//db.adminCommand( { setFeatureCompatibilityVersion: "4.2" } );
use wildcard
db.noIndex.drop();
db.singleIndex.drop();
db.manyIndexes.drop();
db.wildcardIndex.drop();

var i = 0;
var docs = [];

for (i = 1; i < 100000; i++) {
  var data = {
    _id: i,
    data: {
      a: Math.round(Math.random() * 10000),
      b: Math.round(Math.random() * 10000),
      c: Math.round(Math.random() * 10000),
      d: Math.round(Math.random() * 10000),
      e: Math.round(Math.random() * 10000),
      f: Math.round(Math.random() * 10000),
      g: Math.round(Math.random() * 10000)
    }
  };
  docs.push(data);
}

db.singleIndex.createIndex({"data.a":1});

db.manyIndexes.createIndex({"data.a":1});
db.manyIndexes.createIndex({"data.b":1});
db.manyIndexes.createIndex({"data.c":1});
db.manyIndexes.createIndex({"data.d":1});
db.manyIndexes.createIndex({"data.e":1});
db.manyIndexes.createIndex({"data.f":1});
db.manyIndexes.createIndex({"data.g":1});

db.wildcardIndex.createIndex({"data.$**":1});

function updateIt(collectionName) {
  var start=new Date();
  var rc=db.getCollection(collectionName).update({},
                                                 {$inc:{"data.a":1,"data.b":1,"data.c":1,"data.d":1,"data.e":1,"data.f":1,"data.g":1}},
                                                 {multi:true});
  //printjson(rc);
  var elapsed=((new Date())-start);
  print('update,',collectionName,',',elapsed,'ms');
}

function insertIt(collectionName,data) {
  var start=new Date();
  var rc=db.getCollection(collectionName).insertMany(data);
  //printjson(rc);
  var elapsed=((new Date())-start);
  print('insert,',collectionName,',',elapsed,',ms');
}

function deleteIt(collectionName) {
  var start=new Date();
  var rc=db.getCollection(collectionName).deleteMany({});
  //printjson(rc);
  var elapsed=((new Date())-start);
  print('delete,',collectionName,',',elapsed,',ms');
}

function findIt(collectionName) {
  var start=new Date();
  var data=db.getCollection(collectionName).find({"data.a":{$lt:100}}).toArray();
  //printjson(rc);
  var count=data.length;
  var elapsed=((new Date())-start);
  print('find,',collectionName,',',elapsed,',ms,',count);
}

insertIt('noIndex',docs);
insertIt('singleIndex',docs);
insertIt('manyIndexes',docs);
insertIt('wildcardIndex',docs);

findIt('noIndex');
findIt('singleIndex');
findIt('manyIndexes');
findIt('wildcardIndex');

updateIt('noIndex');
updateIt('singleIndex');
updateIt('manyIndexes');
updateIt('wildcardIndex');

deleteIt('noIndex');
deleteIt('singleIndex');
deleteIt('manyIndexes');
deleteIt('wildcardIndex');