For this reason, SQL Server stores execution plans in a cache (called the plan cache), so that the stored execution plan is reused for subsequent executions of a given query.

In SQL Server 2017, automatic plan correction was added, which allows for the database engine to automatically use the "last known good plan" for a query that has suddenly regressed in performance.

Often, designing databases and speeding up SQL Server queries are treated as a kind of abstract problem: A just "Find this problem, apply this solution" approach to problem solving. In practice, ...