Mongo Query to Delete Celery succesfull entries on a large collection, slowly but surely.

delete_celery.js

var COUNTER = 900;

function deleteSome(count) {
    var itemsToDel = db.tasks.find({status: "SUCCESS"}, {_id: 1}).sort({created_at: 1}).limit(count).toArray();
    var IDs = itemsToDel.map(function(item){ return item["_id"]})
    if (IDs.length > 0 ) {
        db.tasks.remove({"_id": {"$in": IDs } });
        sleep(5000);
    } else {
        COUNTER++;
        print("delete skipped - " + COUNTER);
    }
}

//LOG BEFORE
var beforeCount = db.tasks.count();
print(beforeCount)
//USAGE
for (; COUNTER > 0; COUNTER--) { deleteSome(2000)}
//COUNTER
var afterCount = db.tasks.count();
print("Reduced" + (beforeCount - afterCount) + ", And still to go - " + afterCount);