Sorting of infinity and -infinity does not produce expected results:

> db.test.save(

{number: 1}

)
> db.test.save(

{number: 2}

)
> db.test.save(

{number: 3}

)
> db.test.save(

{number: Infinity}

)
> db.test.save(

{number: -Infinity}

)
> db.test.find().sort(

{"number": 1}

)

{ "_id" : ObjectId("4bbdd056ac64d9763fe0bccf"), "number" : Infinity } { "_id" : ObjectId("4bbdd059ac64d9763fe0bcd0"), "number" : -Infinity } { "_id" : ObjectId("4bbdd04dac64d9763fe0bccc"), "number" : 1 } { "_id" : ObjectId("4bbdd04fac64d9763fe0bccd"), "number" : 2 } { "_id" : ObjectId("4bbdd051ac64d9763fe0bcce"), "number" : 3 }

The expected order is [-Infinity, 1, 2, 3, Infinity].