title: What are good polling algorithms
body: <p>I am trying to create an application for polling different sensors. I want to make this polling efficient so that I don't poll a slow changing sensor very frequently. On the other hand there may be some sensors like temp sensor whose values keep on changing frequently.</p>
  
  <p>I found an analogy in twitter. When a twitter stream is open how does it automatically give real time notifications of new tweets? . They must be polling a web server of tweet. Right? How this polling rate is decided. There must be some algorithms or may be I am missing proper term/keyword for this thing to Google it. This must have got something to do with push and pull based architectures. Right?</p>