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Techniques for query performance troubleshooting and optimization with the Query Store

The Query Store feature in Microsoft SQL Server is a powerful tool that allows database administrators and developers to troubleshoot and optimize query performance. By capturing query execution statistics and execution plans, the Query Store helps identify and address performance issues. In this blog post, we will discuss some techniques for query performance troubleshooting and optimization using the Query Store.

Table of Contents

Enabling the Query Store

To start using the Query Store, you first need to enable it on your SQL Server database. You can do this by executing the following T-SQL command:

ALTER DATABASE [YourDatabaseName] SET QUERY_STORE = ON;

Enabling the Query Store will start capturing query execution data and execution plans for the queries running on that database.

Identifying Queries with Performance Issues

Once the Query Store is enabled, you can use its built-in reports and views to identify queries with performance issues. The Query Store provides information about query duration, CPU usage, and resource consumption, allowing you to pinpoint queries that are slowing down your database.

Analyzing Execution Plans

The Query Store not only captures query execution data but also stores the execution plans associated with each query. Analyzing these execution plans can help you identify performance bottlenecks and inconsistencies.

You can retrieve execution plans from the Query Store by querying the sys.query_store_plan view. By comparing the plans of the same query over different time intervals, you can identify changes in plan choices that may have affected performance.

Forcing Good Execution Plans

In some cases, SQL Server may choose suboptimal execution plans for queries, leading to poor performance. The Query Store allows you to force the use of a specific execution plan for a query, known as plan forcing.

By reviewing the different available plans for a query in the Query Store, you can identify a plan that performs well and force its use using the sp_query_store_force_plan system stored procedure.

EXEC sp_query_store_force_plan @query_id = {query_id}, @plan_id = {plan_id};

Monitoring Query Performance Changes Over Time

The Query Store retains historical data about query performance, allowing you to analyze performance changes over time. By comparing the query statistics and execution plans between different time intervals, you can identify trends and patterns in query performance.

This historical data can be instrumental in troubleshooting recurring performance issues and evaluating the impact of any optimization changes made to your queries or database configuration.

Conclusion

The Query Store is a valuable tool for query performance troubleshooting and optimization in SQL Server. By enabling the Query Store, identifying queries with performance issues, analyzing execution plans, forcing good execution plans, and monitoring performance changes over time, you can improve the overall performance of your SQL Server database.

By leveraging the power of the Query Store, you can diagnose and resolve performance problems more efficiently, minimizing downtime and ensuring optimal query performance. #sqlserver #queryoptimization

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