SQL Server Query Store - Query Performance Analysis for Beginners

SQL Server Query Store is a powerful feature that allows you to capture and analyze query performance data, making it easier to identify and resolve performance issues. In this beginner's guide, we'll explore the fundamentals of Query Store, its significance in query optimization, and provide sample code snippets to help you get started with capturing and analyzing query performance data.

Why Use Query Store?

Query Store offers several benefits for query performance analysis:

• Historical Data: It maintains historical data about query execution plans and performance metrics.
• Plan Forcing: You can force a specific execution plan for problematic queries.
• Troubleshooting: Easily identify and resolve performance regressions and query-related issues.

Enabling Query Store

Let's enable Query Store for a specific database:

-- Enable Query Store for a database
ALTER DATABASE YourDatabase
SET QUERY_STORE = ON;
    

Capturing Query Performance Data

To capture query performance data, use the built-in views and functions provided by Query Store:

-- Retrieve top 10 queries by average duration
SELECT TOP 10
    q.query_id,
    t.query_sql_text,
    rs.avg_duration
FROM sys.query_store_query q
JOIN sys.query_store_query_text t ON q.query_text_id = t.query_text_id
JOIN sys.query_store_runtime_stats rs ON q.query_id = rs.query_id
ORDER BY rs.avg_duration DESC;
    

Using Plan Forcing

If you identify a problematic query, you can force a specific execution plan using Query Store:

-- Force an execution plan for a query
EXEC sp_query_store_force_plan @query_id = 12345, @plan_id = 67890;
    

What's Next?

As you become more proficient with SQL Server Query Store, explore advanced topics like automatic plan correction, analyzing regression scenarios, and using Query Store reports to gain deeper insights into query performance.