DEA-C01 Data Ingestion and Transformation Practice Question
A data engineer is designing a data ingestion pipeline to load clickstream data from an Amazon S3 bucket into an Amazon Redshift cluster. The data arrives in 5-minute batches. Which TWO actions should the engineer take to ensure data consistency and avoid duplicates? (Select TWO.)
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
✓
Use the STL_LOAD_ERRORS system table to monitor and resolve load errors.
Options C and E are correct. Using the STL_LOAD_ERRORS system table (option C) allows the engineer to monitor and resolve load errors, ensuring data consistency. Using a staging table with a MERGE operation (option E) helps avoid duplicates by performing an upsert. Option A (defining a SORTKEY) improves query performance but does not affect deduplication. Option B (disabling WLM) would reduce resource management and is not recommended. Option D (loading into a single slice) reduces performance and does not maintain order for consistency.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Define a SORTKEY on the target table to improve deduplication.
Why it's wrong here
SORTKEY improves query performance but does not prevent duplicates.
- ✗
Disable workload management (WLM) to maximize resources.
Why it's wrong here
Disabling WLM is not needed for consistency and may affect other queries.
- ✓
Use the STL_LOAD_ERRORS system table to monitor and resolve load errors.
Why this is correct
Monitoring load errors helps catch and fix issues that could cause duplicates or missing data.
- ✗
Load data into a single slice to maintain order.
Why it's wrong here
Loading into a single slice reduces parallelism and performance.
- ✓
Use a staging table and perform a MERGE operation to avoid duplicates.
Why this is correct
A staging table with MERGE (upsert) ensures that only new records are inserted, avoiding duplicates.
Visual reference
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 |
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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.