On my course model, newly specified:

index(

{ stub: 1, openlibrary: 1, title: 1, description: 1 }

)

ran

rake db:mongoid:create_indexes

twice. Now...

2.2.0 :001 > Course.where(stub:"bio_oa_ll_100").first
=> nil
2.2.0 :003 > Course.where(stub:"bio_oa_ll_100")
=> #<Mongoid::Criteria
selector:

{"stub"=>"bio_oa_ll_100"}
options: {}
class: Course
embedded: false>

2.2.0 :004 > Course.where(stub:"bio_oa_ll_100").count
=> 1
2.2 .0 :005 > Course.where(stub:"bio_oa_ll_100").first
=> nil
2.2.0 :006 > Course.where(stub:"bio_oa_ll_100").all
=> #<Mongoid::Criteria
selector: {"stub"=>"bio_oa_ll_100"}

options: {}
class: Course
embedded: false>

2.2.0 :007 > Course.where(stub:"bio_oa_ll_100").entries
=> [#<Course _id: 53876d686f70650c4d000000 [........]

What on earth?

Fixed with this:

rake db:mongoid:remove_indexes

Maybe amend the behavior of the first rake command (create_indexes) - should this even be possible? Wrecked my site for a few minutes.