title: How does Node.JS and/or Meteor get a callback from the database when a 3rd party software update the database
body: <p>I would like to use Meteor (Node.JS) to develop an application that will be used by 3,000+ concurrent users on a large size database.
  I have looked at the nice examples and the idea to push changed data to the clients is very nice and very useful, but before I start the development I want to be sure how it works behind the scenes to be sure that when I have the application running with all these users it work fast with standard hardware.
  I also require this to use Oracle as a database, but not sure that it is supported and if not, what are the requirements from an Oracle package to enable this facility.</p>
  
  <p>I think that the server is having an active on going non-blocking query on the OPLOG table in mongodb and that is how we get the callback for all the changes in the database. Is that correct ? if so, is there a similar way to do it in Oracle ?</p>
  
  <p>Thanks Roni.</p>