gistfile1.js

function createFeeds() {
  var limit = 10000;
  var users = db.users.find().limit(limit);
  var skip = 0;

  while(users.length() > 0) {
    for (i = 0; i < users.length(); i++) {
      doc = {home_activities_count: 0, home_activity_ids: [], profile_activities_count: 0, profile_activity_ids: [], user_id: users[i]['_id']};
      db.feeds.insert(doc);
    }
    
    skip = skip + limit;
    users = db.users.find().skip(skip).limit(limit);
  }
}