What would be the fastest way select 1 million users from a collection in MongoDB?
<pre><code>db.users.find({role:'seeker'}, {
    "email": 1,
    "name": 2
})
</code></pre>

<p>As suggested I ran</p>

<pre><code>db.users.find({role:'seeker'}).explain()
</code></pre>

<p>to get this</p>

<pre><code>{
    "queryPlanner" : {
        "plannerVersion" : 1,
        "namespace" : "users",
        "indexFilterSet" : false,
        "parsedQuery" : {
            "role" : {
                "$eq" : "seeker"
            }
        },
        "winningPlan" : {
            "stage" : "COLLSCAN",
            "filter" : {
                "role" : {
                    "$eq" : "seeker"
                }
            },
            "direction" : "forward"
        },
        "rejectedPlans" : [ ]
    },
    "serverInfo" : {

    },
    "ok" : 1
}
</code></pre>

<p>If I use the query above it takes  15-20 seconds to respond. I need to send email campaigns to bulk users every day. I have a node.js task to do this and while this task runs in background it slows down everything else even though node.js is not supposed to be blocking</p>