DEA-C01 Data Ingestion and Transformation Practice Question
A company uses AWS DMS to migrate data from an on-premises Oracle database to Amazon RDS for PostgreSQL. The migration is ongoing with continuous replication. The data engineer notices that some changes are not being captured in the target database. What is the MOST likely cause?
⚠ Common exam trap
Watch out — candidates often assume missing changes are due to network or configuration errors (like VPC or table mapping), but the real issue is the source database's log retention policy, which is a subtle but critical requirement for CDC with DMS.
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 source Oracle database is not configured to retain archived redo logs for a sufficient period.
In AWS DMS continuous replication (CDC), the service reads changes from the source Oracle database's archived redo logs. If the logs are rotated or deleted before DMS has a chance to process them, changes are lost. Option D is correct because insufficient retention of archived redo logs is the most likely cause of missing changes in the target.
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 VPC peering connection between on-premises and AWS is down.
Why it's wrong here
Would cause connectivity error, not missing changes.
- ✗
The DMS task's table mapping is incorrectly configured.
Why it's wrong here
Would cause specific tables to be missing, not changes.
- ✗
DMS is not publishing task logs to CloudWatch Logs.
Why it's wrong here
CloudWatch logging is for monitoring, not capturing changes.
- ✓
The source Oracle database is not configured to retain archived redo logs for a sufficient period.
Why this is correct
DMS requires archived logs to capture changes; if logs are purged, changes are lost.
Go deeper
Related to this question
About these practice questions
This DEA-C01 question is part of Courseiva's 1,711-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.