Welcome to SQL Server Query Store, Dev!

If you are a database developer or administrator, you must have heard of SQL Server Query Store. It is a powerful feature of SQL Server that helps you analyze the performance of queries executed on the database. In this article, we will discuss everything you need to know about Query Store, its features, and how you can use it to optimize your database. So, let’s get started!

What is SQL Server Query Store?

SQL Server Query Store is a feature introduced in SQL Server 2016. It is a built-in performance monitoring and troubleshooting tool that helps you identify the queries that are causing performance issues on the database. Query Store captures query execution plans, performance metrics, and runtime statistics, and makes them available for analysis and troubleshooting.

With Query Store, you can monitor query performance over time, identify queries that have regressed, find top resource-consuming queries, and even force the execution plan for specific queries. It is a valuable tool for improving the performance of your database.

Enabling and Configuring Query Store

Query Store is not enabled by default in SQL Server. You need to enable it at the database level. To enable Query Store, you can use either SQL Server Management Studio (SSMS) or Transact-SQL (T-SQL).

Using SSMS, you can enable Query Store by right-clicking on the database, selecting “Properties,” and then navigating to the “Query Store” page. From there, you can enable Query Store and configure its settings.

Using T-SQL, you can enable Query Store by executing the following command:

T-SQL Command	Description
ALTER DATABASE [DatabaseName]	Specifies the database you want to enable Query Store for.
SET QUERY_STORE = ON;	Enables Query Store for the database.

You can configure Query Store settings such as data retention, capture mode, and size limit. The default settings are usually sufficient for most databases, but you can adjust them according to your needs.

Using Query Store for Query Performance Analysis

Once Query Store is enabled and configured, it starts capturing query performance data automatically. You can use the Query Store reports in SSMS to analyze query performance data.

The Query Store reports provide valuable insights into the performance of queries executed on the database. You can use these reports to find queries that have regressed, identify top resource-consuming queries, and analyze query execution plans.

The Query Store reports include the following:

• Top Resource-Consuming Queries
• Queries with Forced Plans
• Regressed Queries
• Tracked Queries
• Overall Query Performance

Top Resource-Consuming Queries

The Top Resource-Consuming Queries report shows the top queries that consume CPU, memory, and I/O resources. You can use this report to find queries that are causing performance issues and optimize them.

Queries with Forced Plans

The Queries with Forced Plans report shows the queries for which you have manually forced an execution plan. You can use this report to monitor the execution plans of specific queries and ensure they are not changed by the Query Optimizer.

Regressed Queries

The Regressed Queries report shows the queries that have regressed in performance. You can use this report to identify queries that were previously performing well but are now causing performance issues.

Tracked Queries

The Tracked Queries report shows all the queries that have been executed on the database. You can use this report to monitor query performance over time and identify trends.

Overall Query Performance

The Overall Query Performance report shows the performance of all queries executed on the database. You can use this report to identify the overall performance trends of the database and plan for future optimizations.

Using Query Store to Force Plan Execution

SQL Server Query Optimizer is a complex engine that determines the optimal execution plan for each query. However, in some cases, the Query Optimizer may choose a suboptimal execution plan that causes performance issues.

With Query Store, you can force the execution plan for specific queries to ensure that they are executed using a specific plan. You can use the “Plan Forcing” feature in Query Store to force the execution plan for specific queries.

To force an execution plan, you can use either SSMS or T-SQL. Using SSMS, you can right-click on a query in the Query Store report and select “Force Plan.” From there, you can select the execution plan you want to force.

Using T-SQL, you can force an execution plan by executing the following command:

T-SQL Command	Description
USE [DatabaseName];	Specifies the database you want to force the plan for.
EXEC sp_query_store_force_plan [@query_id], [@plan_id];	Forces the execution plan for the specified query and plan IDs.

FAQ

Q1. How does Query Store impact database performance?

Enabling Query Store does have a small impact on database performance, as it captures query performance data. However, the impact is minimal and should not affect the overall performance of the database.

Q2. Can I disable Query Store after enabling it?

Yes, you can disable Query Store by setting the “QUERY_STORE” option to “OFF” using T-SQL.

Q3. How long does Query Store retain data?

Query Store retains data for a configurable period, which defaults to 30 days. You can configure the retention period using SSMS or T-SQL.

Q4. Can I use Query Store in SQL Server Management Studio?

Yes, you can use Query Store in SQL Server Management Studio to analyze query performance data, force execution plans, and configure Query Store settings.

Q5. Can I use Query Store in Azure SQL Database?

Yes, Query Store is also available in Azure SQL Database. However, some features may be limited or not available in Azure SQL Database compared to SQL Server.

Conclusion

SQL Server Query Store is a powerful feature that helps you analyze the performance of queries executed on the database. With Query Store, you can monitor query performance over time, identify queries that have regressed, find top resource-consuming queries, and even force the execution plan for specific queries. It is a valuable tool for improving the performance of your database. We hope this article has provided you with a comprehensive understanding of Query Store and its features. If you have any questions, please feel free to ask!