One slow query

gistfile1.txt

# This query takes only a fraction of a second locally and looong on heroku
# Heroku app name: floating-moon-774
# MongoHQ 'eko', app: 'app558262'
Marker.where(:finished => true, :operator_comment => false).desc(:created_at).limit(4)

# via 'heroku console':
>> puts Time.now ; 100.times { Marker.where(:finished => true, :operator_comment => false).desc(:created_at).limit(4).entries} ; puts Time.now
Thu Jun 30 07:22:40 -0700 2011
Thu Jun 30 07:23:29 -0700 2011