Siten0308 (12/6/2016)
Hello everyone,so i am wondering, how does cardinality estimator fit in with running the execution plan, is it help give the results of estimate, or part of the actual row count?
Quick answer, the cost based optimizer heavily depends on the cardinality estimations when constructing and optimizing an execution plan. The cardinality estimation therefore will affect many things in the plan such as memory requests, choice of operators etc. This all happens before the query is executed so the cardinality estimator has in that sense nothing to do with the actual execution.
😎