Explain() error for findOne query

[wedothebest_We_do_the_Best (WeDoTheBest4You)]

Hello,

It is a coding shortcut only.
findOne() is basically a shorthand to do a find().limit(1)

The query optimisation and execution are the same.

As you know while find returns a cursor, findOne returns a document instead. The method explain() belongs to cursor object. This is the reason it is not possible call explain with findOne.

Please read this discussion:

Performance of find & project vs findOne and then grabbing the property on the result

I need just one property of one document. I see that I can’t .project after .findOne, only after .find. I’m concerned about the data egress (although it is small) and the performance of the request. With my understanding of how MongoDB queries a collection - once it finds a satisfying record in findOne it immediately returns. But using find, it needs to search through the whole collection - right? If it matters, I am searching on _id (a single _id), so since I’m searching on an index, how w…

Thanks
WeDoTheBest4You