DEA-C01 Data Store Management Practice Question
A data engineer is responsible for a data warehouse on Amazon Redshift that stores 5 TB of data. The engineer needs to load 50 GB of new data daily from Amazon S3 into Redshift. The current load process uses the COPY command and takes 2 hours, which is within the maintenance window. However, the engineer wants to optimize the load time and reduce the impact on concurrent queries. The engineer notices that the tables are not distributed evenly across the slices. The cluster has 4 nodes of dc2.large. Which approach will best improve load performance?
⚠ Common exam trap
Watch out — candidates often assume adding more nodes (scaling out) always improves load performance, but the real bottleneck is slice-level data skew, which EVEN distribution directly fixes without additional cost.
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
✓
Change the distribution style of the tables to EVEN.
The COPY command distributes data across slices based on the table's distribution style. With dc2.large nodes, each node has 2 slices, so a 4-node cluster has 8 slices. If tables are not distributed evenly, some slices handle more data, causing bottlenecks. Changing the distribution style to EVEN forces rows to be spread uniformly across all slices, maximizing parallelism during the COPY load and reducing load time.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the cluster size to 8 nodes.
Why it's wrong here
Scaling up may improve performance but is costly and not the root cause.
- ✓
Change the distribution style of the tables to EVEN.
Why this is correct
EVEN distribution ensures each slice gets an equal amount of data, improving parallelism.
- ✗
Use GZIP compression on the S3 files.
Why it's wrong here
Compression reduces transfer time but doesn't solve uneven distribution.
- ✗
Add sort keys to the tables based on the load timestamp.
Why it's wrong here
Sort keys improve query performance, not load performance.
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 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.