Using SQL Server Query Store for Advanced Query Performance Analysis

Introduction

SQL Server Query Store is a powerful tool for tracking and analyzing query performance. This guide explores advanced techniques for using Query Store to diagnose query-related issues and optimize database performance with sample code and examples.

1. Enabling Query Store

To use Query Store, you need to enable it on the database level.

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

2. Monitoring Query Performance

Query Store continuously captures query execution data, which can be used to monitor performance.

-- Monitor the performance of top resource-consuming queries
SELECT TOP 10 query_text_id, query_sql_text, avg_duration, execution_count
FROM sys.query_store_runtime_stats
ORDER BY avg_duration DESC;
    

3. Identifying Regressed Queries

Query Store helps you identify queries that have regressed in performance.

-- Find queries with performance regressions
SELECT q.query_id, rs.avg_duration, rs.avg_logical_io_reads
FROM sys.query_store_query q
JOIN sys.query_store_runtime_stats rs ON q.query_id = rs.query_id
WHERE rs.avg_duration > (SELECT AVG(avg_duration) FROM sys.query_store_runtime_stats);
    

4. Query Store Performance Data Capture Policy

You can configure the data retention policy and capture mode for Query Store.

-- Configure Query Store data retention policy
ALTER DATABASE YourDatabase
SET QUERY_STORE (OPERATION_MODE = READ_WRITE, DATA_FLUSH_INTERVAL_SECONDS = 600);
    

5. Forcing Query Execution Plans

You can use Query Store to force a specific execution plan for a query.

-- Force a query execution plan
EXEC sp_query_store_force_plan @query_id = 1, @plan_id = 2;
    

Conclusion

SQL Server Query Store is an invaluable tool for advanced query performance analysis. By enabling Query Store, monitoring query performance, identifying regressions, configuring data retention policies, and forcing execution plans, you can effectively diagnose and optimize query performance to enhance your database's efficiency and reliability.