MyColl has 20 documents, as count() and find().count() confirm, but adding limit(10) still returns 20:

  db.MyColl.count()
    20

  db.MyColl.find().count()
    20

  db.MyColl.find().limit(10).count()
    20

This is the correct syntax as per our documentation for cursor.count() - the default behaviour when applySkipLimit is not set to true is to ignore any skip(n) and limit(m) methods.

However, it is counter-intuitive for a user to have included the limit(10) but to also want it to be ignored. Note further that itcount() behaves differently:

  db.MyColl.find().limit(10).itcount()
    10

Conclusion: the default value for applySkipLimit should be true.