DEA-C01 Data Store Management Practice Question
A company runs an Amazon RDS for PostgreSQL database. To meet disaster recovery requirements, they set up a cross-Region read replica. The replica has been lagging by several minutes. Which action is MOST effective to reduce the replica lag?
⚠ Common exam trap
Many candidates assume the primary database is the bottleneck and choose to scale it up, but the lag is caused by the replica's inability to apply changes quickly enough, making the replica's instance size the correct lever to adjust.
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
✓
Increase the instance size (memory and CPU) of the replica.
Increasing the instance size (memory and CPU) of the cross-Region read replica is the most effective action because replica lag in Amazon RDS for PostgreSQL is often caused by the replica being unable to keep up with the volume of write-ahead log (WAL) data arriving from the primary. A larger replica instance provides more compute and memory resources to apply WAL changes faster, reducing the replay lag. This directly addresses the bottleneck at the replica side without impacting the primary database.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable Multi-AZ on the primary database.
Why it's wrong here
Multi-AZ provides failover, not reduce replica lag.
- ✓
Increase the instance size (memory and CPU) of the replica.
Why this is correct
A larger replica can apply changes faster.
- ✗
Increase the instance size of the primary database.
Why it's wrong here
This helps write throughput but lag is about replica apply speed.
- ✗
Decrease the instance size of the replica to reduce cost.
Why it's wrong here
Smaller replica will lag more.
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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.