Impact on Mongo query performance due to argument order? - mongodb

Question

General question about Mongo query performance and the order of query arguments.
We have a collection for storing "files" meta data which includes the file-name, and status of the file (integer code value). There will only be a small number of files in the collection with the same name (maybe a few dozen at most), however there can be thousands of files with the same status.
If there is a Mongo query structured something like this:
db.getCollection('files').find( {
'$and': [
{ 'name': 'someFileName.csv' },
{ 'status': { '$in': [ 12, 6 ] } }
]
})
...would it perform any differently then the same query formatted like this:
db.getCollection('files').find( {
'$and': [
{ 'status': { '$in': [ 12, 6 ] } },
{ 'name': 'someFileName.csv' }
]
})
Which is to say: does the order of the $and clause arguments matter? Would scenario #1 perform better than scenario #2 since theoretically the file-name search would eliminate all but a few records? Or does Mongo operate in that manner under the covers?

Answer 1

No, the order of the fields in a query doesn't matter.
Also, due to query fields being implicitly "anded", these would also be equivalent to:
db.getCollection('files').find( {
'status': { '$in': [ 12, 6 ] },
'name': 'someFileName.csv'
})
and
db.getCollection('files').find( {
'name': 'someFileName.csv',
'status': { '$in': [ 12, 6 ] }
})
They're all treated the same by the query analyzer when determining the optimal way to execute the query.