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

Here is a slightly more 'manual' way of doing it:

Essentially, first, get a list of all the unique keys you are interested.

Then perform a search using each of those keys and delete if that search returns bigger than one.

    db.collection.distinct("key").forEach((num)=>{
      var i = 0;
      db.collection.find({key: num}).forEach((doc)=>{
        if (i)   db.collection.remove({key: num}, { justOne: true })
        i++
      })
    });