Using SQL Server Query Store for Advanced Query Tuning

SQL Server Query Store is a powerful feature that helps database administrators and developers analyze and optimize query performance. In this article, we'll explore advanced techniques for using SQL Server Query Store for query tuning, and we'll provide sample code to guide you through the process.

Enabling Query Store

To use Query Store, you need to enable it for your database. You can do this through SQL Server Management Studio or by using T-SQL. Here's an example of enabling Query Store via T-SQL:

ALTER DATABASE [YourDatabase]
SET QUERY_STORE = ON;
    

This command turns on Query Store for the specified database.

Collecting Query Data

Once Query Store is enabled, it starts collecting query performance data automatically. This data includes execution plans, query statistics, and wait statistics. You can access this data to identify poorly performing queries.

Identifying and Analyzing Query Regressions

Query Store provides a user-friendly interface to identify query regressions. You can track changes in query performance and easily spot problematic queries that used to perform well. You can use the following T-SQL code to identify queries with performance regressions:

SELECT *
FROM sys.query_store_runtime_stats
WHERE avg_duration > 10000; -- Adjust the threshold as needed
    

This code retrieves queries with an average duration greater than 10 seconds, indicating potential performance regressions.

Force Query Execution Plans

Query Store allows you to force a specific execution plan for a query, ensuring consistent performance. Here's an example of forcing a plan for a query:

EXEC sp_query_store_force_plan @query_id = 'YourQueryID';
    

This command forces a specific plan for a query identified by its ID.

Monitor and Review Execution Plans

Query Store provides detailed execution plans for queries. You can review these plans and identify areas for optimization. Use the "sys.query_store_plan" view to access execution plans for queries of interest.

SELECT * 
FROM sys.query_store_plan
WHERE query_id = 'YourQueryID';
    

This code retrieves the execution plans for a specific query.

Conclusion

SQL Server Query Store is a valuable tool for identifying, analyzing, and optimizing query performance. By following these advanced tips and techniques, you can efficiently tune your queries, ensuring optimal performance for your database applications.
Continue to explore Query Store features, stay updated with new releases, and practice with real-world query scenarios to master the art of query tuning.