Quick Check

1.	Why should you avoid scalar user-defined functions in large result sets?
2.	Why should you avoid query execution time as the primary metric when measuring query performance?
3.	Why should you avoid cursors?

Answers

1.	Avoid scalar user-defined functions because they are not optimized into the query and might therefore significantly degrade query performance.
2.	Query execution time is a poor choice as primary metric because it is affected by many things, such as locks and server load.
3.	Avoid cursors because of their large impact on performance.