How does Query Store help with performance regression?

Query Store maintains historical query text, plans, and runtime statistics. When a query suddenly becomes slower, Query Store can help determine whether its execution plan changed and compare the performance of different plans over time.

Depending on SQL Server capabilities and operational policy, a known-good plan can sometimes be forced while the underlying cause is investigated. Query Store hints can also apply certain query hints without changing application SQL in supported versions.

Plan forcing should be monitored because data distributions and workloads can change; it is not a permanent substitute for understanding the regression.