What is Query Store in SQL Server and where is it located?

Query Store in SQL Server is a feature that automatically collects, stores, and tracks the history of query execution, execution plans, and performance statistics.

Where it is located:

• Query Store is built into each database and stores data within the database itself.
• Query Store data is stored in special internal tables of the database.

Why it is needed:

• Allows analyzing query performance over time.
• Helps identify and fix issues with execution plans (e.g., plan regressions).
• Facilitates query optimization and monitoring without external tools.

To enable Query Store, use the command:

ALTER DATABASE [DatabaseName] SET QUERY_STORE = ON;

After that, SQL Server will start collecting query statistics automatically.