is mongo update ($set) on a single document atomic

Question

I have a code similar to

db.myColletion.update({'_id':ObjectId("...")}, {'$set': {'state': 'CA'}})

Is above an atomic operation?

Do I need to use findAndModify even on single document for atomicity??

Answer 1

Yes, all write operations with MongoDB are atomic at the level of a single document.

The key difference between update and findAnyModify is that the latter also provides you with the original or updated document.