DBS-C01 Deployment and Migration Practice Question
A company is migrating a PostgreSQL database to Amazon Aurora PostgreSQL. They have set up AWS DMS with change data capture (CDC). However, after the initial load, the CDC replication is experiencing high latency. What is the MOST likely cause?
⚠ Common exam trap
A common mix-up: candidates assume network or infrastructure issues (like bandwidth or storage) are the primary cause of CDC latency, overlooking the fundamental constraint that DMS must wait for transaction commits before applying changes.
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 database has large transactions that are not committed quickly.
Large uncommitted transactions on the source database cause DMS CDC to buffer changes until the transaction commits, leading to high latency. DMS must wait for the commit record before applying changes to the target Aurora instance, and during this time, CDC replication stalls, accumulating a backlog of changes.
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 target Aurora instance has insufficient storage.
Why it's wrong here
Storage issues cause errors, not latency.
- ✗
The DMS instance is using an older engine version.
Why it's wrong here
Version is unlikely cause.
- ✓
The source database has large transactions that are not committed quickly.
Why this is correct
Large uncommitted transactions delay CDC.
- ✗
The network bandwidth is too low.
Why it's wrong here
Network affects all phases equally.
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JA
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.