How to remove duplicates based on a key in Mongodb?

Question

I have a collection in MongoDB where there are around (~3 million records). My sample record would look like,

 { \"_id\" = ObjectId(\"50731xxxxxxxxxxxxxxxxxx         


        

Answer 1

This is the easiest query I used on my MongoDB 3.2

db.myCollection.find({}, {myCustomKey:1}).sort({_id:1}).forEach(function(doc){
    db.myCollection.remove({_id:{$gt:doc._id}, myCustomKey:doc.myCustomKey});
})

Index your customKey before running this to increase speed