DP-300 Practice Question: Monitor, configure, and optimize database resources
You are monitoring an Azure SQL Database using Query Performance Insight and notice that a specific query has a high average duration and high CPU usage. The query plan shows a clustered index scan on a large table. Which two actions should you take to optimize performance? (Choose two.)
⚠ Common exam trap
The trap here is that candidates often jump to index rebuilds or scaling up resources, overlooking that stale statistics are a frequent and easily fixable cause of poor query plans in Azure SQL Database.
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
✓
Update statistics on the table to ensure the optimizer has current information.
Updating statistics provides the query optimizer with current data distribution information, which can lead to a more efficient query plan, potentially avoiding the clustered index scan. In Azure SQL Database, stale statistics are a common cause of suboptimal plans, and updating them is a low-cost, non-disruptive first step before considering index changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Rebuild the clustered index to reduce fragmentation.
Why it's wrong here
Fragmentation is not the primary issue; a scan is due to missing indexes.
- ✓
Update statistics on the table to ensure the optimizer has current information.
Why this is correct
Up-to-date statistics help the optimizer choose efficient plans.
- ✗
Force a different query plan using Query Store hints.
Why it's wrong here
Forcing a plan without analysis can cause performance regression.
- ✗
Increase the DTU service tier of the database.
Why it's wrong here
DTU model is not applicable to vCore-based Azure SQL Database.
- ✓
Create a covering nonclustered index on the columns used in the query.
Why this is correct
A covering index can replace the scan with a seek.
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 Indexes
Structures in Azure SQL Database that speed up data retrieval by providing quick access paths to rows, similar to a book index.
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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.