The SQL Query Store is a powerful feature in SQL Server that enables you to capture and analyze query performance data. It helps in identifying and troubleshooting performance issues by providing historical query statistics and execution plans. However, to ensure optimal performance and efficient use of resources, it’s important to follow best practices when managing and maintaining the SQL Query Store. In this article, we’ll explore some of these best practices.

Table of Contents

• Enable the SQL Query Store
• Set the Query Store Size
• Monitor Query Store Utilization
• Configuring Query Store Properties
• Regularly Purge Query Store Data
• Review Query Store Reports
• Conclusion

Enable the SQL Query Store

To start using the SQL Query Store, you need to enable it for your database. You can enable it at the database level using the following T-SQL command:

ALTER DATABASE [YourDatabaseName] SET QUERY_STORE = ON;

Enabling the query store will start capturing query performance data for the database.

Set the Query Store Size

By default, the SQL Query Store uses an automatic size management mode. However, setting a specific maximum size for the query store can help control the resources consumed. Consider setting a reasonable size based on the workload and available disk space using the following T-SQL command:

ALTER DATABASE [YourDatabaseName] SET QUERY_STORE (SIZE_BASED_CLEANUP_MODE = ON, MAX_SIZE = <your_desired_size>);

This will ensure the query store doesn’t consume excessive space on your disk.

Monitor Query Store Utilization

Regularly monitoring the query store utilization is crucial to ensure it’s not overloaded and impacting database performance. You can use the following T-SQL query to get an overview of query store utilization:

SELECT * FROM sys.database_query_store_options;

This query will provide information about the size of the query store, the current space used, and the cleanup policy.

Configuring Query Store Properties

The SQL Query Store provides several configuration options that you can adjust based on your specific needs. Some important properties to consider include:

• Data Flush Interval: Configure how often data gets flushed from the query store to disk using the T-SQL command:

  ALTER DATABASE [YourDatabaseName] SET QUERY_STORE (DATA_FLUSH_INTERVAL_SECONDS = <your_interval>);
  

• Query Capture Mode: Choose the appropriate query capture mode (ALL, AUTO, or NONE) based on your performance monitoring requirements.
• Statistics Collection: Determine how frequently query statistics are collected using the T-SQL command:

  ALTER DATABASE [YourDatabaseName] SET QUERY_STORE (QUERY_CAPTURE_MODE = <your_capture_mode>);
  

Adjusting these properties helps to optimize the performance and resource usage of the SQL Query Store.

Regularly Purge Query Store Data

Over time, the query store accumulates a significant amount of data. To prevent it from consuming excessive disk space, it’s important to purge outdated or unnecessary data. You can use the following T-SQL command to purge query store data:

ALTER DATABASE [YourDatabaseName] SET QUERY_STORE CLEAR ALL;

Regularly clearing out old data ensures that the query store remains manageable and continues to provide accurate performance insights.

Review Query Store Reports

The SQL Server Management Studio (SSMS) provides various built-in reports for analyzing the performance of queries stored in the query store. These reports include information on the top resource-consuming queries, query plans, and execution statistics. Regularly reviewing these reports assists in identifying performance bottlenecks and optimizing query performance.

Conclusion

The SQL Query Store is a powerful tool for managing and troubleshooting query performance issues in SQL Server. By following these best practices, you can ensure optimal usage, efficient resource utilization, and effective analysis of query performance data. Implementing these best practices will help you maintain a healthy and performant database environment. ‍ ‍ ‍ ‍ ‍#SQL #QueryStore