DBS-C01 Management and Operations Practice Question
A company runs an Amazon RDS for MySQL DB instance with Multi-AZ. The application team reports that a recent schema change caused a significant increase in replication lag. The instance has a read replica in a different AWS Region. Which THREE actions should be taken to reduce replication lag?
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
✓
Identify and optimize any long-running transactions or DDL statements that may be blocking replication.
Options A, C, and D are correct actions to reduce replication lag. A: Optimizing long-running transactions or DDL statements helps prevent blocking on the primary that can cause lag. C: Monitoring the ReplicaLag metric in CloudWatch allows you to identify trends and set alarms for proactive management. D: Setting the transaction isolation level to READ COMMITTED reduces locking on the primary, which can decrease replication lag. Option B is not the best action: increasing the instance class may improve performance but does not directly address the root cause of lag from schema changes. Option E is incorrect because disabling binary logging would stop replication entirely, not reduce lag.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Identify and optimize any long-running transactions or DDL statements that may be blocking replication.
Why this is correct
Long-running transactions can cause replication lag by holding locks or delaying binary log events.
- ✗
Increase the DB instance class for both the primary and read replica to improve performance.
Why it's wrong here
While increasing instance class might help, it is not always necessary and may not address the root cause.
- ✓
Monitor the ReplicaLag metric in Amazon CloudWatch to understand the trend and set alarms.
Why this is correct
Monitoring lag helps in diagnosing the issue and taking corrective actions.
- ✓
Set the transaction isolation level to READ COMMITTED to reduce locking.
Why this is correct
READ COMMITTED reduces locking compared to REPEATABLE READ, which can help reduce replication lag.
- ✗
Disable binary logging on the primary instance to reduce I/O overhead.
Why it's wrong here
Disabling binlog stops replication entirely, which is not a valid solution.
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Written by Johnson Ajibi, MSc IT Security
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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.