Query Store is a new feature in SQL Server that allows users to monitor and troubleshoot performance issues in their databases. It provides a central repository for query plans, execution statistics, and runtime metrics, allowing users to easily identify and fix performance bottlenecks. In this blog post, we will discuss how to use Query Store in a database that is part of an Availability Group, and provide a T-SQL example of the settings required to enable and configure Query Store.
To use Query Store in a database that is part of an Availability Group, the first step is to ensure that Query Store is enabled for the database. This can be done using the following T-SQL command:
ALTER DATABASE [MyDatabase] SET QUERY_STORE = ON;
Next, we need to specify the retention period for Query Store data. This determines how long Query Store data will be retained in the repository and can be set using the following T-SQL command:
ALTER DATABASE [MyDatabase] SET QUERY_STORE (DATA_FLUSH_INTERVAL_SECONDS =
3600);
In this example, the retention period is set to 3600 seconds or one hour. You can adjust this value to suit your specific needs.
Once Query Store is enabled and configured, you can begin using it to monitor and troubleshoot performance issues in your database. For example, you can use the following T-SQL query to view the top 10 longest-running queries in your database:
SELECT TOP 10
query_id,
duration_ms,
execution_count,
last_execution_time
FROM sys.query_store_query
ORDER BY duration_ms DESC;
This query will return a list of the top 10 longest-running queries in your database, along with their query ID, duration in milliseconds, execution count, and last execution time. You can use this information to identify and address performance bottlenecks in your database.
In summary, Query Store is a valuable tool for monitoring and troubleshooting performance issues in a database that is part of an Availability Group. By enabling and configuring Query Store, you can gain insight into the performance of your database and take steps to improve its performance.
