rails/rails — pull request #3870 by seanwalbran (2011-12-05 22:52:38+00:00)
Title: bypass preloading for ids_reader

- When fetching ids for a collection, bypass preloading to avoid the unnecessary performance overhead.
- As a side effect, also allow for bypassing preloading in other cases where the preloading may also not be desired (e.g., some_big_association.select(:email_address) ) by invoking to_array with with_preload=false.

Loosely related to #2020 and #3868.