DBS-C01 Management and Operations Practice Question
A company has an Amazon Redshift cluster that is running slowly on complex queries. The cluster has 10 dc2.large nodes. The 'QueryDuration' metric shows high values for several queries. The team wants to improve performance without changing queries. Which action is MOST likely to help?
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
✓
Add more nodes of the same type to the cluster.
Adding more nodes (scaling out) increases the cluster's compute capacity, allowing complex queries to process data in parallel without any query changes. Option C is incorrect because Redshift Spectrum requires data to be in S3 and external tables to be defined, which would require modifying queries to reference those tables. Option B reduces storage I/O but not CPU-bound complex queries. Option D increasing concurrency can cause resource contention, slowing queries.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add more nodes of the same type to the cluster.
Why this is correct
Adding more nodes increases the cluster's compute capacity, allowing complex queries to process more data in parallel without any changes to the queries themselves.
- ✗
Enable compression on all columns.
Why it's wrong here
Enabling compression reduces storage and I/O but does not directly improve the performance of complex queries that involve CPU-intensive operations.
- ✗
Enable Redshift Spectrum to offload queries to Amazon S3.
Why it's wrong here
Redshift Spectrum allows querying data in S3, but it requires defining external tables and modifying queries to reference those tables, contradicting the requirement to not change queries.
- ✗
Increase the workload management (WLM) concurrency level.
Why it's wrong here
Increasing WLM concurrency may lead to resource contention among concurrent queries, potentially degrading performance rather than improving it.
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 |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.