DP-300 Practice Question: Monitor, configure, and optimize database resources
You manage an Azure SQL Database that has automatic tuning enabled. You receive an alert that the database is experiencing plan regression. The automatic tuning has forced a plan, but performance is still poor. What should you do first?
⚠ Common exam trap
DP-300 often tests the order of operations — candidates want to immediately fix the problem (revert plan, scale up) but the correct first step is always to diagnose using Query Store.
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
✓
Review the Query Store to identify the root cause of regression.
When automatic tuning has forced a plan but performance remains poor, the first step is to investigate the root cause using Query Store, which captures query plans, runtime statistics, and regressions. Query Store provides the historical data needed to understand why the forced plan is not optimal and whether the regression is due to parameter sniffing, statistics, or schema changes. Only after diagnosis should you consider reverting or disabling automatic tuning.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disable automatic tuning and create a plan guide.
Why it's wrong here
Disabling automatic tuning removes the mechanism that detected and forced the plan, so the regression persists unmanaged; the first step is to verify the forced plan and revert it via automatic tuning's plan history. Plan guides suit third-party or legacy queries where automatic tuning cannot intervene.
- ✓
Review the Query Store to identify the root cause of regression.
Why this is correct
Query Store captures every plan, runtime statistic and regression event, so it reveals why the forced plan still performs poorly before you change any tuning configuration. Automatic tuning only forces a plan; diagnosing the underlying cause requires the historical execution data Query Store retains.
- ✗
Manually revert to the previous plan using Query Store.
Why it's wrong here
Manually reverting to a previous plan without first understanding why the forced plan is performing poorly could lead to repeated regression. The first step should be to review the Query Store to identify the root cause.
- ✗
Scale up the database to reduce resource pressure.
Why it's wrong here
Scaling up adds CPU and memory but leaves the regressed forced plan executing the same inefficient shape, so the underlying plan regression remains. Scaling addresses genuine resource saturation, not plan choice; here the forced plan itself is the fault.
Go deeper
Related to this question
Learn chapter
Optimizing Database Query and Index Performance
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
Query Store
Query Store is a built-in SQL Server feature that captures and stores a history of query execution plans and performance data for easy monitoring and troubleshooting.
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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.