HTML and CSS Reference
Figure D.3. The optimum case for polling: new data is available regularly, and the frequency of the new data being
available is similar to the number of polls.
Even with the optimum polling solution you'll still have polls when there's no data, and for
other polls data will be available for nearly the full length of time between polls. And the
optimum polling solution is hard to achieve. The average chat room will have busy periods
and quiet periods, and when those occur depends on the confluence of schedules of people
living thousands of miles apart. It's more likely the application will spend more time in the
degenerate cases (see figure D.4 ).