Node.js: "process run out of memory"

I have the following code which leads to the error: FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

It doesn't make any difference whether I set --max_old_space_size=4096 (or bigger numbers) or not. I have 16 GB RAM on my PC.

System: win10/node.js 6.9.2/mongodb 3.4

I have over 16 000 000 messages in the "chatModel". With a smaller amount of messages the code works.

Do you have any suggestions how to solve the problem/optimize the code?

function sortOutMessages(){

var atSymbol = "@";
var rgx = new RegExp("^\\" +atSymbol);


chatModel.find({messageContent: rgx}, function (err, doc){

    var docs = doc;
    var docsLength = docs.length;

    for (var i =0; i<docsLength;i++) {
        var directedMessagesObj = new directedMessagesModel
        ({
            timeStamp: docs[i].timeStamp,
            channelName: docs[i].channelName,
            userName: docs[i].userName,
            userID: docs[i].userID,
            messageContent: docs[i].messageContent,
            messageLength: docs[i].messageLength,
            subscriber: docs[i].subscriber,
            turbo: docs[i].turbo,
            moderator: docs[i].moderator
        });

        directedMessagesObj.save({upsert:true}, function (err) {
            var fs = require('fs');
            if (err) {
                    fs.appendFile("undefinedLog.txt", "error at " + new Date().toLocaleString() + " directedMessagesObj.save " + "\r\n")
                    loggerWinston.warn("error at " + new Date().toLocaleString() + " directedMessagesObj.save " + "\r\n");
                    return console.log(err);
            }

        });
    }

});



}

via dmtrshpv