OK, imagine this: you would like to execute some jobs on your server,
but you don't want a fancy job dispatcher. You just want to put some
parameters into a SQL table and have the table updated when the job is
done. Perhaps you have trouble imagining that. However, that was my
fantasy while writing a webapp in codeigniter, a lovely php
framework. I had some statistics to calculate and I didn't want to
calculate them in codeigniter, so I wrote some R scripts. The scripts
are time consuming, so you can't just call them from the server
process. If you do, the webpage will stop loading and wait for the
scripts to finish. Well, just run them in the background and update
the page with javascript when the scripts are finished, right? Not if
there are one hundred people using the server at once. You need to control
the number of simultaneous jobs. Hence the need for a job dispatcher.
