tips.md

#tips

check doc exists using find().limit(1)

https://blog.serverdensity.com/checking-if-a-document-exists-mongodb-slow-findone-vs-find/

However, it is significantly faster to use find() + limit() because findOne() will always read + return the document if it exists. find() just returns a cursor (or not) and only reads the data if you iterate through the cursor.

So instead of:

db.collection.findOne({_id: "myId"}, {_id: 1})

you should use:

db.collection.find({_id: "myId"}, {_id: 1}).limit(1)