Query Store enables you to identify queries that used to perform well but are now performing poorly. By collecting and presenting detailed historic information about all queries, Query Store significantly reduces the time to diagnose and resolve performance issues. If a query generates a different plan, you can use Query Store to analyze the query plan changes, possible performance degradation, or force the system to use a particular plan for your query.
For more information about how to get started with Query Store, review
Query Store: A flight data recorder for your database blog or the
Query Store documentation.