Configure Query Store

Query Store is a powerful feature in Azure SQL Database that allows you to monitor and manage the performance of your database queries. It helps you identify and troubleshoot performance issues, and provides valuable insights into query execution plans and resource usage. This article will guide you through the process of configuring Query Store in Azure SQL Database.

Enabling Query Store

To enable Query Store for your Azure SQL Database, you can use the following T-SQL statement:

ALTER DATABASE [database_name] SET QUERY_STORE = ON;

Replace [database_name] with the name of your database. Once executed, this statement enables Query Store and starts capturing query performance data.

Configuring Query Store Settings

Query Store has various settings that you can configure to suit your specific requirements. These settings include:

1. Query Store Capture Mode:
   • AUTO: Captures all queries, except those specified as system queries by Azure SQL Database.
   • READ_WRITE: Pauses data capture during high-load periods to reduce overhead.
   • OFF: Disables data capture.

   To configure the capture mode, use the following T-SQL statement:

   ALTER DATABASE [database_name] SET QUERY_STORE (OPERATION_MODE = );

   Replace with the desired capture mode.

2. Query Store Data Flush Interval:

   The data flush interval determines how frequently Query Store writes data to disk. You can configure it using the following T-SQL statement:

   ALTER DATABASE [database_name] SET QUERY_STORE (DATA_FLUSH_INTERVAL_SECONDS = );

   Replace with the desired value in seconds.
3. Query Store Retention:

   Query Store retains data for a specific duration, after which it is automatically purged. You can configure the retention period using the following T-SQL statement:

   ALTER DATABASE [database_name] SET QUERY_STORE (CLEANUP_POLICY = );

   Replace with one of the following options:

   • OFF: Disables data retention.
   • AUTO: Automatically purges data based on the configured size-based or time-based settings.
   • INTERVAL: Purge data based on a specific time interval.
   • STALE_QUERY_THRESHOLD_DAYS: Specify the number of days after which queries are considered stale and are purged.

Monitoring Query Performance

Once Query Store is enabled and configured, you can start monitoring query performance. There are several built-in reports and views available to help you analyze query performance data stored in Query Store.

To view the reports, you can use the following T-SQL statement:

-- Query Store Overview report
SELECT * FROM sys.query_store_runtime_stats;

-- Query Store Query Performance report
SELECT * FROM sys.query_store_query;

You can further customize the reports by adding filters and aggregations based on your specific requirements.

Summary

Configuring Query Store in Azure SQL Database is a crucial step in managing and optimizing query performance. By enabling and configuring Query Store, you gain valuable insights into query execution plans, resource usage, and performance metrics. This allows you to identify and resolve performance issues, leading to improved overall database performance.