class ActiveAdmin::Inputs::Filters::SelectInput

def collection

Provides an efficient default lookup query if the attribute is a DB column. 
def collection
  if !options[:collection] && column
    pluck_column
  else
    super
  end
rescue ActiveRecord::QueryCanceled => error
  raise ActiveRecord::QueryCanceled.new "#{error.message.strip} while querying the values for the ActiveAdmin :#{method} filter"
end