I am not able to understand this portion of the Lesson 9 ( Module 2 ) in Filemaker Training Series Advanced Book : -
"Note that there are some circumstances where it is useful to place filters on the relationship rather than the portal. For instance, the Go To Related Records script step finds a set of related records, and Aggregate functions like Count and Sum operate on a set of related records. If that set of related records is much larger than what you actually need, you can speed performance by limiting the relationship with a filter so the aggregation takes less time."
Can anyone explain how this works .... and maybe give some examples ?