What is SQL Server adaptive query processing (AQP) family and how does it evolve plans?

AQP dynamically adjusts execution strategies using runtime feedback like memory grants, joins, and interleaved execution.

Adaptive Query Processing is a set of SQL Server features that modify execution behavior at runtime or across executions. It includes memory grant feedback, batch mode adaptive joins, and interleaved execution for TVFs. Instead of relying solely on compile-time estimates, SQL Server uses runtime telemetry to adjust resource allocation or change join strategy mid-execution. This reduces performance instability caused by incorrect cardinality estimates.