DP-300 Practice Question: Monitor, configure, and optimize database resources
You manage an Azure SQL Database that is part of an Always On availability group in Azure SQL Managed Instance. You notice that the secondary replica is experiencing high log send queue size. The primary replica has ample CPU and I/O resources. The network latency between replicas is low. What is the most likely cause of the high log send queue?
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 secondary replica's log apply rate is slower than the log generation rate on the primary.
The most likely cause of high log send queue is that the secondary replica's log apply rate is slower than the log generation rate on the primary (Option C). This typically occurs when the secondary replica is under-provisioned or has high I/O contention, causing it to fall behind in applying received log records. Option A (asynchronous commit) is incorrect because asynchronous commit can actually reduce log send queue pressure by not waiting for the secondary, but it does not directly cause queue buildup. Option B (log flush delays on primary) is unlikely because the primary has ample CPU and I/O resources. Option D (insufficient network bandwidth) is unlikely given that network latency is low and the primary resources are ample.
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 secondary replica is configured with asynchronous commit.
Why it's wrong here
Asynchronous commit would not cause log send queue; it would cause data loss risk.
- ✗
The primary replica is experiencing log flush delays.
Why it's wrong here
If primary were slow, log generation would be slow, not queue buildup.
- ✓
The secondary replica's log apply rate is slower than the log generation rate on the primary.
Why this is correct
A slow secondary can cause backlog, even with fast network.
- ✗
The network bandwidth between replicas is insufficient.
Why it's wrong here
Network latency is low, and bandwidth is not specified but unlikely if latency is low.
Go deeper
Related to this question
Learn chapter
Overview of Azure Data Platform Options
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
Key term
Azure SQL Managed Instance
Azure SQL Managed Instance is a fully managed cloud database service that gives you nearly all the features of Microsoft SQL Server on your own server, without you having to manage the hardware or operating system.
About these practice questions
Courseiva writes every DP-300 question from scratch — 906 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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 DP-300 practice question is part of Courseiva's free Microsoft 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 DP-300 exam.