DP-300 Practice Question: Monitor, configure, and optimize database resources
You have an Azure SQL Managed Instance used for an e-commerce platform. During a flash sale, you experience a deadlock that causes transaction rollbacks. You need to minimize deadlock occurrences in the future. What should you implement?
⚠ Common exam trap
DP-300 often tests the misconception that monitoring tools (deadlock graphs, Extended Events) or more resources (vCores) prevent deadlocks, when only isolation-level or access-pattern changes actually reduce them.
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
✓
Enable READ COMMITTED SNAPSHOT isolation level.
Enabling READ COMMITTED SNAPSHOT isolation (RCSI) makes readers use row versioning from tempdb instead of taking shared locks, which eliminates the classic reader-writer deadlock pattern that plagues e-commerce workloads mixing SELECTs and UPDATEs. This directly reduces deadlock frequency without changing application code.
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 READ COMMITTED SNAPSHOT isolation level.
Why this is correct
READ COMMITTED SNAPSHOT uses row versioning in tempdb, so readers don't take shared locks on data pages. This removes the shared-versus-exclusive lock conflicts that cause deadlocks during concurrent flash-sale transactions, satisfying the requirement to minimise deadlock occurrences.
- ✗
Configure deadlock graph in Extended Events.
Why it's wrong here
Extended Events deadlock graphs only capture and diagnose deadlock events after they occur; they neither prevent nor reduce future occurrences. Capturing graphs is tempting because it is the standard first step in deadlock investigation, and it would be the correct choice when you need to identify the specific resources and statements involved before designing a fix.
- ✗
Enable automatic tuning to force last good plan.
Why it's wrong here
Automatic tuning's force-last-good-plan corrects plan regressions, not the lock ordering and transaction interleaving that produce deadlocks under concurrent writes. It is tempting because it genuinely resolves parameter-sniffing and plan-choice performance faults, which is the right fix when a query suddenly slows after a plan change rather than when transactions block each other.
- ✗
Increase the instance vCores to improve concurrency.
Why it's wrong here
Adding vCores increases compute capacity but does not alter the access patterns or lock ordering that cause deadlocks; more parallelism can even increase contention. Scaling up is tempting because it relieves CPU and throughput bottlenecks during flash sales, and it would be correct if the symptom were slow queries or resource saturation rather than cyclic blocking.
Go deeper
Related to this question
Learn chapter
Deploying and Configuring Azure SQL Managed Instance
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
This DP-300 question is part of Courseiva's 574-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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
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.