query store in sql server

Title: Understanding Query Store in SQL ServerDear Dev,SQL Server is a relational database management system that stores data in the form of tables. Query Store in SQL Server is a feature that helps in analyzing query performance and execution history. It is also known as a flight data recorder for SQL Server queries, as it records all the queries executed in SQL Server.In this article, we will discuss Query Store in SQL Server, its importance, and how it can be used to improve query performance. We will also answer some frequently asked questions related to Query Store.1. What is Query Store in SQL Server?Query Store is a built-in feature in SQL Server 2016 and above. It is used for capturing query execution history, execution plans, and other related statistics. Query Store stores this data in a system database called ‘QueryStore.’2. What is the importance of Query Store in SQL Server?Query Store is essential for understanding query performance in SQL Server. It helps in identifying and troubleshooting query performance issues. With Query Store, one can compare the performance of different query versions and identify the most efficient query.3. How can Query Store be enabled in SQL Server?Query Store can be enabled at the database level using the following command:“`ALTER DATABASE AdventureWorks2019 SET QUERY_STORE = ON;“`4. What are the different Query Store views in SQL Server?SQL Server provides various Query Store views to analyze query performance. Some of the important Query Store views are:- sys.query_store_query- sys.query_store_plan- sys.query_store_runtime_stats- sys.query_store_wait_stats5. How can Query Store be used to improve performance?Query Store can be used to identify and troubleshoot performance issues in the following ways:- Compare query performance over time.- Identify queries with high resource consumption.- Analyze execution plans to find inefficient queries.- Force a specific query plan for a particular query.

Understanding Query Store Components

Query Store consists of various components that help in capturing and analyzing query performance data. Let’s discuss these components in detail:

1. Query Store Capture Policy

Query Store Capture Policy is used to define the data that needs to be captured in Query Store. It includes query text, execution plans, and other related statistics.Example:“`ALTER DATABASE AdventureWorks2019 SET QUERY_STORE_CAPTURE_MODE = ALL;“`This command enables Query Store to capture all the data related to query execution.

2. Query Store Flush Policy

Query Store Flush Policy is used to define when the data needs to be flushed from Query Store. It includes maximum storage size, retention period, and frequency of flush.Example:“`ALTER DATABASE AdventureWorks2019 SET QUERY_STORE_FLUSH_INTERVAL = 900; — in seconds“`This command enables Query Store to flush data every 900 seconds.

3. Query Store Query Store Options

Query Store Options are used to define the behavior of Query Store. It includes options like data purging, ad-hoc query capture, and query plan forcing.Example:“`ALTER DATABASE AdventureWorks2019 SET QUERY_STORE_OPTIONS (QUERY_CAPTURE_MODE = All, MAX_PLANS_PER_QUERY = 1);“`This command enables Query Store to capture all the queries and store only one execution plan per query.

Query Store Reports

Query Store provides various reports to help in analyzing query performance. Let’s discuss some of the important reports:

1. Top Resource Consuming Queries

This report helps in identifying queries that consume high resources like CPU, memory, and I/O.

2. Tracked Queries Report

This report shows the execution history and performance of all tracked queries.

3. Query Performance Insight

This report provides insights into query performance by showing query execution times, resource consumption, and execution plans.

Query Store FAQ

1. What is the size limit of Query Store?

The size limit of Query Store is determined by the maximum database size limit. By default, Query Store is limited to 100 MB of space.

2. How can Query Store be disabled?

Query Store can be disabled using the following command:“`ALTER DATABASE AdventureWorks2019 SET QUERY_STORE = OFF;“`

3. Can Query Store be used with Azure SQL Database?

Yes, Query Store is supported in Azure SQL Database.

Conclusion

Query Store is an essential tool for analyzing query performance in SQL Server. It helps in identifying and troubleshooting query performance issues. Query Store provides various reports and views to help in analyzing query performance. By using Query Store, one can improve query performance and optimize database performance.We hope this article helped you in understanding Query Store in SQL Server.