Mongodb timestamp is very inaccurate - mongoose

Question

I am using mongoose to store objects in mongodb, I record the createdAt date by using Date.now()

What I am finding is that the wrong time is being stored in the database. The difference is very sporadic and has been 7 days, 3 days and even 5 minutes off.

Just this morning I created an object at 8.00AM (GMT+10) AEST, yet the time in the database was 7 days earlier.

This is the database object:

{
  "_id": "554bdfaf797cb8e02753e06f",
  "description": "test d",
  "createdBy": "testuser",
  "key": "f1a593f4dd51e632388a1755e09a7b4dc0bc0e24ef8bcf5cf859ac759a45e8a6",
  "__v": 0,
  "files": [],
  "createdAt": "2015-05-01T05:42:07.687Z"
}

I have seen this issue on both on my mac and win 7.

First noticed on mongodb version 2.6.3, just upgraded to 3.0.2, no change.

Update

I am setting the createdAt date within the schema like so:

var uploadSchema = new Schema({
    createdAt: {
        type: Date,
        required: true,
        default: Date.now()
     },

My database and application are running on the same host.

gist here - https://gist.github.com/reecefenwick/1bcff85d18406b33e5cf

Answer 1

What's going on is that you're calling Date.now() at the time the schema is defined to set the default value for createdAt, and then that value is being used for the default until the next time your app is restarted.

Instead, you want to set the default value to the Date.now function itself so that it will be called each time a new doc is created:

var uploadSchema = new Schema({
    createdAt: {
        type: Date,
        required: true,
        default: Date.now
     },