Get biggest document in mongo

doc_size.js

#mongodb queries

db.objects.find({ $and: [
    { _id: { $gt: ObjectId("5b06052649f0a0999558b960")} },
    { _key: { $not: /^anal.*/ } },
    { _key: { $not: /^group.*/ } },
    { _key: { $not: /^user/ } },
    { _key: { $not: /^post/ } },
    { _key: { $not: /^topic/ } },
    { _key: { $not: /^chat/ } },
    { _key: { $not: /^follow/ } },
    { _key: { $not: /^category/ } },
    { _key: { $not: /^categories/ } },
    { _key: { $not: /^message/ } },
    { _key: { $not: /^uid/ } },
    { _key: { $not: /^tid/ } },
    { _key: { $not: /^cid/ } },
    { _key: { $not: /^pid/ } },
    { _key: { $not: /^ip/ } },
    { _key: { $not: /^flag/ } },
    { _key: { $not: /^fullname/ } },
    { _key: { $not: /^appId:uid/ } },
    { _key: { $not: /^diff/ } },
    { _key: { $not: /^banned/ } },
    { _key: { $not: /^upload/ } },
    { _key: { $not: /^event/ } },
] }).sort({_id: 1});


// biggest object
var max = 0;
var key = '';
db.objects.find().forEach(function(obj) {
    var curr = Object.bsonsize(obj);
    if(max < curr) {
        max = curr;
        key = obj._key;
    }
})
print(key);
print(max);

//execute with:
//mongo localhost:27017/<db_name> doc_size.js


// group by keys
db.objects.aggregate([
    { $group: { _id: { _key: '$_key'}, count: { $sum: 1 } } } ,
    { $sort: { count: -1 } },
    { $limit: 100 },
], { "allowDiskUse" : true });