javacript insert into MongoDB, how to change write concern

Question

javacript insert into MongoDB, how to change write concern

I want to test the insert rate with write concern = 0. But dont know where to change in js code.

db.testData.insert( 
        {"global_node_id": 1,
        "some_node_id": 1,
        "data": "data"})

Here is one line in js to insert. I didnt understand that where to put the {w:0}

Is it some where when I do connect to the database? or in the insert command?

I tried with following:

conn = new Mongo()
db = conn.getDB("myDatabase",{w:0});

No error pop up, but it does not speed up. So I guess this is not the way.

node.js
mongodb

Answer 1

Assuming by "js code" you mean "in the mongo shell", as that is what your code implies, you specify unacknowledged write concern in insert operations like so:

> db.test.insert({a: 1}, {writeConcern: {w: 0}})
WriteResult({ })

Answer 2

Short version

db.testData.insert( { 'global_node_id': 1, 'some_node_id': 1, 'data': 'data' }, { writeConcern: {w:0} } )

Long version

I'm assuming (giving your code and the node.js tag) that you are actually using the NodeJS driver for MongoDB, not the mongo shell.

The syntax for insert is:

collection.insert(docs[[, options], callback])

(as can be seen in the docs).

So, you have an optional second argument that stands for the options. You can pass the write concern in the options as shown there.