How to Use Query Store Hints in SQL Server 2025 - NareshIT

 With the release of SQL Server 2025, Microsoft continues to refine performance tuning and query optimization capabilities. One of the most powerful features introduced is Query Store Hints, allowing database administrators to override query execution plans dynamically without modifying application code.

This article explores how Query Store Hints work, their benefits, real-world use cases, implementation steps, and best practices to enhance SQL Server performance.

What Are Query Store Hints in SQL Server 2025?

Query Store Hints is a feature that enables database administrators (DBAs) and developers to apply query-level hints through Query Store instead of modifying T-SQL code.

Why is this important?

🔹 Fine-tune query performance without changing application queries

🔹 Force specific execution plans to prevent performance regressions

🔹 Optimize queries dynamically without requiring code deployments

🔹 Improve workload performance in production without downtime

With Query Store Hints, businesses can achieve better query execution control while maintaining application stability.

Key Benefits of Query Store Hints

1️⃣ No Code Changes Required

✔ Apply hints at the database level without modifying stored procedures or application code.

2️⃣ Improved Query Performance

✔ Enforce optimized execution plans to improve query response time.

3️⃣ Faster Troubleshooting & Fixes

✔ Override inefficient plans caused by automatic query optimizations.

4️⃣ Enhanced Stability in Production

✔ Prevent performance regressions due to changing execution plans.

5️⃣ Better Plan Control for DBAs

✔ DBAs can force or modify execution plans without requiring developer intervention.

How Query Store Hints Work

🔹 Traditional Query Hints vs. Query Store Hints

In previous SQL Server versions, query hints were applied inside the T-SQL statement, requiring code modifications and deployments.

Example (traditional query hint approach):

SELECT * FROM Orders WITH (NOLOCK) WHERE OrderDate > '2024-01-01';

With Query Store Hints, the same optimization can be applied without modifying the original query.

How to Enable and Use Query Store Hints in SQL Server 2025

Step 1: Enable Query Store in Your Database

Before using Query Store Hints, ensure Query Store is enabled in SQL Server 2025:

ALTER DATABASE YourDatabase

SET QUERY_STORE = ON;

Step 2: Identify the Query ID

Find the Query ID from Query Store using:

SELECT query_id, query_sql_text  

FROM sys.query_store_query_text  

WHERE query_sql_text LIKE '%YourQueryPattern%';

Step 3: Apply Query Store Hint

Once the query_id is identified, apply a hint using:

EXEC sys.sp_query_store_set_hints  

    @query_id = 12345,  

    @hints = 'OPTION (RECOMPILE)';  

Step 4: Verify Query Store Hint Application

Check if the hint is active:

SELECT * FROM sys.query_store_hints WHERE query_id = 12345;

Step 5: Remove Query Store Hint (If Needed)

To remove the hint:

EXEC sys.sp_query_store_clear_hints @query_id = 12345;

Common Query Store Hints in SQL Server 2025

Use Cases for Query Store Hints

1. Fixing Parameter Sniffing Issues
Problem: SQL Server reuses execution plans based on parameter values, sometimes leading to suboptimal plans.
Solution: Use OPTIMIZE FOR UNKNOWN to prevent parameter sniffing issues.

EXEC sys.sp_query_store_set_hints
@query_id = 56789,
@hints = 'OPTION (OPTIMIZE FOR UNKNOWN)';

2. Forcing Index Usage Problem:

SQL Server chooses a full table scan instead of using an index. Solution: Apply the FORCESEEK hint to force an index seek.

EXEC sys.sp_query_store_set_hints 

@query_id = 67890, 

@hints = 'OPTION (FORCESEEK)';

3. Optimizing CPU Usage
Problem: Queries consuming too many CPU cores due to parallel execution.
Solution: Use MAXDOP 1 to limit the query to a single CPU core.

EXEC sys.sp_query_store_set_hints 

@query_id = 78901, 
@hints = 'OPTION (MAXDOP 1)';

Best Practices for Using Query Store Hints

✔ Use Query Store Hints as a Temporary Fix – They should not replace proper query tuning.
✔ Regularly Monitor Query Performance – Review query execution stats before applying hints.
✔ Avoid Overuse – Applying too many hints can override SQL Server’s optimizer intelligence.
✔ Use Indexing & Query Optimization First – Query Store Hints should be the last resort.
✔ Test Before Applying in Production – Always test hints in staging environments first.

Frequently Asked Questions (FAQs)

1. What is the difference between Query Hints and Query Store Hints? 

Query hints are applied inside the SQL query itself, requiring code modifications. Query Store Hints are applied externally, allowing hints to be added without changing T-SQL queries. 

2. Is Query Store Hints available in all SQL Server editions? 

No. Query Store Hints is available in SQL Server 2025 Enterprise and Standard Editions. 

  3. Can Query Store Hints be used in Azure SQL Database? 

Yes! Query Store Hints are supported in Azure SQL Database and Managed Instances. 

4. How do I know if Query Store Hints are improving performance? 

Use Query Store Reports in SQL Server Management Studio (SSMS) to compare execution plans before and after applying hints. 

  5. How can I remove a Query Store Hint if it causes issues? 

Run the following command to remove the hint:

EXEC sys.sp_query_store_clear_hints @query_id = 12345;

Conclusion: 

Query Store Hints in SQL Server 2025 offer unmatched flexibility in performance tuning without modifying application queries. By leveraging hints dynamically, DBAs can resolve performance bottlenecks, control execution plans, and improve query optimization in real-time.

Thank you for reading!

Stay updated with the latest posts at NIT Blogs . Click here to Read more!

Follow us: Facebook | Instagram | Twitter