C01 Data Operations and Support Practice Question
A data engineer is monitoring an Amazon Redshift cluster and notices that queries are taking longer than expected. The engineer checks the system tables and sees that many queries are waiting for 'WLM' resources. What is the most likely cause and recommended fix?
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 WLM queue concurrency is set too low; increase the concurrency level.
A wait for WLM (Workload Management) resources indicates that queries are being throttled due to insufficient concurrency slots. Increasing the WLM queue concurrency allows more queries to run simultaneously. Option A is incorrect because sort keys affect query scan efficiency, not WLM queue waits. Option B is incorrect because distribution style affects data redistribution, not concurrency throttling. Option D is incorrect because low disk space would cause different errors, not specifically WLM queue waits.
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 table sort keys are poorly designed; recreate tables with better sort keys.
Why it's wrong here
Sort keys affect scan performance, not concurrency.
- ✗
The distribution style is set to ALL; change to KEY distribution.
Why it's wrong here
Distribution affects data redistribution, not concurrency.
- ✓
The WLM queue concurrency is set too low; increase the concurrency level.
Why this is correct
Higher concurrency allows more simultaneous queries.
- ✗
The cluster is running low on disk space; resize the cluster.
Why it's wrong here
Disk space does not cause WLM wait.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.