Query Store Enhancements

 Query Store in SQL Server has received several enhancements in recent versions, making it even more powerful for performance monitoring and query tuning. Here are some of the key enhancements:

1. Query Store for Read-Only Replicas (SQL Server 2019)

• Query Store now supports capturing performance data on read-only replicas in Always On Availability Groups. This allows you to monitor and tune queries running on these replicas without impacting the primary.

2. Custom Capture Policies (SQL Server 2019)

• You can define custom capture policies for Query Store, which allows you to control which queries are captured based on factors such as execution frequency, resource consumption, or duration. This helps reduce overhead by ignoring less important queries.

3. Automatic Plan Correction (SQL Server 2017+)

• SQL Server can automatically detect and correct query performance regressions by reverting to an older query plan that is known to perform better. This is part of the Intelligent Query Processing (IQP) feature set.

4. Improved User Interface in SSMS

• The Query Store UI in SQL Server Management Studio (SSMS) has improved significantly, offering better visualization for comparing query performance over time, analyzing plan changes, and more.

5. Hybrid Workloads and Query Store for Cloud Environments

• Azure SQL Database and SQL Managed Instance also benefit from Query Store enhancements, such as the ability to monitor query performance across different environments (on-premises and cloud) and integrate with Azure monitoring tools.

6. Wait Statistics

• Query Store now includes wait statistics, which help you understand the causes of performance bottlenecks related to waits (e.g., I/O, locks, CPU). This provides better insight into the actual root causes of performance issues.

7. Aggregated Query Data

• Query Store now offers enhanced options for aggregating query data, making it easier to analyze query patterns and performance over longer periods of time without needing to focus on individual executions.

8. Query Store on a Per-Database Basis

• You can now enable or disable Query Store at the database level, providing more control over where Query Store is used and reducing unnecessary overhead in less critical databases.

These enhancements help developers and DBAs monitor, troubleshoot, and optimize query performance more efficiently across various environments.